Transient analysis of the pre-whirl pump-jet propulsor with different blade numbers

In this work, the verified mesh is employed to study the effect of the stator number (N_s) and rotor number (N _r) on the pump-jet propulsor performance. Based on the RNG k–ϵ turbulence model, results show that the increase of N_s has an accelerating effect on flow velocity and improves the thrust and torque. The unsteady thrust characteristics are closely related to the combination of N_s and Nr. As N_s increase, the tip vortex intensity decreases and causes a reduction in pressure fluctuation on the rotor tip regime. While for the results of different N_r with constant area ratio, the steady performance almost unchanged. And the tip vortex moves upstream as N_r increases, this results in a stronger fluctuation on the rotor pressure side. Further study of cavitating flow indicates that the increase of N_r lead to an improve of the relative cavitation range, but the cavity volume decreases.