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HYDRAULIC TURBINE
BASIC HYDRAULICS
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ASSISTANT PROFESSOR
http://sites.unal.edu.co/a/bt.unal.edu.co/lddonadog
Leonardo David DONADO-GA
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CLASIFICATION
IMPULSE REACTION
http://www.youtube.com/watch?v=HzQPNpP55xQ&NR=17/29/2019 Turbinas - Donado
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PELTON WHEELS
So called in honor ofLester A. Pelton (1829-1908)
Patent in 1880 on animproved with a splitter in
the middle. W.A. Doble brought out
the ellipsoidal buccket,basis of the modern forms
http://www.youtube.com/watch?v=4vGeUmbvcDk&feature=fvw7/29/2019 Turbinas - Donado
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KAPLAN TURBINES
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THE HYDRAULIC IMPULSE TURBIN
HORIZONTAL Single Nozzle
Single-overhu
Double-overh
VERTICAL SHA
Multiple Nozz
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SETTINGS
www.geppert.at
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HEAD ON IMPULSE TURBINE
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HEAD ON IMPULSE TURBINE
22 2 2
2 1 2 2
1
1
1 1 2 2 2 2
= + = + +
B B
v
p V A V v Vh k
g C A g g
Where:C
vis the coefficient of velocity of the nozzle
A2
is the cross sectional flow area of the jet
A1 is the cross sectional flow area of the pipe upstream of the nozzleV1
is the velocity of jetv2
is the velocity of water relative to bucket at exit from bucketV2
is the absolute velocity of water leaving the bucketh is the energy head delivered to the bucketsk is the bucket friction loss coefficient [0.2 0.6]
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NOZZLES
In order to maintain a constant
speed of rotation Size can vary with the position of
the needle
Shape of both nozzle tip andneedle should cause a minimumfriction loss and avoid cavitation
damage The main idea is having all
particles of water moving inparallel lines, with no spreadingout.
2=jet VP Q
energy.saving.nu/hydroenergy/
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EXAMPLE
A 6-in-diameter pipe (f = 0.020) of lengthdelivers from a reservoir with a water-surfaceof 500 ft to a nozzle at elevation 300 ft. Ththe nozzle is used to drive a small impulse tthe head loss through the nozzle can be exp0.04 of the kinetic energy of the jet, findiameter that will result in maximum powerNeglect the head loss at entrance to the pipereservoir. Evaluate the power in the jet.
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HOMEWORK
How is regulated the
speed in an impulseturbine?
How are constructed thewheels?
How is determined thewheel diameter?
Efficiency variation withsize and head
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ACTION OF THE JET
Bucket velocity, u
Abs
Jet v
Relative
Bucket velocity, v1
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ACTION OF THE JET
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TORQUE AND POWER FOR IDEAL C
v2V2
u
V2= u + v
2
v1
V1
u
V1= u + v1
2 1 2 = = V V V
( ) 2 = =uF Q V
2= = u
DT F QD
1 20 180 = =
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TORQUE AND POWER FOR IDEAL C
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TORQUE AND POWER FOR IDEAL C
v2
V2
u
V2= u + v
2
v1
V1
u
V1= u + v
1
2
2
cos1
1
=
+ uF Q
k
2cos2 1
1
= +
h k
1 20 165 = =
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ACTUAL TORQUE AND POWER
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EXAMPLE
Find the torque and power transferredbuckets of an impulse wheel with 1=0, k= 0.44, =0.46, Cv=0.98, a jet diameterand a pitch diameter of 10 ft. Findhydraulic efficiency, and, expressedpercentage of the total head, find: the hebucket friction, the energy head lossdischarge, and the head loss in the nozzle.
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SPECIFIC SPEED
A turbine is to o
400 rpm under aof 1320 ft. If ain-diameter jetfind the specificthe machine
Cv=0.98, =0=0.85. Findrequired pitch dthe wheel.
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REACTION TURBINES
Francis
10 < Ns < 100
Radial-flow
Mixed-flow
Kaplan:
100 < Ns < 250
Axial-flow
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SPECIFIC SPEED
For a small power under high head a Peltwith its low specific speed is used torotative speed down to a suitable value, wlarge power under a low head a reactiowith its higher specific speed is used torotative speed to a suitable value.
A lot of possible combinations of N and P twith the fixed H.
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REACTION TURBINES
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REACTION TURBINES
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TUBE TURBINE
10 < h < 60Axial Flow
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SETTINGS
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DRAFT TUBES
Integral part of the
turbine and a desi Enable the turbine
above the tail watwithout losing any thereby
Reduce the head losubmerged discharthereby increase thavailable to the ru( ) 2 21 1 2
1
2 2
abs atmL
p p V Vz h
g g = + +
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DRAFT TUBES
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NET HEAD
22
2 2
CB BB
Vp Vh zg g
= + +
( ) ( )2 2
1 2 2
2 2
CV V V V h h k
g g
= +
O A ON A N S
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OPERATION AT DIFFERENT SP
For the inward-
Francis turbine
centrifugal acti
decreases the f
increasing whee
Francis: 0.7 <
Kaplan: 1.4
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