Difference between impulse and reaction turbine


Difference between impulse and reaction turbine

The difference between impulse and reaction turbine are :-

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Impulse Turbine

1.In impulse turbine all hydraulic energy is converted into kinetic energy by a nozzle and it is is the jet so produced
which strikes the runner blades.

2.The velocity of jet which changes, the pressure throughout remaining

3.Water-tight casing IS not necess ary.Casing has no hydraulic function to perform. It only serves to prevent splashing and guide water to the tail race.

4.Water is admitted only in the form of jets. There may be one or more jets striking equal number of buckets simultaneously.

5.The turbine doesn’t run full and air has a free access to the bucket.

6.The turbine is always installed above the tail race and there is no draft tube used.

7.Flow regulation is done by means of a needle valve fitted into the nozzle.

Reaction Turbine

1.In reaction turbine only some amount of the available energy is converted into kinetic energy before the fluid enters the runner.

2.Both pressure and velocity changes as fluid passes through a runner. Pressure at inlet is much higher than at outlet.

3.The runner must be enclosed within a watertight casing.

4.Water is admitted over the entire circumference of the runner.

5.Water completely fills at the pass ages between the blades and while flowing between inlet and outlet sections does work on the blades.

6.Reaction turbine are generally
connected to the tail race through a draft tube which is a gradually expanding passage. It may be installed below or above the tail race.

7.The flow regulation in reaction turbine is carried out by means of a guide-vane assembly. Other component parts are scroll casing, stay ring runner and the
draft tube.

Difference between impulse and reaction turbine

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