限制水域下喷水推进器水动力特性研究

Analysis of waterjet hydrodynamic performance in restricted water

本研究采用数值模拟方法对无限水域和限制水域中喷水推进装置的水动力特性进行对比分析,开展不同水深条件下喷水推进器进流特性、进口流道效率和推进泵水力特性研究,并据此评估开式循环水槽环境下水槽侧壁和底面限制对喷水推进装置水动力性能的影响。数值计算结果表明:限制水域下喷水推进船底部和水槽底面间水流因阻塞效应使速度增加产生回流,水槽侧壁对自由液面兴波产生反射,随着水深减小,流道进口获流区平均轴向速度明显增加;不同水深吃水比下,进水流道出口非均匀度增加,但进口流道效率变化不大;相比于无限水域条件,限制水域中推进泵流量系数、扬程系数和泵效率的预报结果偏高1%~2%。

The hydrodynamic performance analysis of waterjet was numerically performed in open and re⁃stricted water conditions.The inflow characteristics of the waterjet,channel efficiency and the hydraulic per⁃formance of waterjet thrusters were analyzed under different depth conditions.The effect of the side and bot⁃tom walls of the circulating tunnel with free-surface on the waterjet performance was evaluated accordingly.The numerical results indicate that the flow between the ship hull and the bottom is accelerated due to the blocking effect in shallow water and the wave development is altered because of the side reflection.The in⁃duced reverse flow accelerates the axial velocity profiles in the capture area of waterjet inlet duct,and be⁃comes even stronger with the decrease of the water depth.The non-uniformity of the channel exit increases with the decrease of the depth-draft ratio,while the channel efficiency remains unchanged.The flow rate co⁃efficient,head coefficient and pump efficiency of the waterjet pump are slightly overpredicted in restricted water than that in open-water condition.