FLUID MECHANICS AND HYDRAULIC
MACHINES
Pressure Measurement
Hydrostatic Law
Vacuum pressure is defined as the pressure below the atmospheric pressure
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HYDRAULIC MACHINES:TURBINES
INTRODUCTION:
❑ Those machines which convert either hydraulic energy into
mechanical energy or vice versa.
❑ The hydraulic machines, which convert the hydraulic energy into
mechanical energy, are called turbines, while The hydraulic
machines, which convert the mechanical energy into hydraulic
energy are called pumps.
TURBINES:
❑ The hydraulic machines, which convert the hydraulic energy into
mechanical energy. The mechanical energy is used in running an
electric generator which is directly coupled to the shaft of the
turbine.
❑ Thus the mechanical energy is converted into electrical energy.
The electric power which is obtained from the hydraulic energy is
called hydroelectric power.
LAYOUT OF HYDROELECTRIC POWER PLANT
Figure 1
A dam constructed across a river to store water.
Pipes of large diameters called penstocks, which carry
water under pressure from the storage reservoir to the
turbines. These pipes are made of steel or renforced
concrete.
Turbines having different types of vanes fitted to the
wheels.
Tails race, which is a channel which carries water away
from the turbines after the water has worked on the
turbines. The surface of water in the tail race channel is
also known as tail race.
CLASSIFICATION OF HYDRAULIC TURBINES
❖ According to the type of energy at inlet:
(a) Impulse turbine and (b) Reaction turbine
❖ According to the direction of flow through runner:
(a) Tangential flow turbine (b) Radial flow turbine
(c) Axial flow turbine (d) Mixed flow turbine
❖ According to the head at the inlet of turbine:
(a) High head turbine (500-1500m) (b) Medium head turbine
(60-250m) (c) Low head turbine (2-60m)
❖ According to the specific speed of the turbine:
(a) Low specific speed turbine (b) Medium specific speed turbine
(c) High specific speed turbine
❖ According to name of the originator:
(a) Pelton turbine-impulse turbine (high head and low discharge)
(b) Francis turbine-reaction turbine (medium head and medium
discharge)
(c) Kaplan turbine-reaction turbine (low head and high discharge)
WORKING PRINCIPLE OF PETLON TURBINE
31
IMPULSE TURBINE
32
IMPULSE TURBINE
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PUMP
❑ A pump is a hydraulic machine which converts the mechanical
energy supplied to it into hydraulic energy.
❑ On the basis of operating principle pumps can be classified as:
Rotodynamic and Positive Displacement.
Fluid is moved by dynamic action of Changes of the volume
imparting momentum to the fluid occupied by the fluid
❑ Depending on the direction of flow of liquid within the passage of
the impeller (rotating member of rotodymamic pump),
rotodynamic pump can be classified as:
Centrifugal pump, mixed flow pump and axial flow pump
Fluid is moved by centrifugal
action of the fluid
COMPONENTS OF A CENTRIFUGAL PUMP
❖ Impeller
❖ Casing:
▪Volute casing and
▪Casing with stationary guide vanes
❖ Suction pipe with a foot-valve and a
strainer
❖ 4. Delivery pipe.
Casing with stationary guide vanes
