Comparison of the hydrodynamic performance of front and rear-stator pump-jet propulsors in an oblique wake under the cavitation condition

Abstract

Pump-jet propulsors, which exhibit high efficiency and low noise, are widely used in underwater vehicles. In a marine environment, a nonuniform wake and an oblique flow affect a propulsor's hydrodynamic force. Therefore, the hydrodynamic performance of front and rear-stator pump-jet propulsors under complex operational conditions was compared in this study. The unsteady hydrodynamic performance was predicted using a shear stress transport k-ω model. When the calculation converged, the Schnerr-Sauer cavitation model was used to simulate the cavitation performance. After an analysis of grid independence and a verification of the calculation model's reliability, the hydrodynamic performance of two pump-jet propulsors in an oblique wake was simulated under the non-cavitation and cavitation conditions. The results indicate that under the non-cavitation condition, the performance of the front-stator pump-jet propulsor worsens more slowly with an increase in the inflow angle. Moreover, the rear-stator pump-jet propulsor stops exhibiting high efficiency when the flow angle (β) is 30°. When cavitation occurs, the performance of the two pump-jet propulsors worsens and their hydrodynamic coefficients decrease rapidly. When β = 30°, the front and rear-stator pump-jet propulsors lose 60% and 40% of their thrust, respectively. The results of this study indicate that cavitation generation has a greater impact on the performance of a front-stator pump-jet propulsor.