Effect of the tip clearance on tip leakage vortex and pressure fluctuation characteristics in a helico-axial flow multiphase pump

Abstract

Tip clearance inevitably exists in helico-axial flow multiphase pumps, which generates a great impact on flow characteristics. To select a reasonable tip clearance and improve the transporting efficiency, different tip clearances (Rtc = 0.5, 1.0, and 1.5 mm) are chosen to investigate the flow behaviors and hydraulic characteristics. Based on the shear stress transport k-ω turbulence model, the unsteady Reynolds averaged Navier–Stokes equations are applied to solve the unsteady flow. Results show that when the tip clearance increases, the tip leakage vortex (TLV) near the tip gradually becomes obvious and the pressure fluctuation near the TLV also becomes larger. The spatial–temporal evolution is divided into three stages: split stage, contraction stage, and recurrence stage. Besides, the rotor–stator interaction is still the primary cause for the pressure fluctuation.