近自由液面螺旋桨吸气数值模拟

Numerical simulation of propeller ventilation near the free surface

基于雷诺时均(RANS)法,采用剪切应力输送(SST) k-ω模型及与流体体积(VOF)法相结合的方式,对近自由液面工作的螺旋桨进行数值模拟,分析了螺旋桨与自由液面的相互作用关系及吸气对螺旋桨的影响.结果表明:吸气的发生机制与自由液面涡和梢涡有关,且自由液面涡和梢涡的作用大小与螺旋桨的浸没深度相关;螺旋桨由于吸气现象会出现推力损失及扭矩损失,且当螺旋桨与自由液面的距离越近、进速系数越小时,推力损失和扭矩损失的变化波动越剧烈,其稳定后的平均值也越小;由于吸气现象引起的自由液面的不规则变形会对螺旋桨的性能产生较大影响.

In order to analyze the hydrodynamic performance of propeller and ventilation mechanism,based on the Reynolds average Navier-Stokes (RANS) method,the propeller operating near the free surface was simulated using the shear stress transport (SST) k -? model and the volume of fluid (VOF) method,and the interaction between propeller and free surface and the effect of ventilation on the propeller were analyzed in detail.The results show that the mechanism of ventilation is related to the free surface vortices and tip vortices,and the effect of the free surface vortices and tip vortices is related to the submergence ratios of the propeller.The propeller experiences thrust loss and torque loss due to ventilation,when the distance between the propeller and the free surface is close and the advance coefficient is small,thrust loss and torque loss fluctuate wildly,the mean values of which after stabilization also become small.The irregular deformation of free surface due to ventilation will have a great influence on the performance of propeller.