Hydraulic Machines MCQ with answer and solution

Concept

In a radial flow reaction turbine, water flows along the radius of the runner wheel. In an outward flow turbine, water moves from the inside center toward the outside rim.

Step-by-step solution

1. Understand the classification of radial flow turbines based on flow direction. 2. In an inward flow radial turbine, water enters at the outer periphery and flows toward the center (e.g., Old Francis turbine). 3. In an outward flow radial turbine, water enters at the center of the wheel and flows outwards toward the outer periphery (e.g., Fourneyron turbine). Answer: (B) The water enters at the centre of the wheel and then flows towards the outer periphery of the wheel.

Explanation

In an outward flow reaction turbine, the runner surrounds the guide blades. Water enters near the center (inner diameter) and travels outward towards the outer circumference. As water flows through the curved blades, its pressure energy and kinetic energy drive the runner.

Why the other options are wrong

A: Flow parallel to the axis describes an axial flow turbine (like Kaplan or Propeller). C: Entering at the outer periphery and flowing to the center describes an inward flow turbine. D: Partly radial and partly axial describes a modern mixed flow turbine.

Shortcut

Outward flow = From Inside (centre) to Outside (periphery).

Common mistake

Students often confuse inward flow with outward flow turbines.