Analysis of the phenomenon of inlet reverse flows in a pump-turbine using 3-D numerical techniques

The purpose of this paper is to apply a developed three-dimensional CFD technology to predict the phenomenon of reverse flows created at the inlet during the pump operation of Francis type pump-turbines. The motions of the separation flows are predicted well by using a k-two equation turbulent models and a Reynolds stress model (RSM). The computational results such as the prediction of major flow patterns of the vortex on the sections of blade-to-blade, reverse flow region near the shroud surface, as well as pressure distributions on the blade surfaces are analyzed in this paper. In order to confirm the computational results, the flow measurements are carried out at the pump inlet under several flow rates.