Optimal Design and Experimental Study on Hydrodynamic Performance of Submerged Water Jet Propulsor

Driven by global carbon reduction and eco-environmental protection demands, submergedwater jet propulsion technology has emerged as a pivotal direction for marine power innovation, leveraging its advantages of low noise, strong operational adaptability, and high-speed efficiency. This study constructs a preliminary model of a novel submergedwater jet propulsor based on axial flow pump theory, optimizing rotor tip leading-edge angle, tip trailing-edge angle, and stator root trailing-edge angle, tip trailing-edge angle via central composite design (CCD) and response surface methodology(RSM). To evaluate its hydrodynamic performance, a high-precision computational fluid dynamics (CFD) model was built and validated through open-water tests and cavitation tunnel experiments at 4–22 m/s inflow velocities. 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. Cavitation simulations and experimental observations reveal tip-clearance vortex cavitation occurring mid-chord near the tip trailing edge develops as free vortices downstream, exerting no substantial impact on propulsion performance. These findings confirm the propulsor reliable performance under the tested complex flow conditions, providing theoretical support and practical references for green marine propulsion system design at 25–40 knots.