Efficiency Investigation of a Helical Turbine for Harvesting Wind Energy
A Thesis presented by
Nathan Willard
To
The Department of Mechanical and Industrial Engineering
In partial fulfillment of the requirements
For the degree of
Master of Science
In
Mechanical Engineering
In the field of
Thermofluids Engineering
Northeastern University
Boston, Massachusetts
September 2011
ii
Abstract
In recent times, there has been an increased interest in wind energy due to concerns about the pollution
caused by burning fossil fuels and their rising prices. Most wind turbines in use today are conventional
wind mills with three airfoil shaped blades arraigned around a horizontal axis. These turbines must be
turned to face into the wind and in general require significant air velocities to operate. Another style of
turbine is one where the blades are positioned vertically or transverse to the axis of rotation. These
turbines will always rotate in the same direction regardless of the fluid flow. Due to the independence
from the direction of the fluid flow, these turbines have found applications in tidal and surface current
flows. To see how effective this sort of turbine would be in air, a helical turbine based on the designs and
patents of Dr. Alexander M. Gorlov was chosen. His turbine was developed to improve upon the design
of Georges J. M. Darrius by increasing the efficiency and removing pulsating stresses on the blades,
caused by the blades hitting their aerodynamic stall in the course of rotation, which often resulted in
fatigue failure in the blades or the joints that secured them to the shaft. The turbine takes the Darrius type
turbine, which has a plurality of blades arranged transverse to the axis of rotation, and adds a helical twist
to their path, insuring that regardless of the position of the turbine, a portion of the blade is always
positioned in the position that gives maximum lift. This feature reduces the pulsations that are common
in a Darrius type turbine. In his investigations, Gorlov claims that his turbine is significantly more
efficient than Darrius’ and has achieved overall efficiencies between 30% and 35%. For this
investigation, a helical turbine was tested inside and outside a wind tunnel using an electric generator
(inside tests only) and a torque meter paired with a tachometer to measure the output power of the turbine
and calculate its efficiency. In the end, the turbine did not come close to the claimed 30% efficiency,
reaching at best an efficiency of around 0.35%. Further investigations should be made to determine why
the results from this investigation were as low as they are.
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Acknowledgements
First, I would like to express my deep appreciation for my advisor; Prof. M. E. Taslim for
guiding me through the process of conducting this investigation.
I would also like to give special thanks to Jonathan Doughty and Kevin McCue for the aid that
they have given me in the construction and testing of the turbine.
Thirdly, I would like to give thanks to my colleagues, Mehdi Abedi, Nathaniel Rosso and
Adebayo Adebiyi for the hints and tips they have given me through conversation regarding this
investigation.
Finally, I would like to express my gratitude to my family for supporting me in this endeavor.
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Table of Contents Abstract ......................................................................................................................................................... ii
Acknowledgements ...................................................................................................................................... iii
List of Figures .............................................................................................................................................. vi
List of Tables ............................................................................................................................................... ix
Nomenclature ............................................................................................................................................... xi
Chapter 1 ....................................................................................................................................................... 1
1.1 Introduction ......................................................................................................................................... 1
1.2 Literature Review ................................................................................................................................ 2
Chapter 2 ....................................................................................................................................................... 6
2.1 Overview of Experiment ..................................................................................................................... 6
2.2 Design and Construction of the Turbine ............................................................................................. 7
2.2.1 Overview of Design ..................................................................................................................... 7
2.2.2 Shaft Design ................................................................................................................................. 8
2.2.3 Flange Design .............................................................................................................................. 8
2.2.4 Spoke Arm Design ....................................................................................................................... 9
2.2.5 Blade Design .............................................................................................................................. 10
2.3 Selection of Instrumentation ............................................................................................................. 12
2.3.1 Torque Meter ............................................................................................................................. 12
2.3.2 Tachometer ................................................................................................................................ 14
2.3.3 Generator .................................................................................................................................... 14
2.3.4 Pitot Tube and Manometer ......................................................................................................... 15
2.3.5 Wind Meter ................................................................................................................................ 15
2.4 Test Setup and Procedure .................................................................................................................. 16
2.4.1 Layout of the Test Chamber ....................................................................................................... 16
2.4.2 Wind Tunnel Tests ..................................................................................................................... 17
2.4.3 Out of Wind Tunnel Tests .......................................................................................................... 19
2.4.4 Calibration Check on Handheld Wind Meter ............................................................................. 20
Chapter 3 ..................................................................................................................................................... 23
3.1 Wind Tunnel Tests with Generator ................................................................................................... 23
3.1.1 Results from 0.55in Oil Test ...................................................................................................... 24
3.1.2 Results from 0.60in Oil Test ...................................................................................................... 26
3.1.3 Results from 0.65in Oil Test ...................................................................................................... 28
3.1.4 Results from 0.70in Oil Test ...................................................................................................... 30
3.1.5 Results from 0.75in Oil Test ...................................................................................................... 32
3.1.6 Results from 0.80in Oil Test ...................................................................................................... 34
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3.1.7 Results from 0.85in Oil Test ...................................................................................................... 36
3.1.8 Results from 0.90in Oil Test ...................................................................................................... 38
3.1.9 Results from 0.95in Oil Test ...................................................................................................... 40
3.1.10 Results from 1.0in Oil Test ...................................................................................................... 42
3.1.11 Rotational Velocity Results ..................................................................................................... 44
3.1.12 Turbine Power Results ............................................................................................................. 46
3.1.13 Turbine Efficiency Results ....................................................................................................... 48
3.2 Wind Tunnel Tests with Torque Meter ............................................................................................. 49
3.3 Out of Wind Tunnel Test with Torque Meter ................................................................................... 51
3.3.1 Fan 12in from Turbine ............................................................................................................... 52
3.3.2 Fan 24in from Turbine. .............................................................................................................. 55
3.4 Conclusions ....................................................................................................................................... 58
3.5 Further Investigations ....................................................................................................................... 59
Works Cited ................................................................................................................................................ 61
Appendix A: Technical Drawings of Turbine ............................................................................................. 62
Appendix B: Raw Data ............................................................................................................................... 67
Appendix C: Calibration Information ......................................................................................................... 88
vi
List of Figures
Figure 1-1: Figure 3 from Darrius' Patent for his Turbine. (1) ..................................................................... 2
Figure 2-1: Exploded View of Turbine Assembly ........................................................................................ 7
Figure 2-2: Flange Design ............................................................................................................................ 9
Figure 2-3: Spoke Arm Design ..................................................................................................................... 9
Figure 2-4: NACA0018 Airfoil Profile ....................................................................................................... 10
Figure 2-5: Top View of Turbine Blade ..................................................................................................... 11
Figure 2-6: Side View of Turbine Blade ..................................................................................................... 11
Figure 2-7: Blade Half ................................................................................................................................ 12
Figure 2-8: Himmelstein Torque Meter ...................................................................................................... 13
Figure 2-9: LED Tachometer ...................................................................................................................... 14
Figure 2-10: Generator ................................................................................................................................ 15
Figure 2-11: Kestrel Wind Meter ................................................................................................................ 16
Figure 2-12: Test Chamber Layout, Top Down View and Side View ........................................................ 17
Figure 2-13: Torque Meter Configuration .................................................................................................. 18
Figure 2-14: Generator Set Up .................................................................................................................... 18
Figure 2-15: Out of Wind Tunnel Set Up ................................................................................................... 20
Figure 3-1: Rotational Velocity at 0.55in Oil ............................................................................................. 24
Figure 3-2: Output Power at 0.55in Oil ...................................................................................................... 25
Figure 3-3: Efficiency at 0.55in Oil ............................................................................................................ 25
Figure 3-4: Rotational Velocity at 0.6in Oil ............................................................................................... 26
Figure 3-5: Output Power at 0.6in Oil ........................................................................................................ 27
Figure 3-6: Efficiency at 0.6in Oil .............................................................................................................. 27
Figure 3-7: Rotational Velocity at 0.65in Oil ............................................................................................. 28
Figure 3-8: Output Power at 0.65in Oil ...................................................................................................... 29
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Figure 3-9: Efficiency at 0.65in Oil ............................................................................................................ 29
Figure 3-10: Rotational Velocity at 0.7in Oil ............................................................................................. 30
Figure 3-11: Output Power at 0.7in Oil ...................................................................................................... 31
Figure 3-12: Efficiency at 0.7in Oil ............................................................................................................ 31
Figure 3-13: Rotational Velocity at 0.75in Oil ........................................................................................... 32
Figure 3-14: Output Power at 0.75in Oil .................................................................................................... 33
Figure 3-15: Efficiency at 0.75in Oil .......................................................................................................... 33
Figure 3-16: Rotational Velocity at 0.8in Oil ............................................................................................. 34
Figure 3-17: Output Power at 0.8in Oil ...................................................................................................... 35
Figure 3-18: Efficiency at 0.8in Oil ............................................................................................................ 35
Figure 3-19: Rotational Velocity at 0.85in Oil ........................................................................................... 36
Figure 3-20: Output Power at 0.85in Oil .................................................................................................... 37
Figure 3-21: Efficiency at 0.85in Oil .......................................................................................................... 37
Figure 3-22: Rotational Velocity at 0.9in Oil ............................................................................................. 38
Figure 3-23: Output Power at 0.9in Oil ...................................................................................................... 39
Figure 3-24: Efficiency at 0.9in Oil ............................................................................................................ 39
Figure 3-25: Rotational Velocity at 0.95in Oil ........................................................................................... 40
Figure 3-26: Output Power at 0.95in Oil .................................................................................................... 41
Figure 3-27: Efficiency at 0.95in Oil .......................................................................................................... 41
Figure 3-28: Rotational Velocity at 1in Oil ................................................................................................ 42
Figure 3-29: Output Power at 1in Oil ......................................................................................................... 43
Figure 3-30: Efficiency at 1in Oil ............................................................................................................... 43
Figure 3-31: Rotational Velocity of the Turbine Across all Wind Velocities. ........................................... 44
Figure 3-32: Percent Error .......................................................................................................................... 45
Figure 3-33: Output Power from Generator and Air Power ....................................................................... 46
Figure 3-34: Output Power Error ................................................................................................................ 47
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Figure 3-35: Efficiency ............................................................................................................................... 48
Figure 3-36: Output Power of Turbine using the Torque Meter and Generator ......................................... 50
Figure 3-37: Rotational Velocity, Torque Meter vs. Generator .................................................................. 51
Figure 3-38: Torque from Tests Taken with Fan 12in from Turbine.......................................................... 52
Figure 3-39: Rotational Velocity Taken from Tests with Fan 12in from Turbine ...................................... 53
Figure 3-40: Output Power Calculated from Tests Taken with Fan 12in from Turbine ............................. 54
Figure 3-41: Efficiency Calculated from Tests Taken with Fan 12in from Turbine .................................. 54
Figure 3-42: Torque Taken from Tests with Fan 24in from Turbine.......................................................... 55
Figure 3-43: Rotational Velocity from Tests Taken with Fan 24in from Turbine ...................................... 56
Figure 3-44: Output Power Calculated from Tests Taken with Fan 24in from Turbine ............................. 57
Figure 3-45: Efficiency Calculated from Tests Taken with Fan 24in from Turbine .................................. 57
Figure A-1: Dimensioned Drawing for Turbine Shaft ................................................................................ 62
Figure A-2: Dimensioned Drawing of the Flanged Shaft Mount for the Turbine ...................................... 63
Figure A-3: Dimensioned Drawing of the Spoked Arm Wheel for the Turbine ......................................... 64
Figure A-4: Dimensioned Drawing of the Top Half of the Turbine Blade ................................................. 65
Figure A-5: Dimensioned Drawing of Bottom Half of the Turbine Blade ................................................. 66
Figure C-1: Torque Meter Calibration Sheet .............................................................................................. 88
Figure C-2: Torque Meter Spec Sheet ........................................................................................................ 89
Figure C-3: Tachometer Spec Sheet Side 1 ................................................................................................ 90
Figure C-4: Tachometer Spec Sheet Side 2 ................................................................................................ 91
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List of Tables
Table 2-1: Expected Torque Values ............................................................................................................ 12
Table 2-2: Wind Meter Calibration at 0.85in Oil ........................................................................................ 21
Table 3-1: Approximate Air Velocities in m/s ............................................................................................ 23
Table B-1: In Wind Tunnel with Generator, 0.55in Oil .............................................................................. 67
Table B-2: In Wind Tunnel with Generator, 0.6in Oil ................................................................................ 68
Table B-3: In Wind Tunnel with Generator, 0.65in Oil .............................................................................. 69
Table B-4: In Wind Tunnel with Generator, 0.7in Oil ................................................................................ 70
Table B-5: In Wind Tunnel with Generator, 0.75in Oil .............................................................................. 71
Table B-6: In Wind Tunnel with Generator at 0.8in Oil ............................................................................. 72
Table B-7: In Wind Tunnel with Generator at 0.85in Oil ........................................................................... 73
Table B-8: In Wind Tunnel with Generator at 0.9in Oil ............................................................................. 74
Table B-9: In Wind Tunnel with Generator at 0.95in Oil ........................................................................... 75
Table B-10: In Wind Tunnel with Generator at 1in Oil .............................................................................. 76
Table B-11: In Wind Tunnel with Generator Averages .............................................................................. 77
Table B-12: In Wind Tunnel with Torque Meter, Test 1 ............................................................................ 77
Table B-13: In Wind Tunnel with Torque Meter, Test 2 ............................................................................ 78
Table B-14: In Wind Tunnel with Torque Meter, Test 3 ............................................................................ 79
Table B-15: Out of Wind Tunnel with Torque Meter at 12in, Test 1 ......................................................... 80
Table B-16: Out of Wind Tunnel with Torque Meter at 12in, Test 2 ......................................................... 81
Table B-17: Out of Wind Tunnel with Torque Meter at 12in, Test 3 ......................................................... 82
Table B-18: Out of Wind Tunnel with Torque Meter at 12in, Test 4 ......................................................... 83
Table B-19: Out of Wind Tunnel with Torque Meter at 24in, Test 1 ......................................................... 84
Table B-20: Out of Wind Tunnel with Torque Meter at 24in, Test 2 ......................................................... 85
Table B-21: Out of Wind Tunnel with Torque Meter at 24in, Test 3 ......................................................... 86
x
Table B-22: Out of Wind Tunnel with Torque Meter at 24in, Test 4 ......................................................... 87
Table C-1: Wind Meter Calibration at 0.425in Oil ..................................................................................... 92
Table C-2: Wind Meter Calibration at 0.5in Oil ......................................................................................... 93
Table C-3: Wind Meter Calibration at 0.65in Oil ....................................................................................... 94
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Nomenclature
APr: Projected area of the turbine
I: Current
P: Pressure
Patm: Atmospheric Pressure
PT: Power from Turbine
PW: Wind Power
R: Resistance
T: Torque
V: Voltage
VW: Wind Velocity
∆P: Pressure Difference
η: Efficiency
ρ: Air Denisty
ω: Rotational Velocity
1
Chapter 1
1.1 Introduction
Wind turbines are a growing area of interest in the energy market. With the push for the development of
green energy sources to reduce our dependence on fossil fuels such as coal, natural gas and oil, major
developments in the area of wind energy have been made in recent years. Many of the more well known
applications for wind energy are for large scale electric generation, with the commonly seen three bladed
turbines that can be seen in many windy areas. However, these types of turbines are not suited for
applications where the turbine needs to be portable or operate in low air speed areas.
Professor Alexander Gorlov developed a helical turbine designed for low fluid flow rates in the 1990’s. It
was initially developed for use in water, either in a slow river or as a tidal generator. The turbine, which
uses a vertical axis configuration, has three blades that are swept along a helical path. With this
configuration, the turbine will always rotate in the same direction, regardless of the direction of the fluid
flow. With its small size and intended use for low flow situations, Gorlov’s helical turbine is a prime
candidate to fill the need for a portable wind turbine.
The efficiency of a turbine, the ratio of the output electrical power compared to the input wind power, is
often used to determine how effective a given design is. The wind power can be determined using the
projection area of the turbine and wind velocity, in the equation
PW=0.5ρAPrV3W
2
The efficiency of the turbine is defined as follows
η=PT/PW
1.2 Literature Review
Gorlov’s helical turbine is based off the Darrius turbine which was invented in 1926 by G.J.M. Darrius
and was patented in the US in 1931 (1). Darrius’ turbine is commonly seen with semi-circular blades
with an airfoil cross section spaced evenly around then shaft with the ends of the blades meeting near
each end of the shaft. A drawing of this common configuration, taken from his patent, can be seen below
in Figure 1-1. In his patent, Darrius claims that his design is an improvement over previous transverse
axis designs because his blades use airfoils which offer minimal resistance to forward movement in the
fluid and thus converting the maximum amount of available energy in the fluid to usable energy by way
of the shaft.
Figure 1-1: Figure 3 from Darrius' Patent for his Turbine. (1)
In his paper on the Limits of the Turbine Efficiency for Free Fluid Flow, Dr. Gorlov points out a
weakness in Darrius’ design. He states that due to the vibrations cause by the blades changing their angle
of attack during the rotation of the turbine, the turbine is prone to fatigue failure in its parts or joints (2).
3
Another invention that provided influence to Gorlov’s design was a water wheel invented in 1902 by
Austrian Gustav Marburg. While Marburg’s claims and focus are on methods of allowing the water
wheel to split, allowing a ship to pass through, it is stated that the blades have a spiral or helical turn to
render them more effective (3). Unlike Darrius’ turbine, the blades on Marburg’s water wheel are
designed to harness the energy of the fluid through resistance, as opposed to lift. Gorlov’s turbine
combines the use of airfoils on a transverse axis turbine with the helical path inspired by the drawings of
Marburg’s water wheel.
Dr. Gorlov has filed for two patents for his turbine. His turbine was first patented in 1995 and claimed to
be a turbine with transverse airfoil blades in a helical configuration such that a portion of the blades were
always perpendicular to the flow, maintaining maximum thrust and a constant rotational velocity (4). In
the patent, hydro-pneumatic, hydro, wind and wave power systems are mentioned as sources of fluid flow
suitable for this design. Furthermore, there are statements suggesting that for gas turbine applications
under a low head pressure flow, the turbine can achieve similar rotational velocities to conventional
industrial generators, but with a higher efficiency.
The other patent filed for Gorlov’s turbine is designed to protect additional uses for the technology that
were not originally covered in the first filing. The focus of the second patent is for using the turbine to
directly drive a propulsion system (5). This patent shows the versatility of the devise and its applications.
Aside from directly driving a propulsion device, uses such as lift and lowering objects in a fluid are cited
as well.
4
Dr. Gorlov also describes the advantages of his turbine in papers he published detailing some of his
experimental results. In a paper published around the same time his patent on the turbine was granted,
Dr. Gorlov describes the design in detail and results from tests he conducted. Among his claims and
descriptions, he states that the power output will increase with the diameter of the turbine while the flow,
the size and the shape of the blades remains the same (6). The paper also lists the results of two
investigations. In all three, the helical turbine was compared to a Darrius type turbine.
For the first investigation, the turbines were tested in conditions where there was a “significant difference
in elevation across the turbine.” For that test, the Gorlov turbine was found to be 27 percent more
efficient and to have a rotational velocity 41 percent faster than the Darrius turbine. The second
investigation concerned the two turbines where they were only the velocity head was being extracted by
the turbine. In this case, the Gorlov turbine was found to be 33 percent more efficient and 27 percent
faster than the Darrius type. Dr. Gorlov goes on to claim that in low flow conditions that his turbine is 95
percent more efficient and 49 percent faster than Darrius’ (6).
In Gorban et al., the turbine’s unconstrained performance is claimed to be 35 percent (2). The paper itself
focuses on mathematical models used to compute the performance of the turbine in a free flow situation.
The maximal efficiency obtained from these calculations was 0.30113 and this is the number that formed
the basis of my assumptions when selecting the instrumentation used for my investigations.
In a paper written by Howell et al., a small Darrius type turbine was tested in a wind tunnel and compared
to results from a computational model run in fluent. The primary purpose of this investigation was to
verify the computational model and thus the turbine tested wasn’t designed to necessarily the most
5
efficient, but to provide results that would be easy to measure, given their size constraints (7). The results
illustrate the pulsating nature of the Darrius type turbine as described by Dr. Gorlov in his papers and
patents regarding his helical turbine. The paper also concludes that the computational model and the
physical tests were in reasonably good agreement, considering the errors and uncertainties involved in
both the physical test and the computational model.
In an article that appeared in the March 2009 issue of Environmental Engineering, author Niel Wilks
gives an overview of research that was being conducted at the time exploring the noise of vertical axis
turbines. He found that researchers were finding that turbines that follow the vertical or transverse axis
design are quieter than the horizontal axis counterparts (8).
Steven Peace, in an article that appeared in the June 2004 issue of ASME’s Mechanical Engineering,
argues that the future of wind turbines is with vertical axis designs, which the Darrius and Gorlov turbines
both fall under. Peace argues that vertical axis turbines have fewer limitations than horizontal turbines
and thus can be built to have larger swept areas and take advantage of larger input powers (9).
6
Chapter 2
2.1 Overview of Experiment
The goal of the experiment was to test a helical turbine in a controlled environment, measure the output
power and compare that with the available wind power to find the efficiency of the turbine. To do this,
two methods of measuring the turbines power were employed. The first consisted of using a torque meter
to determine the output torque and a tachometer to measure the rotational velocity, in revolutions per
second, of the turbine. The power would be calculated by the following relationship.
PT=2πωT
The second method used to determine the output power was as small generator powering a small resistor
circuit. Using Ohm’s Law,
V=IR
And the electrical power relationship,
PT=VI
The output power could be determined.
PT=V2/R
To calculate the air power over the projected area of the turbine, the air velocity was required. To
measure the air velocity in the wind tunnel a pitot tube attached to an oil manometer was used. For tests
done outside the wind tunnel, a hand held wind meter was used.
7
2.2 Design and Construction of the Turbine
2.2.1 Overview of Design
The turbine used for the experiments had to fit several criteria. The primary concern was making the
turbine small enough to fit into the wind tunnel in Northeastern’s Richard’s Hall lab. The cross sectional
area of the test chamber on this wind tunnel perpendicular to the air flow measures 18.5 inches wide by
14 inches tall. Furthermore, the opening in the side of the test chamber that I would use to put the turbine
in measured 12 inches in diameter, so the turbine would also have to fit through that hole. With those
constraints and allowing for clearance between the turbine and the walls to reduce their effects on the
turbines performance, a projected area of 14 inches wide and 10 inches tall was settled on. An exploded
view of the assembly can be seen below in Figure 2-1.
Figure 2-1: Exploded View of Turbine Assembly
The two other main concerns were cost and weight. Due to the relatively small sized of the turbine, I
wanted to keep the turbine light to reduce losses and to use materials that were inexpensive. To
accomplish this, the turbine was constructed using plastics for the spoke arms and blades, aluminum for
8
the flanges and steel for the shaft. All of the solid models and drawings required for the production of
the turbine were created using SolidWorks.
2.2.2 Shaft Design
The shaft of the turbine consists of a single two foot length of steel measuring 3/8ths of an inch in
diameter. The use of steel over a lighter metal such as aluminum was based on the availability of
materials on McMaster-Carr where I sourced many of the materials and parts I needed to purchase. The
steel rod that was purchased for the shaft had a straightness tolerance of ±0.05 inches where none of the
aluminum rods had a tolerance given.
2.2.3 Flange Design
The flanges, as shown in Figure 2-2, are used to attach the spoke arms to the shaft were machined out of
aluminum. The primary reason for these flanges being separate pieces instead of being part of the spoke
arm was to reduce the amount of material required. The flanges have three bolt holes to attach them to
the spoke arm and a single threaded hole for a set screw to secure them along with the spoke arm to the
shaft.
9
Figure 2-2: Flange Design
2.2.4 Spoke Arm Design
The spoke arm component, shown in Figure 2-3, has three arms extending from the central hub of the part
with extended sections at the end of the arms to attach the turbine blades. The leading edges of the arms
were also rounded to reduce the drag of the arms. For material, ¼ inch polycarbonate was chosen and the
parts were machined using a CNC machine.
Figure 2-3: Spoke Arm Design
10
2.2.5 Blade Design
The turbine blades are the most important part of this design. They are 14 inches long and follow a
helical path with a 5 inch radius over a 60 degree arc. The cross section is a standard NACA 0018 air foil
with a 1.5 inch chord. Since the airfoil is symmetric along the chord, the mean camber line follows the
chord. The helical path that the blade follows is drawn along the midpoint of the camber line and the
blade is set at a 0 degree angle of attack. The profile of the airfoil is shown in Figure 2-4.
Figure 2-4: NACA0018 Airfoil Profile
The blades were produced using a 3D printer that built the blades up a layer at a time with ABS plastic.
Due to the size constraints of the printer, the blades had to be cut in half and then assembled. The
assembly was done with a combination of plastic cement and pins to strengthen the joint. Additionally,
the joint was cut in a step shape to increase the surface area for bonding. While the glue and pins created
a strong joint, the bending stresses on the blades during operation would be centered on the joint area due
to the distance from the supports. The blades were further reinforced with fiber glass sleeves and epoxy,
resulting in a stiff blade that showed no visible deformation during testing.
11
Figure 2-5: Top View of Turbine Blade
Figure 2-6: Side View of Turbine Blade
Figures 2-5 and 2-6 show the top and side views of the turbine respectively. The top view illustrates the
arc of the helix that the blade follows while the side view shows the angle and the location of the join
where the two blade halves meet. The pitch and radius of the helix was determined by the projected area
of the turbine, which is the area in which the flow of the fluid interacts with the turbine. This area is the
determined by the length and diameter of the turbine, in this case being 140in2. Figure 2-7 shows a close
up of a single blade half, detailing the step design of the cut.
12
Figure 2-7: Blade Half
2.3 Selection of Instrumentation
2.3.1 Torque Meter
The torque meter selected for the testing was the Himmelstein model MCRT-48201V(25-0) (shown in
Figure 2-8). The meter is designed for a maximum of 2.82Nm of torque and was selected using an
expected power output based on the efficiency claims made by Professor Gorlov.
Table 2-1: Expected Torque Values
Air
Velocity
Rotational
Velocity
Air
Power
Expected
Efficiency
Expected
Output
Expected
Torque
(m/s) (RPM) (W) (W) (Nm)
5 250 6.692 0.3 2.008 0.077
6 260 11.564 0.3 3.469 0.127
7 270 18.363 0.3 5.509 0.195
8 280 27.411 0.3 8.223 0.280
9 290 39.028 0.3 11.708 0.386
10 300 53.536 0.3 16.061 0.511
11 310 71.257 0.3 21.377 0.659
12 320 92.511 0.3 27.753 0.828
13 330 117.619 0.3 35.286 1.021
14 340 146.904 0.3 44.071 1.238
15 350 180.685 0.3 54.206 1.479
13
As shown in Table 2-1, the expected torque output ranges from 0.077Nm to 1.479Nm depending on the
air velocity. The rotational velocities used were very rough estimates, since there were no previous tests
of this turbine conducted in air to base them on. The expected torque ranges up to around half of the
maximum torque the meter could handle. To get a torque meter with a lower maximum torque would
have required going to their low range line of meters, which were considerably more expensive than
meter used. Even then, the highest capacity of them, the 2.825Nm model, would have to have been
chosen, since the next size down had a maximum torque rating of 1.412Nm, which is lower than the
maximum torque expected.
Figure 2-8: Himmelstein Torque Meter
The Himmelstein torque meter operates by measuring the change in resistance of strain gauges applied to
the shaft of the meter. The meter comes with software for use with the RS-232 output, or the output can
be read as analog with either a ± 5V or ± 10V signal. The computer software will convert the voltage
14
output into units chosen by the user. It also has options to record the data as well as tare and calibrate the
meter.
2.3.2 Tachometer
To measure the rotational velocity of the turbine, an LED tachometer was chosen. The device operates by
illuminating an LED and sends an electronic pulse every time the light from the LED is reflected back
onto the photo sensor. The pulses were counted and displayed in Hz on an oscilloscope.
Figure 2-9: LED Tachometer
Since a piece of the reflective material was placed on each blade, the oscilloscope will show three pulses
per revolution of the turbine (RPS times 3).
2.3.3 Generator
For the direct electrical power measurements, a small bicycle generator was used. The generator chosen
was rated at 3 Watts and 6V, due to early test results showing poor performance. The generator was
connected to power a simple circuit consisting of a 10 ohm resistor. The voltage drop across the resistor
was measured to calculate the power.
15
Figure 2-10: Generator
2.3.4 Pitot Tube and Manometer
To measure the air velocity in the wind tunnel, a pitot tube connected to a manometer. The manometer
used consists of a vertical tube and a reservoir containing oil with a specific gravity of 0.826. Behind the
tube is a ruler in inches that can be moved to zero the manometer. The top of the manometer tube is open
to the atmosphere, so the pressure difference read is,
∆P = |P - Patm|
2.3.5 Wind Meter
To measure the air velocity when testing outside the wind tunnel, a Kestrel 1000 Wind Meter was used.
This meter uses an impeller mounted on the unit to measure the air velocity, which is displayed digitally
on a screen in units of the users choosing. To get a reading, the user must simply hold the meter in the
flow and read the output.
16
Figure 2-11: Kestrel Wind Meter
2.4 Test Setup and Procedure
2.4.1 Layout of the Test Chamber
The test chamber of the wind tunnel is 23 inches from entrance to exit, 18.5 inches wide and 14 inches
tall. In each corner there is a curved piece of plastic that serves as a diffuser for the two placed near the
entrance and as a nozzle for the two placed near the exit of the test chamber. On the left side of the
chamber when facing the direction of the airflow, there is a small hole cut into the wall which is covered
by a plastic plate from the outside. One of the bearings for the turbine was inserted into the plate. The
other bearing was inserted into the door panel that covers the much larger hole cut into the right side of
the test chamber. Along the top of the chamber is a long cut out for the pitot tube assembly, which is on a
track mechanism that allows the pitot tube to be positioned anywhere along the length of the chamber at
almost any height. The tube is limited, however, to the center of the width. In the center of the bottom
plate, there is a small hole, into which the LED tachometer was mounted, pointing directly up. An
overhead view of the test chamber with its inlet, outlet, diffuser and nozzle, and a side view can be seen in
Figure 2-12.
17
Figure 2-12: Test Chamber Layout, Top Down View and Side View
Outside the test chamber a tripod with a bracket for mounting the torque meter was positioned in such a
way that when the torque meter was mounted on the bracket, the shaft of the torque meter would be in
line with the shaft of the turbine. For the tests involving the generator, the bracket and tripod was used
along with a block of wood and some nylon cord to secure the generator in place.
2.4.2 Wind Tunnel Tests
For the wind tunnel tests, the turbine is supported on each end by bearings set into the walls of the wind
tunnel. The pitot tube was positioned in front of the turbine in the center of the plane perpendicular to the
air flow. Reflective tape was placed on the blades of the turbine and the tachometer was mounted in a
hole on the bottom of the test chamber, pointing up at the turbine.
For the measurements taken with the torque meter, the meter was mounted on a tripod and coupled to the
shaft of the turbine and a 50g weight was hung over a pulley placed on the torque meters shaft to provide
some resistance. Figure 2-13 shows the turbine in the wind tunnel with the torque meter
tripod. Also visible is the LED tachometer extending from the bottom of the test chamber
Figure
For the measurements taken with the generator,
directly to the shaft of the turbine. The 10 ohm resistor was
the probes from the oscilloscope where attached on either side of the resistor.
18
shows the turbine in the wind tunnel with the torque meter
tripod. Also visible is the LED tachometer extending from the bottom of the test chamber
Figure 2-13: Torque Meter Configuration
For the measurements taken with the generator, as can be seen in Figure 2-14, the generator was coupled
directly to the shaft of the turbine. The 10 ohm resistor was connected in a circuit with the generator and
the probes from the oscilloscope where attached on either side of the resistor.
Figure 2-14: Generator Set Up
shows the turbine in the wind tunnel with the torque meter mounted on the
tripod. Also visible is the LED tachometer extending from the bottom of the test chamber.
the generator was coupled
connected in a circuit with the generator and
19
For the generator tests, the air flow in the wind tunnel was set to a steady velocity and the system was
allowed to come to a steady state. Once this state was reached, ten readings of the air velocity, rotational
velocity and output torque or voltage were taken with 3 minutes in between each reading. Also noted was
the ambient temperature and atmospheric pressure at the beginning of the test. This was repeated for
multiple air velocities.
For the tests with the torque meter, only a few ramp ups were performed before it was concluded that the
generator was going to yield better results in the wind tunnel. The ramp ups were chosen for these tests
due to the observation that for every test, the tare value to zero the torque meter was different and the
output of the torque meter was different, even for the same settings. For the ramps, the test was started at
a low air velocity and the turbine was allowed to stabilize. Once it reached a steady rotational velocity, a
reading was taken and the air velocity was then increased to the next air velocity and the turbine was
allowed to stabilize again.
2.4.3 Out of Wind Tunnel Tests
For the tests outside of the wind tunnel, the turbine was mounted between two tables of equal heights with
the bearings set into blocks of wood. The tachometer was mounted to the top of one of the blocks and
reflective tape was placed on the spoke arms of the turbine. For this setup, only the torque meter was
used and it was coupled directly to the turbine shaft with the same 20g weight over the pulley as the tests
inside the wind tunnel. The torque meter itself rested on the table used to support one of the mounting
blocks for the turbine. To provide air flow, a large fan was placed in front of the test rig and the handheld
wind meter was used to take velocity readings. The set up is illustrated in Figure 2-15.
20
Figure 2-15: Out of Wind Tunnel Set Up
Similar to the in wind tunnel tests, the system was allowed to stabilize and then 10 readings were taken
with an interval of 3 minutes between each reading. Since the fan used to provide the air flow only had
one speed, the test was repeated with the fan at varying distances from the turbine. The turbine was tested
with the fan 12in and 24in, measured from the screen on the front of the fan to the shaft of the turbine,
away.
2.4.4 Calibration Check on Handheld Wind Meter
Since the handheld wind meter used for the tests outside the wind tunnel didn’t come with any calibration
documentation, its accuracy was tested by comparing readings taken from it and the manometer at the
same time in the same flow. To do this, the wind meter was mounted in the wind tunnel with the impeller
as close to the pitot tube as possible. They were positioned in the center of the wind tunnel. Multiple
readings were taken at each air velocity over a period of time.
21
Table 2-2: Wind Meter Calibration at 0.85in Oil
Temperature © 26
Atmospheric Pressure (in Hg) 29.97
SG Oil 0.826
Air Density (kg/m^3) 1.180303
Reading Wind Meter Manometer M. Speed Percent
# m/s (in Oil) (m/s) Error
1 17.2 0.85 17.217 0.101
2 17.3 0.85 17.217 0.479
3 17.3 0.85 17.217 0.479
4 17.3 0.85 17.217 0.479
5 17.2 0.85 17.217 0.101
6 17.2 0.85 17.217 0.101
7 17.3 0.85 17.217 0.479
8 17.3 0.85 17.217 0.479
9 17.3 0.85 17.217 0.479
10 17.2 0.85 17.217 0.101
Average 17.26 0.85 17.217 0.328
The check was done at four different air speeds and it was found that the hand held wind meter did give
accurate readings. Table 2-2 shows the results from the test done at 0.85in oil in the manometer. The rest
of the calibration data can be seen in Appendix C. This test showed the smallest difference between the
manometer and the wind meter of the four tests performed. In this case the average error was 0.328%.
The error was calculated using the following equation.
%Error=|(Wind Meter – Manometer)/Manometer|*100
The main cause for the error was the resolution of the manometer which only had gradations in .1in
intervals. This meant that the height of the oil in the tube could only be read to the nearest .05in. With
22
that limitation in mind, the air speed shown on the wind meter was close to the speed calculated from the
manometer in all four cases.
23
Chapter 3
For the tests conducted in the wind tunnel, the air velocity is referred to in terms of inches of manometer
oil. Below, on Table 3-1, is an approximate conversion from in Oil to m/s. For this table, the temperature
and barometric pressure were assumed. In the actual tests, the values of the ambient temperature and
barometric pressure were recorded for use in calculating the specific air velocity and power for that test.
Table 3-1 is for reference to give an approximate idea of the air’s velocity in familiar units.
Table 3-1: Approximate Air Velocities in m/s
Manometer Temperature Barometer
Air
Density
Air
Velocity
in Oil °C in Hg kg/m^3 m/s
0.55 25 29.9 1.181 13.843
0.6 25 29.9 1.181 14.458
0.65 25 29.9 1.181 15.049
0.7 25 29.9 1.181 15.617
0.75 25 29.9 1.181 16.165
0.8 25 29.9 1.181 16.695
0.85 25 29.9 1.181 17.209
0.9 25 29.9 1.181 17.708
0.95 25 29.9 1.181 18.193
1 25 29.9 1.181 18.666
3.1 Wind Tunnel Tests with Generator
A majority of the testing in the wind tunnel was performed using the generator to measure the output
power. The main tests done using the generator consisted of taking multiple readings at the same air
speed. This was done at a manometer reading of 0.55in to 1in in 0.05in intervals with 10 readings taken
at each. The readings were then averaged for each interval. The tabulated raw data and calculated values
for output power and efficiency can be found in Appendix B.
24
3.1.1 Results from 0.55in Oil Test
Figure 3-1: Rotational Velocity at 0.55in Oil
The results from the test taken at 0.55in Oil in the manometer can be seen in Figures 3-1, 3-2 and 3-3.
The turbine rotated with a velocity around 3.36 revolutions per second (RPS), which was not a high
enough rate to get a meaningful voltage out of the generator used, which the output power and efficiency
results clearly show. The primary purpose of this test is that it shows that the generator needs to be
turning at a minimum rate that lies between the results of this test and the test performed at 0.60in Oil.
3.25
3.3
3.35
3.4
3.45
3.5
1 2 3 4 5 6 7 8 9 10
Ro
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Reading Number
Rotational Velocity at 0.55in Oil, Generator
Rotational Velocity
Average Velocity
25
Figure 3-2: Output Power at 0.55in Oil
Figure 3-3: Efficiency at 0.55in Oil
0
0.0001
0.0002
0.0003
0.0004
0.0005
0.0006
0.0007
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
ow
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(W)
Reading Number
Output Power at 0.55in Oil, Generator
Output Power
Average Output
0
0.00005
0.0001
0.00015
0.0002
0.00025
0.0003
0.00035
0.0004
0.00045
0.0005
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency at 0.55in Oil, Generator
Efficiency
Average Efficiency
26
3.1.2 Results from 0.60in Oil Test
Figure 3-4: Rotational Velocity at 0.6in Oil
The rotational velocity at 0.6in Oil, as shown in Figure 3-4, was slightly less than 2RPS faster than it was
at 0.55in Oil. This rotational velocity surpassed the minimum needed to be able to get the generator to
create a current. The output power, shown in Figure 3-5 was very stable, with only two points differing
from the rest. As such, the efficiency, shown in Figure 3-6 was in general close to its average for the test
as well.
5
5.05
5.1
5.15
5.2
5.25
5.3
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.6in Oil, Generator
Rotational
Velocity
Average
Velocity
27
Figure 3-5: Output Power at 0.6in Oil
Figure 3-6: Efficiency at 0.6in Oil
0.41
0.415
0.42
0.425
0.43
0.435
0.44
0.445
0.45
0.455
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
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(W)
Reading Number
Output Power at 0.6in Oil, Generator
Output Power
Average Output
0.255
0.26
0.265
0.27
0.275
0.28
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency at 0.6in Oil, Generator
Efficiency
Average Efficiency
28
3.1.3 Results from 0.65in Oil Test
Figure 3-7: Rotational Velocity at 0.65in Oil
The test conducted with the air velocity set at 0.65in Oil was, like the test conducted at 0.6in Oil,
relatively stable in terms of rotational velocity, output power and efficiency. The variations of the
rotational velocity, output power and efficiency as compared to their average over the whole test can be
seen in Figures 3-7, 3-8 and 3-9 respectively.
6.05
6.1
6.15
6.2
6.25
6.3
6.35
6.4
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.65in Oil, Generator
Rotational Velocity
Average Velocity
29
Figure 3-8: Output Power at 0.65in Oil
Figure 3-9: Efficiency at 0.65in Oil
0.59
0.595
0.6
0.605
0.61
0.615
0.62
0.625
0.63
0.635
0.64
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
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(W)
Reading Number
Output Power at 0.65in Oil, Generator
Output Power
Average Output
0.325
0.33
0.335
0.34
0.345
0.35
0.355
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency at 0.65in Oil, Generator
Efficiency
Average Efficiency
30
3.1.4 Results from 0.70in Oil Test
Figure 3-10: Rotational Velocity at 0.7in Oil
The test conducted at an air velocity of 0.7in Oil was relatively stable as well. The power measurements
only showed two points that differed from the rest while the rotational velocity measurements showed the
turbine maintaining a relatively consistent velocity. Figures 3-10, 3-11 and 3-12 show the results from
this test, comparing the individual readings to the average values of that test.
6.6
6.65
6.7
6.75
6.8
6.85
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.7in Oil, Generator
Rotational Velocity
Average Velocity
31
Figure 3-11: Output Power at 0.7in Oil
Figure 3-12: Efficiency at 0.7in Oil
0.67
0.68
0.69
0.7
0.71
0.72
0.73
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
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(W)
Reading Number
Output Power at 0.7in Oil, Generator
Output Power
Average Output
0.33
0.335
0.34
0.345
0.35
0.355
0.36
1 2 3 4 5 6 7 8 9 10
Eff
cie
ncy
(%
)
Reading Number
Efficiency at 0.7in Oil, Generator
Efficiency
Average Efficiency
32
3.1.5 Results from 0.75in Oil Test
Figure 3-13: Rotational Velocity at 0.75in Oil
Unlike the previous few tests, the test at 0.75in Oil showed more variation in the results. Throughout the
test, the rotational velocity varied more than in previous tests, and going from the higher end of the range
down to the lower end of the range and then back up again. The output power and efficiency show
similar variation during the first half of the test before leveling off during the second half. This variation
shows a weakness with the timing of the readings. With the readings spaced out as they were, there was
the chance that the point taken at the time of the reading was not indicative of the actual performance over
all.
The results from this can be seen in Figures 3-13, 3-14 and 3-15.
6.82
6.84
6.86
6.88
6.9
6.92
6.94
6.96
6.98
7
7.02
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.75in Oil, Generator
Rotational Velocity
Average Velocity
33
Figure 3-14: Output Power at 0.75in Oil
Figure 3-15: Efficiency at 0.75in Oil
0.73
0.74
0.75
0.76
0.77
0.78
0.79
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
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(W)
Reading Number
Ouptut Power at 0.75in Oil, Generator
Output Power
Average Output
0.325
0.33
0.335
0.34
0.345
0.35
0.355
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Effciency at 0.75in Oil, Generator
Efficiency
Average Efficiency
34
3.1.6 Results from 0.80in Oil Test
Figure 3-16: Rotational Velocity at 0.8in Oil
Like the test performed at 0.8in Oil, the test at 0.85in oil showed more variation in the output power and
efficiency calculations than the earlier tests, though the rotational velocity was relatively consistent. The
test further illustrates the fluctuations in power output from the generator.
The results of the test can be seen in Figures 3-16, 3-17 and 3-18.
7.1
7.12
7.14
7.16
7.18
7.2
7.22
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.8in Oil, Generator
Rotational Velocity
Average Velocity
35
Figure 3-17: Output Power at 0.8in Oil
Figure 3-18: Efficiency at 0.8in Oil
0.8
0.81
0.82
0.83
0.84
0.85
0.86
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
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(W)
Reading Number
Output Power at 0.8in Oil, Generator
Output Power
Average Output
0.325
0.33
0.335
0.34
0.345
0.35
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency at 0.8in Oil, Generator
Efficiency
Average Efficiency
36
3.1.7 Results from 0.85in Oil Test
Figure 3-19: Rotational Velocity at 0.85in Oil
The test at an air velocity of 0.85in Oil turned out to be the most consistent in terms of power output, with
only one point differing from the others, right at the end of the test, as seen in Figure 3-20. The rotational
velocity, Figure 3-19, is like the other tests and shows some variation, due to the method the oscilloscope
uses to count the pulses from the tachometer and display the frequency of them. The calculated efficiency
for each reading can be seen in Figure 3-21.
7.35
7.4
7.45
7.5
7.55
7.6
7.65
7.7
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.85in Oil, Generator
Rotational Velocity
Average Velocity
37
Figure 3-20: Output Power at 0.85in Oil
Figure 3-21: Efficiency at 0.85in Oil
0.94
0.95
0.96
0.97
0.98
0.99
1
1.01
1 2 3 4 5 6 7 8 9 10
Ou
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Reading Number
Output Power at 0.85in Oil, Generator
Output Power
Average Output
0.345
0.35
0.355
0.36
0.365
0.37
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency at 0.85in Oil, Generator
Efficiency
Average Efficiency
38
3.1.8 Results from 0.90in Oil Test
Figure 3-22: Rotational Velocity at 0.9in Oil
The rotational velocity, as seen in Figure 3-22, for the test conducted with an air velocity at 0.9in Oil
again displayed a range of values with a difference between the high and low value being around
0.16RPS. Like other tests, this can mostly be attributed to the oscilloscopes error. The power and
efficiency calculations show variability during the early readings of the test and then level off for the last
five readings, as shown in Figures 3-23 and 3-24. The power fluctuation covers a rather significant range,
considering the scale of the output. This could indicate that either the turbine or the generator with its
resistor reaching a limit in their performance.
8.14
8.16
8.18
8.2
8.22
8.24
8.26
8.28
8.3
8.32
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.9in Oil, Generator
Rotational Velocity
Average Velocity
39
Figure 3-23: Output Power at 0.9in Oil
Figure 3-24: Efficiency at 0.9in Oil
0.94
0.96
0.98
1
1.02
1.04
1.06
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
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(W)
Reading Number
Output Power at 0.9in Oil, Generator
Output Power
Average Output
0.32
0.325
0.33
0.335
0.34
0.345
0.35
0.355
0.36
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Effciency at 0.9in Oil, Generator
Efficiency
Average Efficiency
40
3.1.9 Results from 0.95in Oil Test
Figure 3-25: Rotational Velocity at 0.95in Oil
At an air velocity of 0.95in, the rotational velocity, as seen in Figure 3-25, was less consistent than many
of the other tests conducted with this configuration. This observation goes over to the power and
efficiency results, shown in Figures 3-26 and 3-27 respectively, as well. The range that contains all of the
power calculations is almost as large as the range in the previous test.
8.7
8.75
8.8
8.85
8.9
8.95
9
9.05
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 0.95in Oil, Generator
Rotational Velocity
Average Velocity
41
Figure 3-26: Output Power at 0.95in Oil
Figure 3-27: Efficiency at 0.95in Oil
1.04
1.05
1.06
1.07
1.08
1.09
1.1
1.11
1.12
1.13
1.14
1 2 3 4 5 6 7 8 9 10
Ou
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Reading Number
Output Power at 0.95in Oil, Generator
Output Power
Average Output
0.325
0.33
0.335
0.34
0.345
0.35
0.355
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency at 0.95in Oil, Generator
Efficiency
Average Efficiency
42
3.1.10 Results from 1.0in Oil Test
Figure 3-28: Rotational Velocity at 1in Oil
The final test with the generator was conducted at an air velocity of 1in Oil. In Figure 3-28, it shows that
the rotational velocity again has a wide range of variation, though on average is about the same as it was
in the tests conducted at 0.95in Oil. The output power and efficiency, shown in Figures 3-29 and 3-30
respectively, show similar averages to the 0.95in Oil test as well, though a much smaller range of
variation.
8.65
8.7
8.75
8.8
8.85
8.9
8.95
9
9.05
1 2 3 4 5 6 7 8 9 10
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Reading Number
Rotational Velocity at 1in Oil, Generator
Rotational Velocity
Average Velocity
43
Figure 3-29: Output Power at 1in Oil
Figure 3-30: Efficiency at 1in Oil
1.04
1.05
1.06
1.07
1.08
1.09
1.1
1.11
1 2 3 4 5 6 7 8 9 10
Ou
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Reading Number
Output Power at 1in Oil, Generator
Output Power
Average Output
0.302
0.304
0.306
0.308
0.31
0.312
0.314
0.316
0.318
0.32
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency at 1in Oil, Generator
Efficiency
Average Efficiency
44
3.1.11 Rotational Velocity Results
In general, the rotational velocity of the turbine rose as the air speed in the wind tunnel increased, though
the rate of increase was not constant and reached a plateau at 0.95in Oil. Figure 3-31 shows the averaged
rotational velocity from each wind velocity that the static test was conducted at.
Figure 3-31: Rotational Velocity of the Turbine Across all Wind Velocities.
At each speed however, there was some variation in rotational velocity over the course of a single test.
The percent error for each reading was determined by dividing the difference of the individual reading
and the average rotational velocity by the average rotational velocity. The average error ranged from an
average error of 0.433% at 0.8in Oil to 1.665% at 0.55in Oil. The error curve can be seen in Figure 3-32.
0
2
4
6
8
10
0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
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Wind Velocity (in Oil)
Rotational Velocity
Rotational Velocity
45
Figure 3-32: Percent Error
The primary source of the error seen in the rotational velocity is rounding errors made by the oscilloscope
used to read the output from the tachometer. When the oscilloscope is reading the rotational velocity, it
counts the number of pulses over a certain period of time and then divides that number by the time period
to give a reading in Hz. Depending on the time period used the number of pulses, even if they are
occurring at a regular rate, in that period may not be the same as the number of pulses in the previous time
period.
In the case of the higher error at the 0.55in Oil test point the turbine was observed to have an unstable
rotational velocity. If the air velocity in the wind tunnel was lower than 0.55in Oil, it was observed that
the turbine’s velocity would become visible more erratic as the air power to keep the turbine going in that
environment was just not there.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
Av
era
ge
Pe
rce
nt
Err
or
(%)
Air Velocity (in Oil)
Rotational Velocity Error
Rotational Velocity …
46
3.1.12 Turbine Power Results
The power readings from the generator were much more consistent, in that most readings on a given test
were the same with a few outliers, than the rotational velocity readings. The output power however, was
much lower than anticipated. With air power across the projected area of the turbine in excess of 300W at
the highest air velocity settings, the turbine put out just more than 1W in electrical power from the
generator. From initial assumptions, an output of 60W to 90W was expected at the top air velocities
based on the efficiency figures claimed by Professor Gorlov.
Figure 3-33: Output Power from Generator and Air Power
Figure 3-33 shows how the output power for the turbine changes as the air speed increases. As can be
seen, the air power increases following the path of a third order polynomial, which is based on how the air
power is calculated. It could be speculated that the output power would follow a similar path in an ideal
situation; however that is not the case here. Instead the output power follows a logarithmic patch,
reaching an asymptote at around 1W. The output for the first speed setting is omitted due to observation
that the rotational velocity at that setting was not enough to produce a meaningful voltage from the
generator.
0
50
100
150
200
250
300
350
400
0
0.15
0.3
0.45
0.6
0.75
0.9
1.05
1.2
0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
Air
Po
we
r (W
)
Ou
tpu
t P
ow
er
(W)
Air Velocity (in Oil)
Output and Air Power
Output Power
Air Power
47
The error with respect to the average output at each point was higher on average than the error for the
rotational velocity. The highest error was at 0.55in Oil where the average error was 51.429%. This is an
outlier since the generator at this air velocity was showing virtually no voltage. Outliers aside, the error
ranged from 0.942% at 0.85in Oil at the low point to 3.826% at 0.9in Oil at the high point. For the tests
that had lower average error, the error tended to be caused by a couple points being either higher or lower
than the others while a significant majority of the points were the same.
The average error over all the air velocities tested at, excluding the test at 0.55in Oil can be seen in Figure
3-34.
Figure 3-34: Output Power Error
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
Pe
rce
nt
Err
or
(%)
Air Velocity (in Oil)
Output Power Error
Output Power Error
48
3.1.13 Turbine Efficiency Results
The turbine efficiency in these tests was poor, managing just over 0.35% at best. This is well below the
expected 25% efficiency. Since the efficiency is calculated from the output power of the turbine and
compare to the power of the air over the projected area of the turbine which is constant, the efficiency has
the same error as the output power. Like the output power, the efficiency at 0.55in Oil is an outlier due to
the fact that the generator used to measure the power was not producing a significant voltage at that
velocity.
Figure 3-35: Efficiency
Figure 3-35 shows how the efficiency changes as the air velocity increases. As it can be seen, the
efficiency stays around the .33% to .35% range and then drops off as the air velocity reaches 1in Oil.
This follows the observations gained from the output power readings where the output power stagnated
once the air velocity reached 0.95in Oil.
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.6
0.6
5
0.7
0.7
5
0.8
0.8
5
0.9
0.9
5
1
Eff
icie
ncy
(%
)
Air Velocity (in Oil)
Efficiency
Efficiency
49
3.2 Wind Tunnel Tests with Torque Meter
Much of the early testing of the turbine in the wind tunnel was performed with the torque meter. As the
results from the generator show, the turbine performed much worse than expected. With the early results
with the torque meter, it was unclear whether or not the turbine was really performing that poorly or if
there was a problem with the instrumentation. It was these initial tests that spurred the use of the
generator as a way to check that the torque was indeed operating correctly. The generator confirmed that
the turbine was not performing as expected, though it was observed that at the same air velocities, more
power was being generated when the generator was used than when the torque meter was used. On
comparing rotational velocity readings, it was found that the turbine turned significantly slower when the
torque meter was attached than when the generator was attached. Another issue that was observed was
that for each test, the tare value for the torque meter was significantly different.
The few tests that were run with the torque meter in the wind tunnel were done as ramps, where the test
was started at a low air velocity and it was then ramped up at set intervals, with data taken at each point.
This method was used due to the changing tare value for the torque meter. The raw data and calculated
properties can be found tabulated in Appendix B
50
Figure 3-36: Output Power of Turbine using the Torque Meter and Generator
Figure 3-36 shows that with the torque meter, the measured output power is only half of what was
measured using the generator. Also note that the output power for the -0.0181 tare run with the torque
meter is noticeably higher than the -0.0143 and -0.0153 tare runs. In theory the output torque measured
should be roughly the same across all tests, since the tare sets the displayed value to zero before the test
begins. It was observed, however, the value of the tare was dependent, in some degree to the initial
position of the turbine, suggesting some imbalance either in the turbine or in the flexible coupler used to
couple the shafts to one another.
0
0.2
0.4
0.6
0.8
1
1.2
0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
Ou
tpu
t P
ow
er
(W)
Air Velocity (in Oil)
Output Power, Torque Meter vs. Generator
Tare: -0.0143
Tare: -0.0153
Tare: -0.0181
Generator
51
Figure 3-37: Rotational Velocity, Torque Meter vs. Generator
Figure 3-37 shows that with the torque meter in place, the turbine rotated at a much slower rate in the
wind tunnel than it did with the generator. This shows that there was significantly more resistance in the
torque meter set up than there was in the generator set up. Due to this, the data gathered from the
generator provides a much more accurate picture of what is going on.
3.3 Out of Wind Tunnel Test with Torque Meter
For the tests conducted outside the wind tunnel, the torque meter had to be used because the turbine did
not rotate at a high enough velocity to produce a measurable voltage drop across the resistor attached to
the generator. Like the tests using the torque meter conducted inside the wind tunnel, the varying tare
value caused some inconsistencies in the torque values read from the torque meter. However, the varying
0
1
2
3
4
5
6
7
8
9
10
0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
Ro
tati
on
al
Ve
loci
ty (
RP
S)
Air Velocity (in Oil)
Rotational Velocity, Torque Meter vs. Generator
Tare: -0.0143
Tare: -0.0153
Tare: -0.0181
Generator
52
rotational velocity given by the tachometer was the main source for the differences in the output power
shown.
3.3.1 Fan 12in from Turbine
The test was run four times with the fan placed 12in away from the turbine, with the torque meter being
zeroed at the beginning of each test. The measured air velocity was relatively consistent, ranging from
5m/s to 5.3m/s.
Figure 3-38: Torque from Tests Taken with Fan 12in from Turbine
Figure 3-38 shows how the torque varied with each test. The main correlation that can be derived is that
the torque values are dependent on the tare value of the torque meter at the time that the test was
performed. The reason the tare value has such a noticeable effect on the outcomes of these tests is due to
the extremely low output torques seen from this turbine. If the turbine was performing as expected, the
differences caused by the change in the tare would be a small percentage of the overall measured torque.
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
1 2 3 4 5 6 7 8 9 10
To
rqu
e (
Nm
)
Reading Number
Torque with Fan 12in from Turbine
Tare: -0.0136 Air: 5.2m/s
Tare: -0.0160 Air: 5.3m/s
Tare: -0.0166 Air: 5.2m/s
Tare: -0.0185 Air: 5m/s
53
Figure 3-39: Rotational Velocity Taken from Tests with Fan 12in from Turbine
Above in Figure 3-39, the rotational velocities measured in the tests can be seen. The rotational velocities
remained rather consistent across the tests which is expected, since the fan only had one speed setting and
remained in the same position for all four of the tests run.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
1 2 3 4 5 6 7 8 9 10
Ro
tati
on
al
Ve
loci
ty (
RP
S)
Reading Number
Rotational Velocity with Fan 12in from Turbine
Tare: -0.0136 Air: 5.2m/s
Tare: -0.0160 Air: 5.3m/s
Tare: -0.0166 Air: 5.2m/s
Tare: -0.0185 Air: 5m/s
54
Figure 3-40: Output Power Calculated from Tests Taken with Fan 12in from Turbine
Figure 3-41: Efficiency Calculated from Tests Taken with Fan 12in from Turbine
0
0.005
0.01
0.015
0.02
0.025
0.03
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
ow
er
(W)
Reading Number
Output Power with Fan 12in from Turbine
Tare: -0.0136 Air: 5.2m/s
Tare: -0.0160 Air: 5.3m/s
Tare: -0.0166 Air:5.2m/s
Tare: -0.0185 Air: 5m/s
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency with Fan 12in from Turbine
Tare: -0.0136 Air: 5.2m/s
Tare: -0.0160 Air: 5.3m/s
Tare: -0.0166 Air: 5.2m/s
Tare: -0.0185 Air: 5m/s
55
The output power of the turbine in these tests can be seen in Figure 3-40 and the efficiency in Figure
3-41. Both calculated properties follow the same curves as they are directly related to one another.
However, the output power results appear closer to each other since they do not take into account the
different measured air velocities. In theory, the measured air velocity should have been the same for each
test. In practice, getting the wind meter in the same exact position for every test proved impossible.
Since the reading taken from the meter was dependent on its position for each test when the air velocity
reading was taken, the measured values differ somewhat.
3.3.2 Fan 24in from Turbine.
The second set of tests performed with the turbine outside the wind tunnel were done with the fan
positioned 24in from the turbine. The air velocity during these tests was only slightly lower than it was
with the fan 12in from the turbine with the velocity for these tests ranging from 4.9m/s to 5.1m/s.
Figure 3-42: Torque Taken from Tests with Fan 24in from Turbine
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
1 2 3 4 5 6 7 8 9 10
To
rqu
e (
Nm
)
Reading Number
Torque with Fan 24in from Turbine
Tare: -0.0134 Air: 5.1m/s
Tare: -0.0145 Air: 5m/s
Tare: -0.0171 Air: 5.1m/s
Tare: -0.0173 Air: 4.9m/s
56
Figure 3-42 shows the torque measured from each test across all ten readings for each. As the figure
shows, the torque for all four tests remained relatively stable for the duration of each test and like the
previous tests done at 12in varied from test to test based on the tare value.
Figure 3-43: Rotational Velocity from Tests Taken with Fan 24in from Turbine
The rotational velocity, shown in Figure 3-43 is not as consistent across the four tests at 24in as it was
across the four tests at 12in.
Both the output power and efficiency, shown in Figures 3-44 and 3-45, show a much larger spread than
the tests at 12in. This is mainly a result of the less consistent rotational velocities measured during these
tests.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
1 2 3 4 5 6 7 8 9 10
Ro
tati
on
al
Ve
loci
ty (
RP
S)
Reading Number
Rotational Velocity with Fan 24in from Turbine
Tare: -0.0134 Air: 5.1m/s
Tare: -0.0145 Air: 5m/s
Tare: -0.0171 Air: 5.1m/s
Tare: -0.0173 Air: 4.9m/s
57
Figure 3-44: Output Power Calculated from Tests Taken with Fan 24in from Turbine
Figure 3-45: Efficiency Calculated from Tests Taken with Fan 24in from Turbine
0
0.005
0.01
0.015
0.02
0.025
1 2 3 4 5 6 7 8 9 10
Ou
tpu
t P
ow
er
(W)
Reading Number
Output Power with Fan 24in from Turbine
Tare: -0.0134 Air: 5.1m/s
Tare: -0.0145 Air: 5m/s
Tare: -0.0171 Air: 5.1m/s
Tare: -0.0173 Air: 4.9m/s
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
1 2 3 4 5 6 7 8 9 10
Eff
icie
ncy
(%
)
Reading Number
Efficiency with Fan 24in from Turbine
Tare: -0.0134 Air: 5.1m/s
Tare: -0.0145 Air: 5m/s
Tare: -0.0171 Air: 5.1m/s
Tare: -0.0173 Air: 4.9m/s
58
3.4 Conclusions
Overall, the turbine did not perform anywhere near what was expected at the outset of this investigation.
Results of 25% to 30% efficient would have fallen right in line with the claims made about the efficiency
of this design and results of around 20% efficient would have shown promise. Instead, the tests
conducted throughout this investigation, using multiple measurement techniques both in and out of the
controlled environment of the wind tunnel, returned results equal to roughly one hundredth of what was
anticipated.
The selection of the instrumentation used for the investigation was based on the claims laid out for the
helical turbine. When the initial results showed such low numbers, they called into question the accuracy
of the equipment being used, most prominently the torque meter. As the results show, the generator
backed up the results from the torque meter.
A primary observation with the torque meter was that at the range of torque that the turbine was
producing, the tare value which zeroed the torque meter at the beginning of the test had a significant
effect on the torque read. This has to do mainly with the output torque being so small compared to the
designed range of the torque meter. The torque meter was selected based on the assumptions made based
on claims made about the devise. A performance so far below what was expected was not anticipated
during the selection process for the instrumentation.
While studies have been made with this design as a hydro-turbine and returned some promising results,
the same can not be said for this design’s performance as an air turbine. The tests performed in this
investigation suggests that this design in impractical as an air turbine.
59
It is unclear what caused the far lower than expected results from this investigation. It is well known that
turbines with blades that are transverse to their axis of rotation can be efficient enough to be used
commercially (9), even though they do not necessarily use a helical design. Dr. Gorlov himself claims his
design is more efficient than those of the Darrius type. A company in England even produces a wind
turbine that is very similar to the designs specified by Dr. Gorlov (10).
Given this evidence, it can be concluded that the results of this investigation were not typical and more
must be done through further investigations to isolate what caused the poor performance of this
investigation.
3.5 Further Investigations
While the results from this investigation were not what were expected, there is still plenty of room for
further investigation. Possible investigations that can still be made are as follows.
1) Experiment with different angles of attack where the angle of attack is defined as the angle
between the chord line of the air foil and the tangent line of the point where the midpoint of the
chord line intersects the arc of the turbine. All the tests performed in this investigation were
conducted with blades set at a 0 degree angle of attack. An investigation to determine whether
or not varying the angle of attack has any effect on the performance of this design could still be
conducted.
2) Another idea would be to model the turbine in Fluent or another computational program and see
if the results from that confirm the results this study showed using both a torque meter and a
generator.
60
3) Use a larger turbine in open air with a more powerful fan driving it. A larger turbine will result
in a larger, easier to measure output.
4) Test the turbine in wind tunnel with a larger test section to reduce the effects that the walls of
the wind tunnel might have, but maintain the controlled environment.
These are only some ideas of what can still be done. While this study suggests that the helical turbine
based on the design proposed by Dr. Gorlov is not practical as an air turbine, it is also not enough to
prove it either. Further tests and investigations should be performed.
61
Works Cited
1. Darrius, Georges Jean Marie. Turbine Having its Rotating Shaft Transverse to the Flow of the
Current. 1,835,018 United States of America, December 8, 1931.
2. Gorban, Alexander N., Gorlov, Alexander M. and Silantyev, Valentin M. Limits of the Turbine
Efficiency for Free Fluid Flow. s.l. : ASME, December 2001, Journal of Energy Resources Technology,
Vol. 123, pp. 311-317.
3. Marburg, Gustav. Submerged Water Wheel. 707,857 United States of America, April 21, 1902.
4. Gorlov, Alexander M. Unidirectional Helical Reaction Turbine Operable Under Reversible Fluid
Flow for Power Systems. 5,451,137 United States of America, September 19, 1995.
5. Gorlov, Alexander M. Helical Turbine Assembly Operable under Multidirectional Gas and Water
Flow for Power and Propulsion Systems. 6,155,892 United States of America, December 5, 2000.
6. Gorlov, Alexander M. The Helical Turbine: A New Idea for Low-Head Hydro. September 1995,
Hydro Review, pp. 44-50.
7. Howell, Robert, et al., et al. Wind Tunnel and Numerical Study of a Small Veritcal Axis Wind Turbine.
s.l. : Elsevier, 2010, Renewable Energy, Vol. 35, pp. 412-422.
8. Wilks, Neil. Wind City. Environmental Engineering. March 2009, pp. 24-25.
9. Peace, Steven. Another Approach to Wind. Mechanical Engineering. June 2004, pp. 28-31.
10. Quiet Revolution. [Online] [Cited: August 4, 2011.] http://www.quietrevolution.com/qr5-turbine.htm.
62
Appendix A: Technical Drawings of Turbine
Figure A-1: Dimensioned Drawing for Turbine Shaft
63
Figure A-2: Dimensioned Drawing of the Flanged Shaft Mount for the Turbine
64
Figure A-3: Dimensioned Drawing of the Spoked Arm Wheel for the Turbine
`
65
Figure A-4: Dimensioned Drawing of the Top Half of the Turbine Blade
66
Figure A-5: Dimensioned Drawing of Bottom Half of the Turbine Blade
67
Appendix B: Raw Data
Table B-1: In Wind Tunnel with Generator, 0.55in Oil
Temperature © 24.5 Width of Turbine (in) 10
Air Speed (in Oil) 0.55
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.83
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 13.8473149
Air Density (kg/m^3) 1.18071293
Air Power (W) 141.581496
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 9.815 0.04 3.272 0.00016 0.000113 2.701 64.286 64.286
2 10.05 0.08 3.350 0.00064 0.000452 0.372 42.857 42.857
3 10.22 0.08 3.407 0.00064 0.000452 1.314 42.857 42.857
4 10.25 0.08 3.417 0.00064 0.000452 1.611 42.857 42.857
5 9.909 0.04 3.303 0.00016 0.000113 1.770 64.286 64.286
6 10.03 0.08 3.343 0.00064 0.000452 0.570 42.857 42.857
7 9.889 0.04 3.296 0.00016 0.000113 1.968 64.286 64.286
8 10.44 0.08 3.480 0.00064 0.000452 3.494 42.857 42.857
9 9.992 0.04 3.331 0.00016 0.000113 0.947 64.286 64.286
10 10.28 0.08 3.427 0.00064 0.000452 1.908 42.857 42.857
Average: 10.0875 0.064 3.3625 0.000448 0.0003164 1.665 51.429 51.429
68
Table B-2: In Wind Tunnel with Generator, 0.6in Oil
Temperature © 24 Width of Turbine (in) 10
Air Speed (in Oil) 0.6
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.83
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 14.45089
Air Density (kg/m^3) 1.1827007
Air Power (W) 161.1848
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 15.39 2.04 5.130 0.416 0.258 0.997 1.182 1.182
2 15.8 2.08 5.267 0.433 0.268 1.640 2.732 2.732
3 15.39 2.04 5.130 0.416 0.258 0.997 1.182 1.182
4 15.42 2.04 5.140 0.416 0.258 0.804 1.182 1.182
5 15.66 2.04 5.220 0.416 0.258 0.740 1.182 1.182
6 15.51 2.04 5.170 0.416 0.258 0.225 1.182 1.182
7 15.8 2.12 5.267 0.449 0.279 1.640 6.721 6.721
8 15.22 2.04 5.073 0.416 0.258 2.091 1.182 1.182
9 15.62 2.04 5.207 0.416 0.258 0.482 1.182 1.182
10 15.64 2.04 5.213 0.416 0.258 0.611 1.182 1.182
Average: 15.545 2.052 5.182 0.421 0.261 1.023 1.891 1.891
69
Table B-3: In Wind Tunnel with Generator, 0.65in Oil
Temperature © 23.5 Width of Turbine (in) 10
Air Speed (in Oil) 0.65
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.83
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 15.0282969
Air Density (kg/m^3) 1.1846951
Air Power (W) 181.593945
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 18.59 2.44 6.197 0.595 0.328 0.423 0.987 0.987
2 18.53 2.44 6.177 0.595 0.328 0.745 0.987 0.987
3 18.56 2.44 6.187 0.595 0.328 0.584 0.987 0.987
4 18.26 2.44 6.087 0.595 0.328 2.191 0.987 0.987
5 18.59 2.44 6.197 0.595 0.328 0.423 0.987 0.987
6 18.77 2.44 6.257 0.595 0.328 0.541 0.987 0.987
7 19.05 2.52 6.350 0.635 0.350 2.041 5.612 5.612
8 18.9 2.48 6.300 0.615 0.339 1.237 2.286 2.286
9 18.67 2.44 6.223 0.595 0.328 0.005 0.987 0.987
10 18.77 2.44 6.257 0.595 0.328 0.541 0.987 0.987
Average: 18.669 2.452 6.223 0.601 0.331 0.873 1.580 1.580
70
Table B-4: In Wind Tunnel with Generator, 0.7in Oil
Temperature © 23 Width of Turbine (in) 10
Air Speed (in Oil) 0.7
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.83
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 15.582445
Air Density (kg/m^3) 1.1866963
Air Power (W) 202.77383
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 20.05 2.68 6.683 0.718 0.354 0.772 0.892 0.892
2 19.92 2.64 6.640 0.697 0.344 1.415 2.097 2.097
3 20.42 2.68 6.807 0.718 0.354 1.059 0.892 0.892
4 20.1 2.68 6.700 0.718 0.354 0.525 0.892 0.892
5 20.49 2.68 6.830 0.718 0.354 1.406 0.892 0.892
6 20.24 2.68 6.747 0.718 0.354 0.168 0.892 0.892
7 20.1 2.6 6.700 0.676 0.333 0.525 5.041 5.041
8 20.05 2.68 6.683 0.718 0.354 0.772 0.892 0.892
9 20.41 2.68 6.803 0.718 0.354 1.010 0.892 0.892
10 20.28 2.68 6.760 0.718 0.354 0.366 0.892 0.892
Average: 20.206 2.668 6.735 0.712 0.351 0.802 1.428 1.428
71
Table B-5: In Wind Tunnel with Generator, 0.75in Oil
Temperature © 22 Width of Turbine (in) 10
Air Speed (in Oil) 0.75
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.81
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 16.1074954
Air Density (kg/m^3) 1.18992064
Air Power (W) 224.57816
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 20.96 2.8 6.987 0.784 0.349 0.614 4.109 4.109
2 20.58 2.76 6.860 0.762 0.339 1.210 1.156 1.156
3 20.53 2.72 6.843 0.740 0.329 1.450 1.755 1.755
4 21.01 2.76 7.003 0.762 0.339 0.854 1.156 1.156
5 20.83 2.8 6.943 0.784 0.349 0.010 4.109 4.109
6 20.56 2.72 6.853 0.740 0.329 1.306 1.755 1.755
7 20.85 2.72 6.950 0.740 0.329 0.086 1.755 1.755
8 21.03 2.72 7.010 0.740 0.329 0.950 1.755 1.755
9 20.96 2.72 6.987 0.740 0.329 0.614 1.755 1.755
10 21.01 2.72 7.003 0.740 0.329 0.854 1.755 1.755
Average: 20.832 2.744 6.944 0.753 0.335 0.795 2.106 2.106
72
Table B-6: In Wind Tunnel with Generator at 0.8in Oil
Temperature © 21 Width of Turbine (in) 10
Air Speed (in Oil) 0.8
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.81
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 16.6075296
Air Density (kg/m^3) 1.19396799
Air Power (W) 246.986527
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 21.44 2.88 7.147 0.829 0.336 0.163 0.827 0.827
2 21.59 2.92 7.197 0.853 0.345 0.536 3.647 3.647
3 21.48 2.92 7.160 0.853 0.345 0.023 3.647 3.647
4 21.33 2.84 7.110 0.807 0.327 0.675 1.955 1.955
5 21.44 2.84 7.147 0.807 0.327 0.163 1.955 1.955
6 21.37 2.84 7.123 0.807 0.327 0.489 1.955 1.955
7 21.61 2.88 7.203 0.829 0.336 0.629 0.827 0.827
8 21.57 2.88 7.190 0.829 0.336 0.442 0.827 0.827
9 21.59 2.84 7.197 0.807 0.327 0.536 1.955 1.955
10 21.33 2.84 7.110 0.807 0.327 0.675 1.955 1.955
Average: 21.475 2.868 7.158 0.823 0.333 0.433 1.955 1.955
73
Table B-7: In Wind Tunnel with Generator at 0.85in Oil
Temperature © 22 Width of Turbine (in) 10
Air Speed (in Oil) 0.85
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.89
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 17.124775
Air Density (kg/m^3) 1.193114
Air Power (W) 270.59642
Reading
Raw
Rotational
Speed Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 22.48 3.08 7.493 0.949 0.351 0.496 0.523 0.523
2 22.4 3.08 7.467 0.949 0.351 0.850 0.523 0.523
3 22.12 3.08 7.373 0.949 0.351 2.089 0.523 0.523
4 22.32 3.08 7.440 0.949 0.351 1.204 0.523 0.523
5 22.79 3.08 7.597 0.949 0.351 0.876 0.523 0.523
6 22.94 3.08 7.647 0.949 0.351 1.540 0.523 0.523
7 22.87 3.08 7.623 0.949 0.351 1.231 0.523 0.523
8 22.62 3.08 7.540 0.949 0.351 0.124 0.523 0.523
9 22.34 3.08 7.447 0.949 0.351 1.115 0.523 0.523
10 23.04 3.16 7.680 0.999 0.369 1.983 4.711 4.711
Average: 22.592 3.088 7.531 0.954 0.352 1.151 0.942 0.942
74
Table B-8: In Wind Tunnel with Generator at 0.9in Oil
Temperature © 22 Width of Turbine (in) 10
Air Speed (in Oil) 0.9
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.89
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 17.62125
Air Density (kg/m^3) 1.193114
Air Power (W) 294.8203
Reading
Raw
Rotational
Speed Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 24.53 3.24 8.177 1.050 0.356 0.467 6.425 6.425
2 24.53 3.24 8.177 1.050 0.356 0.467 6.425 6.425
3 24.93 3.16 8.310 0.999 0.339 1.156 1.234 1.234
4 24.7 3.2 8.233 1.024 0.347 0.223 3.814 3.814
5 24.46 3.16 8.153 0.999 0.339 0.751 1.234 1.234
6 24.56 3.08 8.187 0.949 0.322 0.345 3.827 3.827
7 24.53 3.08 8.177 0.949 0.322 0.467 3.827 3.827
8 24.56 3.08 8.187 0.949 0.322 0.345 3.827 3.827
9 24.85 3.08 8.283 0.949 0.322 0.832 3.827 3.827
10 24.8 3.08 8.267 0.949 0.322 0.629 3.827 3.827
Average: 24.645 3.14 8.215 0.986 0.335 0.568 3.827 3.827
75
Table B-9: In Wind Tunnel with Generator at 0.95in Oil
Temperature © 22.5 Width of Turbine (in) 10
Air Speed (in Oil) 0.95
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.89
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 18.11945
Air Density (kg/m^3) 1.191095
Air Power (W) 319.9977
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 26.94 3.32 8.980 1.102 0.344 1.240 0.706 0.706
2 26.32 3.36 8.773 1.129 0.353 1.090 3.147 3.147
3 26.75 3.32 8.917 1.102 0.344 0.526 0.706 0.706
4 26.94 3.36 8.980 1.129 0.353 1.240 3.147 3.147
5 26.91 3.36 8.970 1.129 0.353 1.127 3.147 3.147
6 26.68 3.32 8.893 1.102 0.344 0.263 0.706 0.706
7 26.15 3.24 8.717 1.050 0.328 1.729 4.089 4.089
8 26.23 3.24 8.743 1.050 0.328 1.428 4.089 4.089
9 26.21 3.24 8.737 1.050 0.328 1.503 4.089 4.089
10 26.97 3.32 8.990 1.102 0.344 1.353 0.706 0.706
Average: 26.61 3.308 8.870 1.095 0.342 1.150 2.453 2.453
76
Table B-10: In Wind Tunnel with Generator at 1in Oil
Temperature © 22.5 Width of Turbine (in) 10
Air Speed (in Oil) 1
Width of Turbine (m) 0.254
Barometric Pressure (in Hg) 29.89
Length of Turbine (in) 14
Resistor (ohms) 10
Length of Turbine (m) 0.3556
Specific Gravity of Oil 0.826
Area of Turbine (m^2) 0.090322
Air Speed (m/s) 18.590161
Air Density (kg/m^3) 1.19109518
Air Power (W) 345.590177
Reading
Raw
Rotational
Velocity Voltage
Rotational
Velocity
Output
Power Efficiency
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
# RPS *3 V RPS W
1 26.04 3.28 8.680 1.076 0.311 1.665 0.231 0.231
2 26.37 3.24 8.790 1.050 0.304 0.419 2.199 2.199
3 26.12 3.24 8.707 1.050 0.304 1.363 2.199 2.199
4 26.65 3.32 8.883 1.102 0.319 0.638 2.691 2.691
5 26.54 3.32 8.847 1.102 0.319 0.223 2.691 2.691
6 26.18 3.24 8.727 1.050 0.304 1.137 2.199 2.199
7 26.6 3.24 8.867 1.050 0.304 0.449 2.199 2.199
8 26.48 3.24 8.827 1.050 0.304 0.004 2.199 2.199
9 26.82 3.32 8.940 1.102 0.319 1.280 2.691 2.691
10 27.01 3.32 9.003 1.102 0.319 1.998 2.691 2.691
Average: 26.481 3.276 8.827 1.073 0.311 0.918 2.199 2.199
77
Table B-11: In Wind Tunnel with Generator Averages
Manometer
Wind
Velocity Efficiency
Rotational
Velocity
Output
Power
Air
Power
Rotational
Velocity
Error
Output
Power
Error
Efficiency
Error
in Oil m/s RPS W W
0.55 13.847 0.000 3.363 0.000 141.581 1.665 51.429 51.429
0.6 14.451 0.261 5.182 0.421 161.185 1.023 1.891 1.891
0.65 15.028 0.331 6.223 0.601 181.594 0.873 1.580 1.580
0.7 15.582 0.351 6.735 0.712 202.774 0.802 1.428 1.428
0.75 16.107 0.335 6.944 0.753 224.578 0.795 2.106 2.106
0.8 16.608 0.333 7.158 0.823 246.987 0.433 1.955 1.955
0.85 17.125 0.352 7.531 0.954 270.596 1.151 0.942 0.942
0.9 17.621 0.334 8.215 0.986 294.820 0.568 3.827 3.827
0.95 18.119 0.342 8.870 1.094 319.998 1.150 2.453 2.453
1 18.590 0.311 8.827 1.073 345.590 0.918 2.199 2.199
Table B-12: In Wind Tunnel with Torque Meter, Test 1
Temperature © 26 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.78
Width of Turbine (m) 0.254
Resistor (g) 50
Length of Turbine (in) 14
Specific Gravity of Oil 0.826
Length of Turbine (m) 0.3556
Air Density (kg/m^3) 1.17282
Area of Turbine (m^2) 0.090322
Tare -0.0143
Reading Manometer
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power Air Velocity Air Power Efficiency
# in Oil RPS *3 Nm RPS W m/s W
1 0.6 3.421 0.0092 1.140 0.066 14.512 161.862 0.041
2 0.65 4.297 0.0096 1.432 0.086 15.104 182.511 0.047
3 0.7 5.023 0.0105 1.674 0.110 15.674 203.970 0.054
4 0.75 6.67 0.0115 2.223 0.161 16.224 226.209 0.071
5 0.8 7.716 0.0122 2.572 0.197 16.757 249.203 0.079
6 0.85 8.406 0.013 2.802 0.229 17.272 272.927 0.084
7 0.9 10.02 0.0132 3.340 0.277 17.773 297.360 0.093
8 0.95 10.76 0.0139 3.587 0.313 18.260 322.481 0.097
9 1 13.02 0.0149 4.340 0.406 18.734 348.272 0.117
78
Table B-13: In Wind Tunnel with Torque Meter, Test 2
Temperature © 26 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.78
Width of Turbine (m) 0.254
Resistor (g) 50
Length of Turbine (in) 14
Specific Gravity of Oil 0.826
Length of Turbine (m) 0.3556
Air Density (kg/m^3) 1.17282
Area of Turbine (m^2) 0.090322
Tare -0.0153
Reading Manometer
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Velocity
Air
Power Efficiency
# in Oil RPS *3 Nm RPS W m/s W
1 0.65 4.172 0.0102 1.391 0.089 15.104 182.511 0.049
2 0.7 5.125 0.0111 1.708 0.119 15.674 203.970 0.058
3 0.75 6.607 0.0118 2.202 0.163 16.224 226.209 0.072
4 0.8 7.985 0.0128 2.662 0.214 16.757 249.203 0.086
5 0.85 8.809 0.0137 2.936 0.253 17.272 272.927 0.093
6 0.9 10.07 0.0139 3.357 0.293 17.773 297.360 0.099
7 0.95 11.07 0.0145 3.690 0.336 18.260 322.481 0.104
8 1 13.21 0.0152 4.403 0.421 18.734 348.272 0.121
79
Table B-14: In Wind Tunnel with Torque Meter, Test 3
Temperature © 26 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.78
Width of Turbine (m) 0.254
Resistor (g) 50
Length of Turbine (in) 14
Specific Gravity of Oil 0.826
Length of Turbine (m) 0.3556
Air Density (kg/m^3) 1.17282
Area of Turbine (m^2) 0.090322
Tare -0.0181
Reading Manometer
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power Air Velocity
Air
Power Efficiency
# (in oil) RPS *3 Nm RPS W m/s W
1 0.6 2.064 0.0118 0.688 0.051 14.512 161.862 0.032
2 0.65 3.73 0.0132 1.243 0.103 15.104 182.511 0.057
3 0.7 5.294 0.0143 1.765 0.159 15.674 203.970 0.078
4 0.75 6.277 0.015 2.092 0.197 16.224 226.209 0.087
5 0.8 7.308 0.0164 2.436 0.251 16.757 249.203 0.101
6 0.85 7.932 0.0164 2.644 0.272 17.272 272.927 0.100
7 0.9 9.071 0.0171 3.024 0.325 17.773 297.360 0.109
8 0.95 11.15 0.0179 3.717 0.418 18.260 322.481 0.130
9 1 12.22 0.0181 4.073 0.463 18.734 348.272 0.133
80
Table B-15: Out of Wind Tunnel with Torque Meter at 12in, Test 1
Temperature © 25 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.83
Width of Turbine (m) 0.254
Air Density (kg/m^3) 1.1787319
Length of Turbine (in) 14
Tare -0.0136
Length of Turbine (m) 0.3556
Area of Turbine (m^2) 0.090322
Reading Distance
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power Efficiency
# in m/s RPS *3 Nm RPS W W
1 12 5.2 1.49 0.0039 0.497 0.012 7.485 0.163
2 12 5.2 1.418 0.0038 0.473 0.011 7.485 0.151
3 12 5.2 1.574 0.0038 0.525 0.013 7.485 0.167
4 12 5.2 1.446 0.0038 0.482 0.012 7.485 0.154
5 12 5.2 1.574 0.0039 0.525 0.013 7.485 0.172
6 12 5.2 1.72 0.0036 0.573 0.013 7.485 0.173
7 12 5.2 1.442 0.0036 0.481 0.011 7.485 0.145
8 12 5.2 1.687 0.0036 0.562 0.013 7.485 0.170
9 12 5.2 1.41 0.0036 0.470 0.011 7.485 0.142
10 12 5.2 1.372 0.0036 0.457 0.010 7.485 0.138
81
Table B-16: Out of Wind Tunnel with Torque Meter at 12in, Test 2
Temperature © 25 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.83
Width of Turbine (m) 0.254
Air Density (kg/m^3) 1.1787319
Length of Turbine (in) 14
Tare -0.016
Length of Turbine (m) 0.3556
Area of Turbine (m^2) 0.090322
Reading Distance
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power Efficiency
# in m/s RPS *3 Nm RPS W W
1 12 5.3 1.25 0.006 0.417 0.016 7.925 0.198
2 12 5.3 1.306 0.006 0.435 0.016 7.925 0.207
3 12 5.3 1.319 0.006 0.440 0.017 7.925 0.209
4 12 5.3 1.391 0.006 0.464 0.017 7.925 0.221
5 12 5.3 1.62 0.006 0.540 0.020 7.925 0.257
6 12 5.3 1.203 0.0062 0.401 0.016 7.925 0.197
7 12 5.3 1.558 0.0062 0.519 0.020 7.925 0.255
8 12 5.3 1.172 0.0062 0.391 0.015 7.925 0.192
9 12 5.3 1.214 0.0062 0.405 0.016 7.925 0.199
10 12 5.3 1.384 0.0062 0.461 0.018 7.925 0.227
82
Table B-17: Out of Wind Tunnel with Torque Meter at 12in, Test 3
Temperature © 26 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.82
Width of Turbine (m) 0.254
Air Density (kg/m^3) 1.1743958
Length of Turbine (in) 14
Tare -0.0166
Length of Turbine (m) 0.3556
Area of Turbine (m^2) 0.090322
Reading Distance
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power Efficiency
# in m/s RPS *3 Nm RPS W W
1 12 5.2 1.532 0.0062 0.511 0.020 7.457 0.267
2 12 5.2 1.545 0.0062 0.515 0.020 7.457 0.269
3 12 5.2 1.309 0.0062 0.436 0.017 7.457 0.228
4 12 5.2 1.26 0.0064 0.420 0.017 7.457 0.226
5 12 5.2 1.27 0.0064 0.423 0.017 7.457 0.228
6 12 5.2 1.395 0.0062 0.465 0.018 7.457 0.243
7 12 5.2 1.259 0.0064 0.420 0.017 7.457 0.226
8 12 5.2 1.572 0.0064 0.524 0.021 7.457 0.283
9 12 5.2 1.58 0.0066 0.527 0.022 7.457 0.293
10 12 5.2 1.618 0.0064 0.539 0.022 7.457 0.291
83
Table B-18: Out of Wind Tunnel with Torque Meter at 12in, Test 4
Temperature © 26 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.9
Width of Turbine (m) 0.254
Air Density (kg/m^3) 1.17754642
Length of Turbine (in) 14
Tare -0.0185
Length of Turbine (m) 0.3556
Area of Turbine (m^2) 0.090322
Reading Distance
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power Efficiency
# in m/s RPS *3 Nm RPS W W
1 12 5 1.262 0.0075 0.421 0.020 6.647 0.298
2 12 5 1.382 0.0077 0.461 0.022 6.647 0.335
3 12 5 1.589 0.0073 0.530 0.024 6.647 0.365
4 12 5 1.334 0.0073 0.445 0.020 6.647 0.307
5 12 5 1.436 0.0075 0.479 0.023 6.647 0.339
6 12 5 1.341 0.0073 0.447 0.021 6.647 0.308
7 12 5 1.568 0.0071 0.523 0.023 6.647 0.351
8 12 5 1.415 0.0073 0.472 0.022 6.647 0.325
9 12 5 1.652 0.0073 0.551 0.025 6.647 0.380
10 12 5 1.557 0.0071 0.519 0.023 6.647 0.348
84
Table B-19: Out of Wind Tunnel with Torque Meter at 24in, Test 1
Temperature © 25 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.91
Width of Turbine (m) 0.254
Air Density (kg/m^3) 1.1818931
Length of Turbine (in) 14
Tare -0.0134
Length of Turbine (m) 0.3556
Area of Turbine (m^2) 0.090322
Reading Distance
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power Efficiency
# in m/s RPS *3 Nm RPS W W
1 24 5.1 1.259 0.0013 0.420 0.003 7.080 0.048
2 24 5.1 1.671 0.0013 0.557 0.005 7.080 0.064
3 24 5.1 1.289 0.0011 0.430 0.003 7.080 0.042
4 24 5.1 1.241 0.0011 0.414 0.003 7.080 0.040
5 24 5.1 1.392 0.0011 0.464 0.003 7.080 0.045
6 24 5.1 1.671 0.0011 0.557 0.004 7.080 0.054
7 24 5.1 1.555 0.0011 0.518 0.004 7.080 0.051
8 24 5.1 1.341 0.0011 0.447 0.003 7.080 0.044
9 24 5.1 1.192 0.0011 0.397 0.003 7.080 0.039
10 24 5.1 1.319 0.0011 0.440 0.003 7.080 0.043
85
Table B-20: Out of Wind Tunnel with Torque Meter at 24in, Test 2
Temperature © 25 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.91
Width of Turbine (m) 0.254
Air Density (kg/m^3) 1.1818931
Length of Turbine (in) 14
Tare -0.0145
Length of Turbine (m) 0.3556
Area of Turbine (m^2) 0.090322
Reading Distance
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power Efficiency
# in m/s RPS *3 Nm RPS W W
1 24 5 1.763 0.0023 0.588 0.008 6.672 0.127
2 24 5 2.089 0.0021 0.696 0.009 6.672 0.138
3 24 5 1.85 0.0021 0.617 0.008 6.672 0.122
4 24 5 1.991 0.0021 0.664 0.009 6.672 0.131
5 24 5 1.849 0.0021 0.616 0.008 6.672 0.122
6 24 5 2.092 0.0021 0.697 0.009 6.672 0.138
7 24 5 1.8 0.0021 0.600 0.008 6.672 0.119
8 24 5 2.18 0.0021 0.727 0.010 6.672 0.144
9 24 5 2.026 0.0021 0.675 0.009 6.672 0.134
10 24 5 1.908 0.0021 0.636 0.008 6.672 0.126
86
Table B-21: Out of Wind Tunnel with Torque Meter at 24in, Test 3
Temperature © 25 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.9
Width of Turbine (m) 0.254
Air Density (kg/m^3) 1.1814979
Length of Turbine (in) 14
Tare -0.0171
Length of Turbine (m) 0.3556
Area of Turbine (m^2) 0.090322
Reading Distance
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power Efficiency
# in m/s RPS *3 Nm RPS W W
1 24 5.1 1.835 0.0047 0.612 0.018 7.078 0.255
2 24 5.1 2.178 0.0047 0.726 0.021 7.078 0.303
3 24 5.1 2.177 0.0047 0.726 0.021 7.078 0.303
4 24 5.1 2.057 0.0047 0.686 0.020 7.078 0.286
5 24 5.1 2.176 0.0047 0.725 0.021 7.078 0.303
6 24 5.1 2.06 0.0047 0.687 0.020 7.078 0.286
7 24 5.1 1.995 0.0047 0.665 0.020 7.078 0.277
8 24 5.1 2.131 0.0047 0.710 0.021 7.078 0.296
9 24 5.1 2.189 0.0047 0.730 0.022 7.078 0.304
10 24 5.1 1.852 0.0047 0.617 0.018 7.078 0.258
87
Table B-22: Out of Wind Tunnel with Torque Meter at 24in, Test 4
Temperature © 25 Width of Turbine (in) 10
Barometric Pressure (in Hg) 29.95
Width of Turbine (m) 0.254
Air Density (kg/m^3)
1.1834736
7
Length of Turbine (in) 14
Tare -0.0173
Length of Turbine (m) 0.3556
Area of Turbine (m^2)
0.09032
2
Reading
Distanc
e
Air
Velocity
Raw
Rotational
Velocity Torque
Rotational
Velocity
Output
Power
Air
Power
Efficienc
y
# in m/s RPS *3 Nm RPS W W
1 24 4.9 1.268 0.006 0.423 0.016 6.288 0.253
2 24 4.9 1.605 0.006 0.535 0.020 6.288 0.321
3 24 4.9 1.36 0.006 0.453 0.017 6.288 0.272
4 24 4.9 1.184 0.0058 0.395 0.014 6.288 0.229
5 24 4.9 1.141 0.006 0.380 0.014 6.288 0.228
6 24 4.9 1.489 0.0058 0.496 0.018 6.288 0.288
7 24 4.9 1.256 0.0058 0.419 0.015 6.288 0.243
8 24 4.9 1.123 0.0058 0.374 0.014 6.288 0.217
9 24 4.9 1.426 0.0056 0.475 0.017 6.288 0.266
10 24 4.9 1.695 0.0056 0.565 0.020 6.288 0.316
88
Appendix C: Calibration Information
Figure C-1: Torque Meter Calibration Sheet
89
Figure C-2: Torque Meter Spec Sheet
90
Figure C-3: Tachometer Spec Sheet Side 1
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Figure C-4: Tachometer Spec Sheet Side 2
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Table C-1: Wind Meter Calibration at 0.425in Oil
Temperature © 25
Atmospheric Pressure (in Hg) 29.97
SG Oil 0.826
Air Density (kg/m^3) 1.184264
Reading
Wind
Meter Manometer
M.
Speed Percent
# m/s (in Oil) (m/s) Error
1 12 0.425 12.154 1.285
2 12.3 0.425 12.154 1.185
3 12.2 0.425 12.154 0.375
4 12.2 0.425 12.154 0.375
5 12.2 0.425 12.154 0.375
6 12.3 0.425 12.154 1.185
7 12.3 0.425 12.154 1.185
8 12.3 0.425 12.154 1.185
9 12.3 0.425 12.154 1.185
10 12.3 0.425 12.154 1.185
Average 12.24 0.425 12.154 0.952
93
Table C-2: Wind Meter Calibration at 0.5in Oil
Temperature © 25.5
Atmospheric Pressure (in Hg) 29.97
SG Oil 0.826
Air Density (kg/m^3) 1.18228
Reading
Wind
Meter Manometer
M.
Speed Percent
# m/s (in Oil) (m/s) Error
1 13.5 0.5 13.194 2.266
2 13.5 0.5 13.194 2.266
3 13.6 0.5 13.194 2.984
4 13.5 0.5 13.194 2.266
5 13.5 0.5 13.194 2.266
6 13.5 0.5 13.194 2.266
7 13.5 0.5 13.194 2.266
8 13.5 0.5 13.194 2.266
9 13.5 0.5 13.194 2.266
10 13.5 0.5 13.194 2.266
Average 13.51 0.5 13.194 2.337
94
Table C-3: Wind Meter Calibration at 0.65in Oil
Temperature © 26
Atmospheric Pressure (in Hg) 29.97
SG Oil 0.826
Air Density (kg/m^3) 1.180303
Reading Wind Meter Manometer
M.
Speed Percent
# m/s (in Oil) (m/s) Error
1 15 0.65 15.056 0.375
2 15 0.65 15.056 0.375
3 15 0.65 15.056 0.375
4 15 0.65 15.056 0.375
5 15 0.65 15.056 0.375
6 15 0.65 15.056 0.375
7 15 0.65 15.056 0.375
8 15 0.65 15.056 0.375
9 15 0.65 15.056 0.375
10 15 0.65 15.056 0.375
Average 15 0.65 15.056 0.375