VIGNAN UNIVERSITY::VADLAMUDI
Expt No:
Date:
PELTON TURBINE
AIM: To determine the characteristic curve of pelton wheel under a constant head
and constant speed.
DESCRIPTION: Pelton Turbine is an impulse turbine, which is used to utilize high
heads for generation of electricity. All the available head is converted into velocity
energy by-means of spear and nozzle arrangement. The water leaves the nozzle in jet
formation. The jet of water then strikes the buckets of the pelton wheel runner. The
buckets are in the shape of double semi ellipsoidal cups, joined at the middle portion.
The jet strikes the knife-edge of the buckets with least resistance and shock. Then the
jet glides along the path of the cup, and the jet is deflected through more than 1600 to
1700. While passing along the buckets, the velocity of the water is reduced and hence
an impulsive force is supplied to the cups which in turn are moved and hence the shaft
is rotated. The specific speed of the pelton wheel changes from 10 to 100.
The pelton wheel is supplied with water under high pressure by a centrifugal
pump. The water is conveyed through venturimeter to the pelton wheel. The
venturimeter with manometer connection is used to determine the discharge of water
in the pipe. The nozzle opening can be decreased by operating the spear wheel at the
entrance side of turbine. The spear can be positioned in 5 places i.e. 1/5, 2/5, 3/5, 4/5,
5/5 of nozzle opening.
The turbine can be loaded by applying loads on the break drum.
The load at the entrance can be read by the pressure gauge.
The speed of the turbine can be measured with tachometer.
TECHNICAL SPECIFICATIONS:
1. TURBINE
1. Rated supply head
2. Discharge
3. Unit Speed
4. Specific speed
5. Runner outside Dia.
6. No. of pelton cups
7. Break drum diameter
-50 m
-660 1pm
-1500 rpm
-10 to 35
-300 mm
-20 Nos
-300 mm
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VIGNAN UNIVERSITY::VADLAMUDI
II.
SUPPLY PUMP
1. Rated head
-
2. Discharge
-750 1pm
3. Normal Speed
-2880 rpm
4. Power required
-15 Hp
5. Size
-3” x 21/2”
6. Type
III.
- High speed monoblock Centrifugal.
FLOW MEASURING UNIT
1. Size of venturimeter
-65 mm
2. Area ratio
-0.6
3. Throat diameter
-3.9 mm
4. Pressure gauge
-7kg / cm2
PROCEDURE:
(for constant head)
1. Prime the pump with water and start the pump.
2. Gradually open the delivery valve of the pump
3. Adjust the nozzle at 1/5 of the opening by operating the needle valve (spear) by
the hand wheel.
4. The head should be made constant by operating the delivery valve and the head
should be maintained at a constant value.
5. Observe the speed of the wheel using the tachometer.
6. Observe the reading h1 and h2 corresponding to the fluid level in the two
manometer limbs, which is connected to the venturimeter.
7. Adjust the load on the brake drum to vary the speed of the drum and record the
readings from the tachometer, weight added and spring balance.
8. Repeat step 7 for getting at least six sets of reading
9. Repeat the experiment for
2 3 4
, , and full opening of the nozzle.
5 5 5
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VIGNAN UNIVERSITY::VADLAMUDI
Experimental procedure (constant speed method)
1. Close the delivery valve of the pump.
2. Prime the pump with water and start the motor
3. Gradually open the delivery valve of the pump and adjust the nozzle at
1
of the
5
opening.
4. Read the pressure gauge and note down the value
5. Apply the load on the brake drum so that the speed shown by the tachometer
comes to the rated speed and note this rated speed. Note down the tension T1 and
T2 indicated by the spring balances attached to the brake drum.
6. Observe and note the readings of the manometer limbs
7. Manipulate the discharge through pressure valve and control the speed at the rated
value through hanger weights and note the reading of the spring balance.
8. Observe and note down the manometer reading h1 & h2.
2 3 4
, , and full opening of the nozzle.
5 5 5
9. Repeat the experiment for
CALCULATIONS:
s

Head of water h = hm  m 1 = 12.6 hm =____________________
 s

In manometer across venturimeter
Discharge of water = Q = K h m3 / sec.
Where
K = Constant of venturimeter
=
a1 a 2
a12  a 22
 2 g = _____________________
Where a1 = Area of cross section at the point of entry
a2 = Area of cross section at the constriction and in this case d2 /d1 = 0.6
and d1 = 0.065 m
hm = Pressure head in meters = (h1 – h2) meters= _____________
Sm = Specific gravity of mercury=__________
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VIGNAN UNIVERSITY::VADLAMUDI
S
BP =
= Specific gravity of fluid flowing (ie) water=__________________
2NT
60,000
KW
T = (W1 – W2)R=_______________________
R = radius of Brake drum =_________________
Where R
N
W1
W2
IP =
=
=
=
=
gQH
1000
m
rpm
Kg
kg
KW =
Where H = total water head in m of
Ginkgf / cm 2  10 4
water =
=______________
water
Where G is pressure gauge reading.
Ns = specific speed =
Nu = unit speed
Pu = unit power
=
N P
=_________________
H 5/ 4
N
Qu = unit discharge =Qu =
Efficiency,
=____________________
H
p
=
=__________________
H 3/ 2
Q
H
=_________________
 = BP / IP X100 = ______________ %
GRAPHS : 1. Speed Vs efficiency
2. Speed Vs BHP
3.Speed Vs Discharge
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