Difference Between Impulse and Reaction Turbine [With PDF]

difference between impulse and reaction turbine

Share this Post

The main differences between Impulse and Reaction turbines are, all hydraulic energy is converted into kinetic energy by a nozzle in the Impulse turbine and whereas In Reaction turbine Only some amount of the available energy is converted into kinetic energy.

Before moving to further detailed explanation lets have some overview of Impulse and Reaction Turbine.

Note: At the bottom of every article the PDF link is attached make sure if you want you can easily download.

Impulse Turbine:

The impulse turbine changes the velocity of the water jet. The jet impinges on the turbine curved blade 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 act through a distance (work) and the diverted water flow is left with diminished energy.

Prior to hitting the turbine blades, the water pressure (potential energy) is converted to kinetic energy by a nozzle and focused on the turbine.

No pressure changes occur at the turbine blades, and the turbine doesn’t require housing for operation.

Newton’s second law describes the transfer of energy for impulse turbine.

Impulse turbines are most often used in a very high head application. This turbine works at atmospheric pressure.

The Impulse turbines are- Turgo, Jornal, Banki, Girad and Pelton Turbine.

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), there must be fully submerged in the water flow.

Newton’s third law describes the transfer of energy for the reaction turbine. Most water turbines used a reaction turbine.

They are used in a low and medium head application. This turbine works above the atmospheric pressure.

The Reaction turbines are- Thompson, Francis, Kaplan, Fourneyron and Propeller Turbine.

difference between impulse and reaction turbine
Difference between Impulse and Reaction Turbine

Difference Between Impulse and Reaction Turbine:

SL. NOIMPULSE TURBINEREACTION TURBINE
1All hydraulic energy is converted into kinetic energy by a nozzle.Only some amount of the available energy is converted into kinetic energy.
2Required less maintenance.Here it’s required more maintenance.
3The degree of reaction is zero.The degree of reaction is between ‘0’  to ‘1’
4It needs a low discharge of water.It needs medium and high discharge of water.
5Water flow is a tangential direction to the turbine wheel.Water flow is a radial and axial direction to the turbine wheel.
6Here is having more hydraulic efficiency.It’s having relatively less efficiency.
7Impulse turbine operates at high water heads.It operates at medium and low heads.

Other Points are:

8An example of an impulse turbine is the Pelton wheel.An example of a Reaction turbine is Francis, Kaplan turbine.
9Flow regulation is done by means of a needle valve fitted into the nozzle.Flow regulation is carried out by means of guide vane assembly.
10The turbine is always installed above the tailrace and there is no draft tube used.The reaction turbine is generally connected to the tailrace through a draft tube which is gradually expanding passage.
11The turbine doesn’t run full and air has free access to the bucket.Water completely fills at the passage between the blades and while flowing between the inlet and outlet sections does work on the blades.
12Water is admitted only in the forms of jets. There may be one or more jets striking an equal number of buckets simultaneously.Water is admitted over the entire circumference of the runner.

So this our short presentation on the difference Impulse turbine and Reaction turbine, I hope you like it if so, let me know your thoughts in the comment section.

FAQ:

What is Impulse Turbine?

The impulse turbine changes the velocity of the water jet. The jet impinges on the turbine curved blade which changes the direction of the flow. The resulting change in momentum (impulse) causes a force on the turbine blades.

What is the 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), there must be fully submerged in the water flow.
Newton’s third law describes the transfer of energy for the reaction turbine. Most water turbines used a reaction turbine.

What is the difference between the Impulse and Reaction Turbine?

In an Impulse turbine, All hydraulic energy is converted into kinetic energy by a nozzle whereas In a Reaction turbine Only some amount of the available energy is converted into kinetic energy.

Here are some Hand-picked articles for you:

References:

https://www.sciencedirect.com/topics/engineering/impulse-turbine