Optimized design and energy-saving analysis of pre- shrouded vanes in propeller propulsion

This study is based on the core hypothesis that PSV can improve propulsion efficiency by enhancing the uniformity of propeller inflow and recovering wake energy.' A simulation-based design optimization (SBDO) framework was developed, integrating CAD parametric modeling, CFD numerical simulation, Design of Experiments (DOE), and surrogate modeling, to systematically perform the collaborative optimization of key geometric parameters such as duct radius, stator blade span, and angle of attack. Through dual verification with high-precision CFD simulations and large-scale towing tank experiments, the results show that the optimized PSV can achieve a 5.42% energy saving rate and a 5.13% increase in propulsion efficiency at the design speed. In-depth flow field analysis indicates that the device accelerates axial flow through the duct and applies negative pre-swirl via the stator blades, significantly reducing wake tangential velocity and vortex strength, thereby revealing the physical essence of its energy-saving capability. Parametric studies further identify that the stator blade span and angle of attack are the dominant design variables affecting energy-saving performance. This study not only provides a trial-validated, efficient optimization design process but also offers direct theoretical basis and design guidance for the engineering development of ship energy-saving devices through the revealed flow mechanisms and parameter sensitivity conclusions.