Research on pressure fluctuation induced by tip leakage vortex of axial flow circulating pump under unpowered driven conditions

Axial flow circulating pumps (AFCPs) are large marine steam turbine units for large-sized ships. One peculiar operation condition AFCPs is when a ship cruises beyond certain speed, the energy of pump inflow can completely overcome frictional resisting moment itself, thereby driving impeller to rotate. Such also known as unpowered driven (UDC). At this time, fluid in artesian state. In paper, pressure fluctuation and inner AFCP under UDCs different conditions analyzed using delayed detached-eddy simulation turbulence model. It found that intensity tip leakage vortex (TLV) decreases from leading edge trailing blade, amplitude pulsation caused by TLV decreases. Due jet wake structure at blade edge, increases 7.8% optimal UDC. addition, compression–expansion term determines strength core TLV, thus affecting fluctuation. The viscous dissipation effect cause high-frequency components