Theoretical Prediction of Cavitation in Radial Inflow Turbines at Design and off-Design Conditions

Abstract

A theoretical method for the prediction of cavitation in hydraulic radial turbines is developed in this work. The method combines a steady, quasi-three dimensional analyses which are based on the streamline curvature technique with an approach for the prediction of cavitation based on the definition of "available" and "required" cavitation coefficients. A radial inflow turbine is selected as a test case to investigate the capability of the present method as a cavitation prediction tool at design and offdesign conditions. The effects of various operating conditions on the cavitation inception are examined at constant values of total head and turbine suction head. It has been found that cavitation is formed near the outlet when the turbine operated at the design speed. While at off-design speeds and flow rates, cavitation covers longer distances along suction and pressure surfaces.

Keywords

• cavitaion
• hydraulic turbine
• through flow analysis
• cavitaion coefficient