Clearance flow patterns and pressure distribution of a pump-turbine: Measurement and simulation of a rotating disk flow

The clearance flow patterns and pressure distribution determine the axial hydraulic thrust of a pump turbine, which has substantial impact on unit imbalance. However, due to tiny size complex shape channel, there is no detailed description characteristics. In this study, we conducted model test with particle image velocimetry (PIV) measurements CFD simulation rotating disk that was simplified pump-turbine flow. It shown typical Batchelor formed in region, demonstrating “core region + double-boundary layers” for circumferential velocity along height direction; core rotates at speed only around 41–42% independent inlet height. Driven by centrifugal force, radially outward disk, while inward stationary meridian section, showing secondary vortices. circumferentially symmetric quadratic distribution. Based liquid differential equilibrium equation velocity, can be expressed as function square runner speed. These findings used investigate force imbalance issues unit.