2.1.2 Water Turbines

TURBINE
Turbines are the hydraulic machines

which convert hydraulic energy
into mechanical energy.
HYDRAULIC TURBINES MECHANICAL

ENERGY ENERGY
CLASSIFICATION OF TURBINES
 According to the type of energy at inlet:

 Impulse turbine :
 (P.E. of water converted to K.E. before striking to runner )
 Reaction turbine:
 According to the direction of flow through runner:
 Tangential flow turbine

 Radial flow turbine
 Axial flow turbine
 Mixed flow turbine.
 According to the head at the inlet of turbine:
 High head turbine

 Medium head turbine
 Low head turbine.
 According to the specific speed of the turbine:
 Low specific speed turbine

 Medium specific speed turbine
 High specific speed turbine.
If at the inlet of turbine the energy available is only kinetic
energy, the turbine is known as Impulse Turbine.
 If at the inlet of turbine water possesses kinetic energy as

well as
pressure energy,the turbine is known as Reaction Turbine.
 If the water flows in radial direction through the runner the
turbine is known as Radial flow turbine.
 If water flows along the tangent of runner the turbine is known
as
Tangential flow turbine.
 If the water flows from outward to inward radially the turbine is

known as Inward radial flow turbine.
 If the water flows from inward to outward radially the turbine is

known as Outward radial flow turbine.
 If water flows along the direction parallel to the axis of rotation of

runner, the turbine is known as Axial flow turbine.
 If water flows in radial direction but leaves in the direction

parallel to the axis of rotation the turbine is known as Mixed
flow turbine.
Peltonturbine is a
tangential flow
impulse turbine.
Pelton turbine is
suitable for high
head and low flow
rate.
Energy available at
the inlet of the
turbine is only
kinetic energy.
PELTON
TURBINE
MAIN PARTS OF PELTON
TURBINE:
1.Nozzle and flow

regulating
arrangment.
2. Runner and
buckets
3. Casing
4. Breaking jet.
https://www.youtube.com/watch?v=rf9meqw2SQA
RADIAL FLOW REACTION
TURBINES
 In radial flow reaction turbines water flows in the radial
direction.
 The water may flow radially from outward to inward or from

inward to outward.
RADIAL FLOW
REACTION TURBINES.
OUTWARD
INWARD RADIAL
RADIAL FLOW
FLOW
TURBINE
TURBINE
If the water flows
from outward to
inward the turbine
is known as Inward
radial flow turbine.

from inward to
outward the turbine
is known as
Outward radial flow
turbine.
Main parts of Radial

flow Reaction Turbine:
1. Casing
2. Guide mechanism
3. Runner
4. Draft tube
Ifthe water flows
from outward to
inward the turbine
is known as Inward
radial flow turbine.
Guide wheel consists

of guide vanes which
directs the water to
enter the runner.
The outer diameter

of the runner is inlet
& inner diameter is
outlet.
INWARD RADIAL
FLOW TURBINE
from inward to
outward the turbine
is known as
Outward radial flow
turbine.
The inner diameter

of the runner is
inlet & outer
diameter is outlet.
OUTWARD RADIAL FLOW

TURBINE
https://www.youtube.com/watch?v=3BCiFeykRzo
Francis turbine
1. Spiral Casing :The blades of the turbines are circularly placed, which mean the water
striking the turbines blades should flow in the circular axis for efficient striking. So the
spiral casing is used, but due to circular movement of the water, it looses its pressure.
To maintain the same pressure the diameter of the casing is gradually reduced, so as to
maintain the pressure uniform, thus uniform momentum or velocity striking the runner
blades.
2. Stay Vanes
Stay vanes and guide vanes guides the water to the runner blades. Stay vanes remain
stationary at their position and reduces the swirling of water due to radial flow, as it
enters the runner blades. Thus making turbine more efficient.
3. Guide Vanes
Guide vanes are not stationary, they change their angle as per the requirement to control
the angle of striking of water to turbine blades to increase the efficiency. They also
regulate the flow rate of water into the runner blades thus controlling the power output
of a turbine according to the load on the turbine.
https://www.youtube.com/watch?v=3BCiFeykRzo
4. Runner Blades
The performance and efficiency of the turbine is dependent on the design of the
runner blades. In a Francis turbine, runner blades are divided into 2 parts. The
lower half is made in the shape of small bucket so that it uses the impulse action
of water to rotate the turbine. The upper part of the blades use the reaction force
of water flowing through it. These two forces together makes the runner to
rotate.
The upper part of the blades use the reaction force of water flowing through it.
Thus runner blades make use of both pressure energy and kinetic energy of water
and rotates the runner in most efficient way.
5. Draft Tube
The water coming out of runner blades would lack both the kinetic energy and
pressure energy, so we use the draft tube to recover the pressure as it advances
towards tail race.
The pressure at the exit of the runner of Reaction Turbine is generally less than
atmospheric pressure. The water at exit cannot be directly discharged to the tail race.
A tube or pipe of gradually increasing area is used for discharging water from the exit
of turbine to the tail race. This tube of increasing area is called Draft Tube.
The inward flow
FRANCIS TURBINE
reaction turbine
having radial
discharge at outlet is
known as Francis
Turbine.
In modern Francis

turbine water enters
the runner in radial
direction at outlet &
leaves in axial
direction at inlet of
runner.
Francis turbine is
suitable for
medium head and
medium flow
AXIAL FLOW REACTION
TURBINE
 If the water flows parallel to the axis of the rotation of the
shaft
the
turbine is known as Axial flow turbine.
 The axial flow reaction turbine the shaft is vertical.
 Lower end of shaft is made larger

AXIAL FLOWand known as hub/boss.
REACTION TURBINE
PROPELLER
KAPLAN TURBINE
TURBINE
When the vanes
are fixed to the
hub & are not
adjustable the
turbine is known
as Propeller
Turbine.
Ifthe vanes are
adjustable the
turbine is known as
Kaplan Turbine
https://mechanicalenotes.com/kaplan-turbine/
KAPLAN TURBINE
RUNNER.
Kaplan Turbine is
suitable for low head
and high flow rate.
Main parts of Kaplan

Turbine are:
1. Scroll casing
2. Guide vanes
mechanism
3. Hub with vanes
4. Draft tube.

2.1.2 Water Turbines

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TURBINE

Turbines are the hydraulic machines

HYDRAULIC TURBINES MECHANICAL

 According to the type of energy at inlet:

 According to the direction of flow through runner:

 Tangential flow turbine

 High head turbine

 According to the specific speed of the turbine:

 Low specific speed turbine

 If at the inlet of turbine water possesses kinetic energy as

 If the water flows from outward to inward radially the turbine is

 If the water flows from inward to outward radially the turbine is

 If water flows along the direction parallel to the axis of rotation of

 If water flows in radial direction but leaves in the direction

1.Nozzle and flow

 The water may flow radially from outward to inward or from

If the water flows

Main parts of Radial

Guide wheel consists

The outer diameter

The inner diameter

OUTWARD RADIAL FLOW

In modern Francis

 The axial flow reaction turbine the shaft is vertical.

 Lower end of shaft is made larger

Main parts of Kaplan

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