Understanding Inward Flow Turbine Water Path

An inward flow reaction turbine is defined by how water moves through its runner. The key characteristic is the direction from the outside towards the inside.

• Inward Flow Path: In this turbine type, water is directed to enter the runner at its outer circumference.
• Radial Movement: Subsequently, the water flows radially inwards, moving from the outer periphery towards the central axis of the runner.
• Energy Conversion: This inward flow causes a pressure drop as the water moves towards the center, facilitating the conversion of hydraulic energy into mechanical work.

Therefore, the correct description is: "The water enters the wheel at the outer periphery, and then flows towards the centre of the wheel". This aligns with Option 3.

Distinguishing Other Flow Types

Understanding the flow pattern helps differentiate turbine types:

• Option 1 describes an axial flow turbine (e.g., Kaplan turbine), where water flows parallel to the turbine's axis.
• Option 2 describes an outward radial flow turbine, where water moves from the center towards the outer edge, the reverse of an inward flow turbine.
• Option 4 describes a mixed flow turbine (often seen in Francis turbines), where flow has both radial and axial components. While Francis turbines are reaction turbines, the specific definition of *inward flow* focuses on the radial inward path described in Option 3.