1. HYDRAULIC PUMPS & TURBINES
Prepared by
Deepak B
Assistant Professor
Department of Mechanical Engineering
MBCET,Trivandrum
2. HYDRAULIC PUMPS
• Hydraulic pump is a device which utilizes the mechanical energy to
raise the pressure head of a fluid. It raises liquid from a lower level to
higher level.
• Hydraulic pumps are usually used in agricultural and irrigation works,
municipal water supply and drainage systems, hydraulic pressure
machines etc.,
• Hydraulic pumps are generally classified into Positive displacement
pumps and Rotodynamic pumps
• Positive displacement pumps liquid is sucked and then pushed by
exerting force on it by a moving mechanical member, which results in
increasing the pressure and lifting the liquid by desired height. Eg:
Reciprocating pump
• Rotodynamic pump liquid passes through a rotating member called
impeller. Due to rotation angular momentum of liquid changes which
increases its pressure. The pressure developed enables the liquid to get
lifted to a higher level. Eg: Centrifugal pump.
4. CONTINUED…
• Suction head (hs): Height of center of pump from water level
• Delivery head (hd): Height of tank from center of pump
• Static head: Sum of suction and delivery head
• Manometric head: Head against which centrifugal pump has to work
!" = ℎ% + ℎ& + ℎ'% + ℎ'& +
()
*
+,
Water power = -./!"
Manometric efficiency (0man) =
1234"56789 :52&
;52& 8"<2765& => 8"<5??57 43 @2657
=
A2657 <4@57
<4@57 26 6:5 8"<5??57
Mechanical efficiency (ηmech) =
B4@57 26 6:5 8"<5??57
B4@57 26 6:5 %:2'6
Overall efficiency (η0) = 0man x ηmech =
A2657 <4@57
C:2'6 <4@57
7. RECIPROCATING PUMP
• Reciprocating pump is used in high head low discharge situations.
Discharge =
!"#
$%
Power delivered =
!"#
$%
&' ℎ) + ℎ+
Slip: It is the difference between
theoretical and actual discharge of a
reciprocating pump
Slip = ,-./01/-2345 − ,43-745
Percentage slip =
89:;<=;9>?@A B C@?9D@A
89:;<=;9>?@A
Coefficient of discharge Cd =
8@?9D@A
89:;=<9>?@A
9. HYDRAULIC TURBINES
• Hydraulic turbine is a prime mover in which shaft work is developed by
converting the potential or kinetic energy possessed by a liquid into
mechanical energy.
• The turbine will be directly coupled to a generator which generates electrical
energy.
• Hydraulic turbine consist of a wheel known as runner having a number of
curved vanes on its periphery.
• Based on method of energy conversion hydraulic turbines are classified into
impulse and reaction turbines.
• In impulse turbine all available potential energy of water is initially converted
to kinetic energy by means of a nozzle. The high velocity jet of water coming
out of the nozzle strikes a series of vanes fixed around the turbine wheel. This
results in an impact force on the vanes making the runner to rotate.
• In reaction turbines only a portion of available potential energy of water is
converted to kinetic energy before entering the runner. The remaining energy
remains as pressure head which while passing through the runner vanes is
subjected to conversion from pressure to kinetic energy. The increase in
kinetic energy relative to the runner results in a reaction force causing the
runner to rotate.
10. CONTINUED….
• Net head: it is the head available at the inlet of the turbine after deduction of
various types of head losses due to friction, pipe bend etc.,
• Head loss due to friction =
!"#$%
&'(
f = coefficient of friction
l = length of penstock
v = velocity of water
D = diameter of penstock
• Hydraulic efficiency ( )*) =
+,-./ 0.#1$./.0 2, /344./
5,-./ 6$61#67#. 62 14#.2 ," 23/714.
• Mechanical efficiency ()8.9* ) =
+,-./ 5/,039.0 62 :*6"2 ," 23/714.
+,-./ :355#1.0 2, /344./
• Overall efficiency (), ) =
+,-./ 6$61#67#. 62 2*. :*6"2 ," 23/714.
+,-./ :355#1.0 62 14#.2 ," 2*. 23/714.
11. PELTON WHEEL TURBINE
• Pelton turbine is a high head(200-2000m), low discharge impulse turbine.
