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WATER TURBINE CLASSIFICATION
Describing the main categories of water turbines and sorting them according
to their principles
Reaction and
Impulse Water
Turbines
By: Eng. Mo`tasem H. Y.
Abushanap
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Water Turbine Classifications:
1- Reaction water Turbines
2- Impulse water turbines.
1.1 Reaction water Turbines
a- Francis Turbines
b- Kaplan Turbines
c- Tyson
d- Gorlov
1.2 Impulse Water Turbine
a- Pelton Wheel
b- Turgo
c- Water wheel
d- Jonval Turbine
e- Archimedes Screw
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1.1 Reaction Turbines
1.1.1 Francis Turbines
It is an inward-flow reaction turbine that combines radial and axial flow concepts.
They operate in a head range of 10 to 650 meters (33 to 2,133 feet) and are primarily
used for electrical power production. The power output generally ranges from 10 to
750 megawatts, though mini-hydro installations may be lower. Runner diameters are
between 1 and 10 meters (3 and 33 feet). The speed range of the turbine is from 83 to
1000 rpm. Medium size and larger Francis turbines are most often arranged with a
vertical shaft. Vertical shaft may also be used for small size turbines, but normally
they have horizontal shaft.
1.1.2 Kaplan Turbines
a propeller-type water turbine which has adjustable blades. The Kaplan turbine was an evolution of the Francis turbine. Its invention allowed efficient power production in low-head applications
that was not possible with Francis turbines. The head ranges from 10-70 meters and the output from 5 to 120 MW. Runner diameters are between 2 and 8 meters. The range of the turbine is
Fig. 1.1.1.1, Side-view cutaway of a
Francis turbine
Fig. 1.1.1.2 Francis Inlet Scroll, Grand
Coulee Dam
Fig. 1.1.2.1, Vertical Kaplan Turbine
(courtesy Voith-Siemens).
Fig. 1.1.2.2, Vertical Kaplan Turbine
(courtesy VERBUND-Austrian Hydro
Power).
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from 79 to 429 rpm. Kaplan turbines are now widely used throughout the world in high-flow,
low-head power production.
1.1.3 Tyson
a hydropower system that extracts power from the flow of water. This design doesn't
need a casement, as it is inserted directly into flowing water. It consists of a propeller
mounted below a raft, driving a power system, typically a generator, on top of the raft
by belt or gear. The turbine is towed into the middle of a river or stream, where the
flow is the fastest, and tied off to shore. It requires no local engineering, and can
easily be moved to other locations.
1.1.4 Gorlov
Is a water turbine evolved from the Darrieus turbine design by altering it to have
helical blades/foils. The physical principles of the GHT work are the same as for its
main prototype, the Darrieus turbine, and for the family of similar Vertical axis wind
turbines which includes also Turbine wind turbine Quiet revolution wind turbine
Urban Green Energy. GHT, turbine and quiet revolution solved pulsatory torque
issues by using the helical twist of the blades.
Fig. 1.1.3.1 and Fig 1.1.3.2: Tyson Turbine
Fig. 1.1.4.1 and Fig 1.1.4.2: Gorlov Turbine
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1.2 Impulse Turbines
1.2.1 Water Wheel
is a machine for converting the energy of free-flowing or falling water into useful
forms of power. A water wheel consists of a large wooden or metal wheel, with a
number of blades or buckets arranged on the outside rim forming the driving surface.
Most commonly, the wheel is mounted vertically on a horizontal axle, but the tub or
Norse wheel is mounted horizontally on a vertical shaft. Vertical wheels can transmit
power either through the axle or via a ring gear and typically drive belts or gears;
horizontal wheels usually directly drive their load.
1.2.2 Pelton Wheel
Pelton wheels are the preferred turbine for hydro-power, when the available water source
has relatively high hydraulic head at low flow rates. Pelton wheels are made in all sizes.
There exist multi-ton Pelton wheels mounted on vertical oil pad bearings in hydroelectric plants. The largest units can be up to 200 megawatts. The smallest Pelton wheels are only a
few inches across, and can be used to tap power from mountain streams having flows of a
few gallons per minute. Some of these systems utilize household plumbing fixtures for water delivery. These small units are recommended for use with thirty meters or more of
head, in order to generate significant power levels. Depending on water flow and design,
Pelton wheels operate best with heads from 15 meters to 1,800 meters, although there is no
theoretical limit.
Fig. 1.2.1: Water Wheel
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1.2.3 Turgo
is an impulse water turbine designed for medium head applications. Operational
Turgo Turbines achieve efficiencies of about 87%. In factory and lab tests Turgo
Turbines perform with efficiencies of up to 90%. It works with net heads between 15
and 300 m.
1.2.4 Cross flow turbine
Unlike most water turbines, which have axial or radial flows, in a cross-flow turbine
the water passes through the turbine transversely, or across the turbine blades. As
with a water wheel, the water is admitted at the turbine's edge. After passing the
runner, it leaves on the opposite side. Going through the runner twice provides
additional efficiency. When the water leaves the runner, it also helps clean the
Fig. 1.2.2.1 Pelton Wheel
Fig. 1.2.3.1 Turgo turbine
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runner of small debris and pollution. The cross-flow turbine is a low-speed machine
that is well suited for locations with a low head but high flow.
1.2.5 Jonval Turbine
Water descends through fixed curved guide vanes which direct the flow sideways
onto curved vanes on the runner, This type is efficient at full gate, but at partial gate
it is less efficient than a Francis turbine. The usual orientation of the wheel was
horizontal and the first devices were even alternatively named as "horizontal water
wheels". However some sources mention turbines with both vertical and horizontal
shafts.
Fig. 1.2.4.1 Cross Flow Turbine
Fig. 1.2.5.1 Jonval Turbine
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References
Reaction Turbines
Francis
http://en.wikipedia.org/wiki/Francis_turbine
Kaplan
http://en.wikipedia.org/wiki/Kaplan_turbine
Tyson
http://en.wikipedia.org/wiki/Tyson_turbine
fig.1.1.3.1 http://permaculturewest.org.au/ipc6/ch08/shannon/index.html
fig.1.1.3.2 http://oneplusplus.com/AeroDynamic2/FreeFlowTech.html
Gorlov
http://en.wikipedia.org/wiki/Gorlov_helical_turbine
fig 1.1.4.1 http://www.climateandfuel.com/pages/tidal.htm
fig 1.1.4.2 http://www.symscape.com/blog/vertical_axis_wind_turbine
Impulse Turbines
Water wheel
http://en.wikipedia.org/wiki/Waterwheel
Pelton Wheel
http://en.wikipedia.org/wiki/Pelton_wheel
Turgo
http://en.wikipedia.org/wiki/Turgo_turbine
cross flow turbine
http://en.wikipedia.org/wiki/Banki_turbine
Jonval Turbine
http://en.wikipedia.org/wiki/Jonval_turbine
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extra resources
http://www.energybible.com/water_energy/water_turbines.html
http://permaculturewest.org.au/ipc6/ch08/shannon/index.html
