Unsteady Rotor - Stator Analysis of Hydraulic Pump - Turbine : CFD and Experimental Approach

The parallel rotor-stator computation capabilities of Fine Turbo and CFX-TASCflow CFD commercial codes have been investigated within the frame of the European ESPRIT project HPNURSA. Unsteady computations have been performed for simple test cases, where flow conditions are known, the numerical results indicate that the unsteady rotor-stator interaction model is capable of accurately reproduce the features of the incompressible flow encountered in hydraulic turbomachines. It is also shown that R-S computations are very demanding in mesh refinement if small scales flow structures must cross the R-S interface. Finally, the behaviour of an industrial pump-turbine, by VA Tech Hydro, is investigated using CFX-TASCflow. The unsteady computation results were validated by LDV and PIV measurements, showing that unsteady R-S computations could reproduce the experimental flow features for nominal and off-design operation conditions for this pump-turbine.