Differences between Francis and Kaplan Turbine

The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts.

The Kaplan turbine is a propeller-type water turbine that has adjustable blades. It combines automatically adjusted propeller blades with automatically adjusted wicket gates to achieve efficiency over a wide range of flow and water levels.

The tabular form gives a comparison between Francis and Kaplan turbines below.

S.no
Francis Turbine
Kaplan Turbine
1 Francis turbine is a mixed flow turbine. The Kaplan turbine is a purely axial flow turbine.
2 Francis turbine has a large number of blades in the runner and it varies from 16 to 24. Kaplan turbine has a small number of blades in the runner and it varies from 3 to 8.
3 The runner blades are not adjustable. The runner blades are adjustable.
4 The disposition of the shaft may be horizontal or vertical. The disposition of the shaft is always vertical.
5 Francis turbine is a medium head turbine and the head varies between 60 m to 250 m. Kaplan turbine is a low head turbine capable of working under the head less than 60 m.
6 Francis turbine works under medium discharge. Kaplan turbine works under high discharge.
7 Francis turbine specific speed varies from 50 to 255. Kaplan turbine specific speed varies from 255 to 860.
8 Resistance is significant due to many vanes and the greater area of contact with water. Resistance to overcome is less due to fewer vanes and less contact area.
9 The ordinary governor is used for his governing. The heavy-duty governor is used for its governing.
10 For the same power, it is less compact. For the same power, it is more compact.
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Vinodh Reddy is a Mechanical Engineer and Editor-in-chief of ME Mechanical. He holds a Bachelor of Engineering (Honours) degree in Mechanical Engineering. He is interested in the manufacturing field.

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