来流条件对轴流喷水推进器性能的影响研究

The inflow conditions of high-speed ship are significantly complicated during the process of navigation. To reveal the influence of inflow conditions on propulsion performance，this paper conducted the numerical simulation under different inflow velocities and angles of the axial water-jet propulsor. The characteristics of propulsion and internal flow characteristics under different inflow conditions are obtained based on the homogeneous flow model，Zwart cavitation model and SST k-ω turbulence model. The reliability of the numerical calculation method is verified according to the grid uncertainty analysis，comparison between numerical and experimental results and the error analysis. It is found that the flow rate increases continuously，however，the head，thrust and efficiency increase firstly and then decrease with the increasing inflow velocity. The best performance of propulsion is obtained at v=5.6m/s. The cavitation occurred on the impeller is slight when the rotational speed is 2450r/min. When the inflow velocity is not less than 8.4m/s，the flow rate increases significantly，which leads to the reduction of incidence angle. Therefore，the flow separation on pressure surface is enhanced and cavitation appears on this condition. The increase of inflow angle slightly affects the propulsion performance under lower velocity condition. However，the higher inflow velocity leads to the substantial decline of thrust，head and efficiency，which decrease by 13.8%，13.9% and 8.3%，respectively，when the inflow angle changes from 3° to 7°. The velocity inhomogeneity of each overcurrent component and the turbulence dissipation of the impeller and guide vane significantly increase with the increase of inflow angle. Moreover，the decrease of incidence angle strengthens the flow separation on pressure surface. All of those weaken the working capacity and result in a sharply deterioration of propulsion performance.