Tip leakage vortex trajectory and dynamics in a multiphase pump at off-design condition

Abstract

Because of the clearance and pressure difference between the pressure side (PS) and the suction side (SS), the tip leakage flow developed and evolved into tip leakage vortex (TLV). The relationship between the swirling strength of TLV and the pressure difference between the PS and the SS was analyzed. The velocity distribution in the tip clearance was also investigated in a multiphase pump. The reliability of numerical method was verified using high-speed photography. The trajectory of TLV was found to be distributed in a wavy shape and the swirling strength of TLV was positively correlated with the pressure difference between the PS and the SS. The tip separated vortex was formed when the tip leakage flow entered the tip clearance, and the TLV was formed when tip leakage flow moved out of the tip clearance. The low-pressure region in the tip clearance consisted of two parts. The part near the PS was caused by the tip separated vortex, and the other part near the SS was caused by the TLV. In addition, the flow separation phenomenon occurred at the radial coefficient of 0.97 and led to the increase of the turbulent energy loss of the pump.