## Introduction To Hydraulic Turbine and Classification Of hydraulic turbine

### HYDRAULIC TURBINES —DEFINITION

The hydraulic turbine is a prime mover that uses the energy of flowing water and converts  is  into  the  mechanical  energy  in  the  form  of  rotation  of  the  runner.  (A prime mover is a machine which uses the raw energy of a substance and converts it into the mechanical energy.) Since the fluid medium is water, these turbines are also known   as   the   ‘ water   turbines’ .   Hydraulic   turbines   coupled   with   hydro    — generators form the so  —called ‘ hydrounits’ which are widely used now a days for generating electrical power.

Introduction to Hydraulic (Water) Turbine -Working Of Impulse and Reaction Turbine

Classification of Hydraulic turbines:

#### 1) Based on type of energy at inlet to the turbine:

• Impulse Turbine : The energy is in the form of kinetic form. e.g: Pelton wheel, Turbo wheel.
• Reaction Turbine : The energy is in both Kinetic and Pressure form. e.g: Tubular, Bulb, Propellar, Francis turbine.

#### 2) Based on direction of flow of water through the runner:

• Tangential flow: water flows in a direction tangential to path of rotational, i.e. Perpendicular to both axial and radial directions.
• Radial outward flow e.g : Forneyron turbine.
• Axial flow : Water flows parallel to the axis of the turbine. e.g: Girard, Jonval, Kalpan turbine.
• Mixed flow : Water enters radially at outer periphery and leaves axially. e.g : Modern Francis turbine.

#### 3) Based on the head under which turbine works:

• High head, impulse turbine. e.g : Pelton turbine.
• Medium head,reaction turbine. e.g : Francis turbine.
• Low head, reaction turbine. e.g : Kaplan turbine, propeller turbine.

#### 4) Based on the specific speed of the turbine:

• Low specific speed, impulse turbine. e.g : Pelton wheel.
• Medium specific speed, reaction turbine. e.g : Francis wheel.
• High specific speed, reaction turbine. e.g : Kaplan and Propeller turbine.

#### 5) Based on the name of the originator:

• Impulse turbine – Pelton wheel, Girard, Banki turbine.
• Reaction turbine – Forneyron, Jonval, Francis, Dubs, Deriaze, Thomson kalpan, Barker, Moody, Nagler, Bell.