# Difference between impulse and reaction turbine [with Pdf]

The main difference between impulse and reaction turbine is that in the impulse turbine the pressure of working fluid is completely converted into kinetic energy before it hits the turbine blades while in the case of reaction turbine the pressure is gradually converted into kinetic energy in multiple numbers of stages.

The purpose of the turbine is to convert fluid energy into mechanical work. This turbine is generally classified into impulse and reaction turbines.

It is also classified on the basis of type of fluid example:- Steam and water. In this article, we have provided separate differences for hydraulic and steam turbine

Contents

## 1) Steam turbine:

In a steam turbine, the working fluid is steam. The pressure of steam is converted into the mechanical work of the shaft.

This turbine is classified as:

A) Impulse turbine:-

In an impulse turbine the total pressure energy of the fluid is completely converted into kinetic energy before it strikes rotor blades.

The impulse turbine is based on the principle of impulse. The speed of this turbine is faster hence compounding is required in this type of turbine to regulate speed.

Examples:- DA-Laval turbine.

B) Reaction turbine:-

The flow of steam glides onto the rotor blades and the reaction force generated drives the rotor blades. In a reaction turbine, the pressure gradually decreases in multiple stages. The speed of this turbine is less hence it doesn’t require compounding.

Example:- Parson’s turbine.

## 2) Hydraulic turbine:

In this type of turbine, the working fluid is water. The water at a higher head is used to rotate the shaft of the turbine.

It is generally used for power generation in power plants. It requires a large volume of water at a higher head.

The turbine is classified as,

### A) Impulse:-

In this type of turbine, the jet of water impinges on the turbine bucket to rotate the rotor. So the water enters in the tangential direction.

It requires less discharge of water at the higher head. The turbine works at atmospheric pressure. The casing is generally used for the enclosure. it doesn’t have any hydraulic function.

Eg. Pelton wheel turbine.

### B) Reaction:-

In a reaction turbine, the flow of water is guided by guide vanes which rotate the turbine. This type of turbine requires a higher flow rate of water and the casing completely filled with water while running.

The casing performs a major role in this type of turbine as it guides the flow of water. The turbine works at higher pressure.

Examples:- Francis, Kaplan.