Classification of turbines

1. HHM
CLASSIFICATION OF TURBINES

2. Classification of Turbines
• Turbines are classified based on
 Action of water flowing through the turbine runners
 Direction of flow of water in the runner
 Head and quantity of water required
 According to their specific speed

3. 1.Based on water flowing through the turbine
• There are two types of turbines based on water flowing through turbines
 Impluse turbine : Eg:- Pelton wheel
Turgo-impulse wheel
Girard turbine etc…
 Reaction turbine : Eg:-Fourneyron turbine
Thomson turbine
Francis turbine etc…

5. 2. Based on direction of flow
• There are four types of turbines
 Tangential turbine
 Radial turbine
 Axial flow turbine
 Mixed flow turbine

6. Tangential flow turbine
In which the water flows along the tangent to the path of rotation of the
runner
Pelton wheel is the tangential flow

8. Radial flow turbine
 In which the water flows along the radial direction and remains wholly and
mainly in the plane normal to the axis of rotation, as it passes through
runner.
 There are two types of radial flow
1. Inward radial flow
2. Outward radial flow
 Fourneyron turbine, Thomson turbine are examples of radial flow.

10. Axial flow turbine
In which the water through the runner is wholly and mainly along the
direction parallel to the axis of rotation of the runner.
Propeller turbine, Kaplan turbine, Jonval turbine etc.. are the examples of the
axial flow turbine.

12. Mixed flow turbine
In which water enters the runner at the outer periphery in the radial direction
and leaves it at the centre in the direction parallel to the axis of rotation of
the runner
Modern Francis turbine is an example of the mixed flow type turbine

14. 3.Based on head and quantity of water required
• There are three types
High head turbine
Medium head turbine
Low head turbine

15. High head turbine
High head turbines are those which are capable of working under very high
heads ranging from several hundred metres to few thousand metres.
These turbines thus require relatively less quantity of water
In general impulse turbines are high head turbines
In particular Pelton wheel has so far been used under a highest head of
about 1770mts.(5800ft.)

16. Medium head turbines
 Medium head turbines are those which are capable of working under
medium heads ranging from about 60m to 250m.
 These turbines require relatively large quantity of water.
Modern Francis turbines may be classified as medium head turbines.

17. Low head turbines
 Low head turbines are those which are capable of working under the heads
less than 60m.
These turbines thus require a large quantity of water
Kaplan and other Propeller turbines may be classified as low head turbines

18. 4. According to their specific speed
• The specific speed of the turbine is the speed of a geometrically similar
turbine that would develop 1kilowatt power when working under a head of
one metre.
I. Specific speed varying from 8.5 to 30 (10 to 35) – Pelton wheel
II. Specific speed varying from 50 to 340 (60 to 400) – Francis turbine
III. Specific speed varying from 255 to 860 (300 to 1000) – Kaplan turbine