喷水推进器进口流道水动力性能分析

目的]研究喷水推进器进口流道主参数对其性能的影响,为喷水推进器设计提供依据。方法]基于STAR-CCM+商业软件,通过定常雷诺平均NS方程(RANS),数值模拟分析不同进速比(IVR)工况下喷水推进器进口流道轴线高度和进流角度对其水动力性能的影响,并根据国际拖曳水池会议(ITTC)的不确定度分析规程进行数值不确定度分析。采用六面体结构化网格对计算域进行离散,采用Realizable k-ε两层湍流模型对控制方程进行封闭,离散格式为二阶。压力-速度耦合计算选用压力耦合方程组的半隐式算法(SIMPLE)。结果]结果显示,数值的不确定度小于4%,表明所采用的网格收敛性良好,数值结果可靠。结论]研究表明,当IVR=0.7~1.1时,进口流道效率较高;对于IVR较大的工况,应减小进流角;对于IVR较小的工况,则应适当增加轴线高度,以改善出口流动的不均匀度。

Hydrodynamic performance analysis of waterjet propulsor inlet duct

Objectives]The effects of the key parameters of the inlet duct of a waterjet propulsor on its hydrodynamic performance are studied,providing references for the design of waterjet propulsors.Methods]Based on STAR-CCM+software,the influence of the axis height and inlet angle of a waterjet inlet duct on its hydrodynamic performance under different intake velocity ratio(IVR)conditions is studied using steady Reynolds-averaged Navier-Stokes equations(RANS)numerical simulation.Numerical uncertainty analysis is carried out according to the international towing tank conference(ITTC)uncertainty analysis procedure.In this paper,the computational domain is discretized with hexahedral structured grids.The set of governing equations is closed using the Realizable k-εtwo-layer turbulence model,and the discretization schemes are second-order accurate.The semi-implicit method for pressure linked equations(SIMPLE)algorithm is applied in the pressure-velocity coupling calculation.Results]The results show that the numerical uncertainty is less than 4%,indicating that the grids used in this paper yield well-converged and reliable numerical results.Conclusions]The efficiency of the inlet duct is higher in the range of IVR=0.7~1.1.For large IVR,the inlet angle should be reduced.For small IVR,the axis height can be appropriately increased to improve the homogeneity of flow at the exit of the inlet duct.