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: ny o var ous mac nes n w c e

energy of a moving fluid is

impulse or reaction of the fluid with a

, ,

arrayed about the circumference of a

wheel or c linder.

energy

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Two types of water turbine:

Impulse turbine and Reaction turbine

Impulse turbine : a turbine that is driven by jets

directed a ainst the blades

to develop torque from gradual

to exhaust

Can be classified by low head, medium head and

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Types of impulse turbine :

,medium head : Crossflow, Turgo, Multi-jet Pelton

medium head : Francis

ow ea : rope er, ap an

e on rope er

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eac on ur ne

acted on by water, which changes pressure

blades

fixed blades shaped and mounted to providenozzle-shaped spaces between the blades

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Reaction turbine is moved by 2 main forces

1. the reactive force produced on the moving

blades when the fluid changes direction

2. the push or impulse of the fluid impinging uponthe blades

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mpu se ur ne changes velocity of the water jet

et im in es on the turbine which reverses the

flow resulting in change in momentum.

water pressure is converted to kinetic

.

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Power

e power ava a e n a s ream o wa er s;

Where:

= turbine efficiency

= 3

g = acceleration of gravity (9.81 m/s2)

h = head m . For still water this is the difference inheight between the inlet and outlet water surface.

Moving water has an additional component added to.head equals the pressure head plus velocity head.

= flow rate m3/s

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Francis turbineTheory of Operation

Casement is needed to contain the water flow.The turbine is located between the high

water exit

runner causing the runner to spin

spinning radius decreases

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High flow low flow

Francis turbine with generator

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Pelton consists of a wheel with a series

of split buckets set around its rim

a high velocity jet of water is directed

The jet hits each bucket and is

s lit in half so that each half is

turned and deflected back almostthrough 180

Nearly all the energy of the water

goes into propelling the bucket

a discharge channel below.

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Tur o

the jet is designed to strikethe lane of the runner at anangle (typically 20) so that

the water enters the runner on .

Therefore the flow rate is notlimited by the discharged fluid

n er er ng w e ncom ng e(as is the case with Peltonturbines .

As a consequence, a Turgo

turbine can have a smallerame er runner an a e onfor an equivalent power.

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Crossflow a drum-like rotor with a solid

disk at each end and gutter-

two disks

A et of water enters the toof the rotor through thecurved blades, emerging on

passing through the blades a2nd time

shape of the blades is suchthat on each passage

rotor the water transferssome of its momentum,

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focus on economical performance,

environmental efficiency, reliability,easy- o-serv ce es gns, an ong serv ce e

turbine blade is designed to optimize the energycapture

use power electronics to allow for variable rotorspeed operation to improve efficiency, control

structural loads and improve power quality