Numerical simulation for flow characteristics of axial flow hydraulic turbine runner

The design of runner blade of turbine is done for certain flow velocities and angles but these parameters vary with operating conditions. The experimental testing of turbine model is costly, time consuming and gives performance characteristics of turbine as whole based on global parameters. The component wise performance of turbine based on local parameters is more useful for efficient design and it is very difficult to get these from model testing. The computational fluid mechanics (CFD) is an effective tool to provide detailed flow information inside turbine space and it can also give performance characteristics of turbine in terms of global as well as local parameters. The viscous 3D turbulent simulation has been carried out in an experimentally tested model of axial flow hydraulic turbine at different operating regimes and global and local parameters have been computed. The variation of computed parameters justifies with the characteristics of axial flow turbine. The computed efficiencies at some regimes of operation are critically compared with experimentally tested model results and found to bear close comparison.