Utilization of a VTR for Flow Visualization in the Rotor of a Pump Turbine

Fluid flow in the rotor of a Francis-type pump-turbine was visualized using a water-table model by means of a tracer method and was pictured using a video camera rotating with the rotor. The moving flow pattern was compared with the predicted stream lines based on a potential flow analysis as well as conventional stills. It is demonstrated that a video movie technique is useful to visualize an unsteady flow and a slow motion with a reverse flow especially in a rotating impeller.