Research on hydrodynamic performance and flow characteristics of a multi-stage pump-jet propulsor

Pump-jet propulsor is widely used in underwater vehicles. Recently, multi-stage pump-jet configurations have garnered significant attention due to their superior thrust and vibration performance. This study investigates the Stator-Rotor-Stator Pump-Jet Propulsor (SRS-PJP), focusing on five key parameters and the contribution of two stator stages. The first phase focuses on the influence of five important parameters: the length of pre-stator (L-ps), the length of rotor (L-r), the length of rear-stator (L-s), the gap from rotor to pre-stator (G-r2ps) and the gap from rotor to rear-stator (G-r2s). Results indicate that L-ps and L-r exert the most pronounced effects on performance, followed by L-s and G-r2ps, while the influence of G-r2s is relatively minor. This understanding allows for optimization of design parameters, leading to gains in both efficiency and thrust. Subsequently, the contribution of stator stages on the performance is investigated. A comparative analysis is conducted among the prototype propulsor alongside two modified variants, in which the pre-stator or rear-stator are removed, respectively. The results demonstrate that the SRS-PJP combines the benefits of both front and rear stators, delivering advantages in both steady and unsteady hydrodynamic performance. This work elucidates the parametric effects and stator-stage synergy in SRS-PJP, offering practical fundamentals for designing efficient, high-thrust multi-stage propulsors.