Correct Answer - Option 4 : Inward flow radial turbine
Explanation:
Impulse Turbine: If at the inlet of the turbine, the energy available is only kinetic energy, the turbine is known as impulse turbine. e.g. a Pelton wheel turbine.
Reaction Turbine: If at the inlet of the turbine, the water possesses kinetic energy as well as pressure energy, the turbine is known as a reaction turbine. e.g. e Francis and Kaplan turbine.
Tangential flow turbines: In this type of turbine, the water strikes the runner in the direction of the tangent to the wheel. Example: Pelton wheel turbine
Radial flow turbines: In this type of turbine, the water strikes in the radial direction. accordingly, it is further classified as
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Inward flow turbine: The flow is inward from periphery to the centre (centripetal type); Example: old Francis turbine
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Outward flow turbine: The flow is outward from the centre to periphery (centrifugal type); Example: Fourneyron turbine
Axial flow turbine: The flow of water is in the direction parallel to the axis of the shaft. Example: Kaplan turbine and propeller turbine
∴ Francis turbine is a radial inward flowing reaction turbine.
