Dynamics and wear analysis of hydraulic turbines in solid-liquid two-phase flow

Abstract

To solve unstable operating and serious wearing of a hydraulic turbine in its overflow parts under solid-liquid two-phase flow, a particle model software and an inhomogeneous model in CFX are used to simulate the hydraulic turbine to understand the wearing of overflow parts and the external characteristics under the solid-liquid two-phase flow. Eleven different conditions at different densities and concentration have been calculated. The simulation results show that the volume distribution of solid particles is larger at the turn of the volute and nose end, resulting in the serious wear in this area. Due to uniform flow at the butterfly edge of volute under solid-liquid two-phase flow, the wear at the entrance of guide vane, the inlet of the blade and the outlet in the shroud is more serious than in other sections. Meanwhile, the collision between the solid phase particles and the overflow components is more intense under solid-liquid two-phase flow in the rotor which can lead to cavitation especially in the outlet and shroud of the blade. In addition, with the increase of density and concentration of solid particles the inlet and outlet pressure difference gradually rises, causing the efficiency loss of the hydraulic turbine.