Hydraulic turbines convert hydraulic energy from flowing water into mechanical energy. They are classified as either reaction turbines or impulse turbines. Reaction turbines experience pressure changes through both fixed and moving blades, while impulse turbines only experience velocity changes from jet impacts. Common reaction turbines are Francis and Kaplan turbines, which are used in low- and medium-head applications like dams. The Pelton wheel is an example of an impulse turbine, where individual jets strike rotating buckets to generate torque. Power developed depends on factors like efficiency, density, head, flow rate.

1. Hydraulic Turbines
A:SIVA PRATAP REEDY
16KB1A0304
II ME-A

2. Hydraulic
Introduction
Classification
Reaction Turbine
Impulse Turbine
Turbine

3. Introduction
The hydraulic machines that
convert hydraulic energy into
mechanical energy is called
Hydraulic Turbine.
Water turbines were developed
in the 19th century and were
widely used for industrial power
prior to electrical grids.
Now they are mostly used
for electric power generation.
Water turbines are mostly found
in Embankment dams to
generate electric power from
water kinetic energy.

4. Classification
Hydraulic
Turbines
Reaction
Turbine
Impulse
Turbine

5. Reaction Turbine
Reaction turbines are acted on by water, which changes
pressure as it moves through the turbine and gives up its
energy.
They must be encased to contain the water pressure (or
suction), or they must be fully submerged in the water flow.
Most water turbines in use are reaction turbines and are used
in low (<30m/98 ft) and medium (30-300m/98–984 ft) head
applications. In reaction turbine pressure drop occurs in both
fixed and moving blades. It is largely used in dam and large
power plants.
E.g. Francis Turbine, Kaplan Turbine.

6. Reaction Turbine
Figure shows a
reaction turbine

7. Reaction Turbine
.

8. Points Regarding Reaction Turbine
There is both a pressure drop and a fluid relative
speed change across the rotor.
Guide vanes act as nozzle to accelerate the flow and
turn it in the appropriate direction as the fluid enters
the rotor.
Part of the pressure drop occurs across the guide
vanes and part occurs across the rotor.

9. Impulse Turbine
Impulse turbines change the velocity of a water jet. The jet
pushes on the turbine's curved blades which changes the
direction of the flow. The resulting change in momentum
(impulse) causes a force on the turbine blades.
Since the turbine is spinning, the force acts through a distance
(work) and the diverted water flow is left with diminished
energy.
An impulse turbine is one which the pressure of the fluid
flowing over the rotor blades is constant and all the work
output is due to the change in kinetic energy of the fluid.
E.g. Pelton Wheel
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10. Impulse Turbine

11. Figure show the Pelton
Wheel

12. Points Regarding Impulse Turbine
The total head of the incoming fluid is converted into
a large velocity head at the exit of the supply nozzle.
Both the pressure drop across the bucket (blade) and
the change in relative speed of the fluid across the
bucket are negligible.
The space surrounding the rotor is not completely
filled with fluid.
The individual jets of fluid striking the buckets that
generates the torque.

13. Power Developed
P=η*ρ*g*h*Q
where,
η= Efficiency of turbine
ρ= Density of the liquid (kg/m3)
g= Acceleration due to gravity (9.81m/s2)
h= Head (m)
Q= Flow rate (m3/s)

14. THE END
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