Optimal design and experimental study on hydrodynamic performance of submerged water jet propulsor

Driven by global carbon reduction and eco-environmental protection demands, submerged water jet propulsion is a promising marine power technology featuring low noise and high efficiency. This study constructs a model of a novel submerged water jet propulsor based on axial flow pump theory. Rotor and stator blade angles are optimized using central composite design (CCD) and response surface methodology (RSM). Hydrodynamic performance is evaluated by validated CFD simulations, open-water tests and cavitation tunnel experiments. Results show the optimized propulsor achieves a 3.51% increase in open-water efficiency compared to the original design, maintaining over 65% efficiency across 25–40 knot speeds, with approximately 75% efficiency at 35 knot. Detected tip-clearance vortex cavitation has negligible impact on propulsion performance. This work provides theoretical support for the design of green high-speed marine propulsion systems.