Keywords— Injection Pressure, Jatropha Oil Methyl Ester, Spray break up region, Injection velocity, Sauter Mean Diameter
Abstract— The spray characteristic of the injected fuel is mainly depends upon fuel injection
pressure, temperature, ambient pressure, fuel viscosity and fuel density. An experimental study
was conducted to examine the effect of injection pressure on the spray was injected into direct
injection (DI) diesel engine in the atmospheric condition. In Diesel engine, the window of 20 mm
diameter hole and the transparent quartz glass materials were used for visualizing spray
characteristics of combustion chamber at right angle triangle position. The varying Injection
pressure of 180 - 240 bar and the engine was hand cranked for conducting the experiments. Spray
characteristics for Jatropha oil methyl ester (JOME) and diesel were studied experimentally.
Spray tip penetration and spray cone angle were measured in a combustion chamber of Direct
Injection diesel engine by employing high speed Digital camera using Mie Scattering Technique
and ImageJ software. The study shows the JOME gives longer spray tip penetration and smaller
spray cone angle than those of diesel fuels. The Spray breakup region (Reynolds number, Weber
number), Injection velocity and Sauter Mean Diameter (SMD) were determined for diesel and
JOME. SMD decreases for JOME than diesel and the Injection velocity, Reynolds Number,
Weber Number Increases for JOME than diesel.
INTRODUCTION
Biodiesel is biodegradable, non-poisonous and eco-friendly fuel, produced from vegetable
oil, animal fats and waste cooking oil by transesterification process. The biodiesel blends is used
for reduce the fuel properties of viscosity and density. The improvement of the spray
characteristics leads to better atomization in the DI diesel engine.
The fuel flow in the injector and the fuel propagation of the nozzle outlet provides the
initial condition for investigate the macroscopic and microscopic spray characteristics in the
combustion chamber [1].Improve the accurate calculation and the breakup model of injection
spray is modified by introducing Kelvin–Helmholtz and Rayleigh–Taylor (KH–RT) model and
the Comparison of experimental results with numerical ones about spray shapes, mean droplet
diameter and axial mean velocity [2]. The macroscopic spray characteristics of spray tip
penetration and spray cone angle are determined by lateral cross-sections at 80% of the shadow
level and the lateral integration of shadow intensities of the diesel fuel [3]. The characteristics of
fuel spray for the fuel injector obtained by using the shadowgraphs and particle image
P. Raghu M. Senthamil Selvan K. Pitchandim N. Nallusamy
India. OMR, Kalavakkam–603 110, Tamil Nadu, Department of Mechanical Engineering, SSN College of Engineering,
[email protected] [email protected]
Sriperumbudur- 602 117, Pennalur Irungattukottai, Department of Mechanical Engineering, Sri Venkateswara College of Engineering,
Varying Injection Pressurable Energy Sources
Spray Characteristics of Diesel and Biodiesel by Experimental Study on Diesel Engine and Analysis the
Tamil Nadu, India.
International Conference on Recent Advances in Mechanical Engineering and Interdisciplinary Developments [ICRAMID - 2014]
ISBN 978-93-80609-17-1
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velocimetry at various chamber pressure conditions [4]. Comparison of oxidation stability for
biodiesel from different manufacturers and the storage conditions of biodiesel has been reported
[5].
\
Fig.1 Spray structure
In this work, the spray atomization was studied near nozzle tip to examine the effects of
injection pressure on spray characteristics for diesel and JOME under non evaporating conditions
for different injection pressure from 180 to 240 bar. Fig.1, illustrates the definition of spray tip
penetration and spray cone angle. Spray tip penetration indicates how far the spray travels in the
combustion chamber from the nozzle tip to spray end. This determines greatly the fuels
macroscopic distribution in the combustion chamber. This angle usually is between 5 and 30
degrees. The small droplet size represents the good atomization.
EXPERIMENTAL PROCEDURE
This experiment conducted in the modified single cylinder air cooled DI diesel engine.
This optical engine used for analyse spray characteristics. The experimental setup is shown in fig.
2. The fuel is supplied from the fuel tank to combustion chamber through the fuel filter and
pressure pump with fuel delivery pressure set at 180 to 240 bars. The whole experiments were
carried out at constant fuel injection timing at non-evaporating condition. The multi holes nozzle
(0.231 mm diameter) fuel injector was located on the side of the engine head. The injected fuel
was visualized by the optical window. The optical access to the combustion chamber is
accomplished from the side through a hole just beneath the cylinder head. There are two optical
windows arrested on the cylinder block with the help of flanges, which are used for visual
measurements and capturing the spray structure under various Injection pressure. The LED white
light source is used as illumination purpose for spray visualization. The 20 mm diameter hole
drill on the cylinder block in right angle triangle direction and arrested by quartz glass. Using this
fuel injection system, the fuel was injected into the combustion chamber and spray was captured
by a Sony cyber shot DSC-HX200V high speed digital Camera.
The high speed digital camera was located at 30 and placed one side of the optical
window to visualization for capture the spray structure and the LED light source is passed
through the other side of the optical window at exactly 90 for brightness. The both windows are
placed in right angle triangle direction. The camera was connected to a computing system with
the help of cable. Images are captured by using the camera and the images are taken in a multiple
shot mode or video mode for spray structure clearance. The captured images were further
processed using ImageJ software, which has graphical tools to analyse these captured images.
The macroscopic characteristics of spray tip penetration and spray cone angle were measured
from the captured images by Sony cyber shot DSC-HX200V high speed digital camera.
International Conference on Recent Advances in Mechanical Engineering and Interdisciplinary Developments [ICRAMID - 2014]
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Fig. 2 Experimental setup
Table 1. Engine specifications
Type Single cylinder ,vertical, air cooled 4-S CI engine
Engine Power (P) 4.4 kW
Engine Speed 1500 rpm
Bore Diameter (D) 87.5 mm
Stroke (L) 110 mm
Compression ratio 17.5:1
Table 2. Properties of neat diesel and JOME
Property Diesel Jatropha oil methyl ester
Density (kg/m3) 840 875
Viscosity(40 ) 3.4 4.27
Flash point ( ) 71 77
Fire point ( ) 103 270
Cetane number 48-56 51-52
RESULT AND DISCUSSION
The test fuels used for the investigations were JOME and diesel. Its properties were
shown in Table 2. The density and viscosity are the most important property which affects the
spray characteristics of fuel. Images are recorded for every injection pressure for diesel and
biodiesel by using the Sony cyber shot DSC-HX200V high speed digital Camera. The ImageJ
software was used for analyse the spray structure for varying the Injection pressure. The
macroscopic spray characteristics of spray tip penetration and spray cone angle were measured by
using the ImageJ software. The parameters like Injection velocity, Spray breakup region
(Reynolds Number, Weber Number) and Sauter mean diameter were determined for diesel and
JOME with increasing injection pressure.
Spray Structure for Diesel and Jatropha Oil Methyl Ester at Varying Injection Pressure
The images of diesel and Jatropha Oil Methyl Ester spray development are shown in
Fig.3.For various injection pressures. It is found that the fuel was ejected in a liquid column with
a larger mushroom shaped region at the injector tip. The five different images were taken to find
International Conference on Recent Advances in Mechanical Engineering and Interdisciplinary Developments [ICRAMID - 2014]
ISBN 978-93-80609-17-1
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out the macroscopic spray characteristics. First images are converting the 8 bit image. Then
change the image into black and white. Now fix the suitable threshold value to the image.
Fig. 3 The spray image for neat diesel and biodiesel at varying injection pressure
Spray Tip Penetration and spray cone angle
The spray tip penetration for JOME and diesel spray under various injection pressures is
shown in Fig. 4 It can be seen that JOME spray forms a longer tip penetration in comparison with
diesel at non evaporating condition, reason for that are high injection pressure and less
atomization of JOME. The less atomization of JOME has high viscosity and surface tension. This
leads to the higher spray tip penetration.
Fig.4 Variation of Injection pressure with spray tip penetration and spray cone angle for Diesel
and JOME
The spray cone angle for diesel and JOME spray under various injections pressure is shown in
Fig. 4. The higher injection pressure provides the high spray velocities and high injection flow
rates of JOME. This leads to a narrow spray cone angle. The high injection pressure eliminates
the effect of friction between JOME and nozzle surface due to high viscosity of JOME.
Injection Velocity
The Injection velocity for diesel and JOME spray under various injection pressures is
shown in Fig.5. The JOME have high viscosity and density so it has been low injection velocity
than diesel. The Injection velocity increases with increasing the injection pressure for both diesel
and JOME.
International Conference on Recent Advances in Mechanical Engineering and Interdisciplinary Developments [ICRAMID - 2014]
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Fig.5 Variation of Injection pressure with Injection Velocity for Diesel and JOME
Spray Breakup Region Reynolds Number and Weber Number is the Spray breakup region, which represent the
internal and external flow parameters of the spray. The spray Reynolds Number and Weber
Number for biodiesel and diesel spray under various injection pressures is shown in Fig.6. The
Reynolds Number and Weber Number both are increased for diesel and biodiesel with increasing
the injection pressure. The higher injection pressure leads to larger viscous forces and smaller
inertia forces. These provide a relatively large spray momentum for JOME. This leads to increase
the Reynolds Number and Weber Number for diesel.
Fig.6 Variation of Injection pressure with Reynolds Number and weber number for Diesel and
JOME
Sauter Mean Diameter The estimated value of Sauter Mean Diameter for JOME and diesel spray under various
Injection pressures is shown in Fig.7. The higher viscosity, density and surface tension are the
great responsible for larger values of SMD for JOME. So the JOME has greater SMD due to high
viscosity when compared to diesel. Whenever, increasing the injection pressure with decrease the
SMD value for both diesel and JOME because the small SMD value leads to better atomization.
Fig.7.Variation of Injection pressure with Sauter Mean Diameter for Diesel and JOME
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CONCLUSION
The experiments were carried out at different Injection pressure for diesel and JOME
Ester in a modified single cylinder air cooled DI diesel engine. The spray characteristics of spray
tip penetration and cone angle were measured under non-evaporating condition. The parameters
of Injection velocity, Breakup region (Reynolds number and Weber number) and SMD were
determined by varying the injection pressure from 180 to 240 bar. Spray tip penetration increases
with increasing the injection pressure for JOME because increase the fuel viscosity prevented the
breaking of spray jet, resulting in an increase the size of the spray droplets. Spray tip penetration
increases and cone angle decreases for JOME than diesel because the density and viscosity of
JOME is higher than the diesel fuel. Injection velocity of JOME is less than neat diesel because
the JOME have high viscosity and density. SMD is decreases for neat diesel than JOME with
increase in injection pressure. The high injection pressure is an effective way to improve the
atomization of diesel and JOME.
ACKNOWLEDGEMENT
The Authors would like to acknowledge the management of Sri Venkateswara College of
Engineering for the sincere help and providing the experimental setup to perform this research
work.
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