options for high head hydro sites design of strong and compact muscles for high specific energy...
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Options for High Head Hydro Sites
Design of Strong and Compact Muscles for High Specific
Energy …….
P M V SubbaraoProfessor
Mechanical Engineering Department
PlantOutlet
RunnerOutlet
RunnerInlet
InletTo Stator
g
V streammain
2
2
0absh
HH
StatorOutlet
hatm
Hydraulic Energy Diagram for A HEPPInlet To IntakeSystem
Conservation of Rothalpy for Incompressible Machines : Clues for High Head Hydro Station
In an ideal Penstock constant2
2
gHpV
p atmpenstock
static
In an ideal Nozzle constant2
2
jetstatic
Vp
In an ideal turbo-machine constant2
2
relstatic
Vp
constant2
1 22 gzUVp
bladerel
constant22
12
22 gzUVVp
gzUVp
bladebladerel
Options for High Head Sites
• High power with low volume flow rate is feasible.• A relatively high flow rate can be easily split into multiple
number of low specific speed jets.• Can produce high velocity jets/streams.• Pure and maximum change in direction of flow velocity is
feasible.• Invent a machine which absorbs energy by changing the
direction of a high velocity jet.• No variation of static pressure across machine. • Entire machine is exposed to atmospheric pressure.
Vri = Vai - Ub
Vre = -Vri
Ub
Vae = Vre +Ub
Vai
Analysis of Simple Moving Impulse Blade
baibbaibriae UVUUVUVV 2
bairirewhirl UVVVV 2
baiR
baiA
UVmVmF
UVmVmF
2
2
bbaib
bbRb
UUVmP
VUmUFP
2
Kinetic power lost by the jet :
bbai
bai
bai
UUVmKP
UVVm
KP
UVVm
VVm
KP
ai
aiaeai
2
22
222
22
2222
Power lost by jet = Power gained by the Blade
bbjetjetjetbbaib UUVVAUUVmP
22
PowerJet
Power BladeBlade Impulse pure of Efficiency
gH
UUgHblade
22
gH
DNDNgH
blade
606022
2
60
2 max..max
gHND
gHU eff
Pelton Turbine: The First Titled Impulse Turbine
• Lester Allan Pelton, considered to be the father of modern day hydroelectric power, was born in Vermilion Township, Erie County, in Ohio, on September 5, 1829.
• Pelton embarked on an adventure in search of gold.
• Shifted to California from Ohio in 1850, he was 21 years old.
• After a failed quest for gold, he joined in the gold mines as a millwright, and carpenter at Camptonville, Yuba County, California in 1864 .
Camptonville Gold Mine : Use of Hydro Power
• Water wheels were being used to provide mechanical power for all things mining, air compressors, pumps, stamp mills and operating other machines.
• The energy to drive these wheels was supplied by powerful jets of water which struck the base of the wheel with flat-faced vanes.
• These vanes eventually evolved into hemispherical cups, with the jet striking at the center of the cup on the wheel.
• Pelton observed that one of the water wheels appeared to be rotating faster than other similar machines.
• It turned out initially that this was due to the wheel had come loose, and moved a little on its axle.
Damaged Wheel is A Better Design
• He noticed the jet was striking the inside edge of the cups, and exiting the other side of the cup.
• His quest for improvement resulted in an innovation.
• Pelton reconstructed the wheel, with the cups off center only to find again that it rotated more rapidly.
• Pelton also found that using split cups enhanced the effect. By 1879 he had tested a prototype at the University of California, which was successful.
• He was granted his first patent in 1880.
• By 1890, Pelton turbines were in operation, developing thousands of horsepower, powering all kinds of equipment.
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