自然通气状态下半浸桨水动力特性数值分析

Numerical Analysis of Hydrodynamic Characteristics of Surface Piercing Propeller Under Naturally Ventilated Condition

为了研究自然通气状态下半浸桨的水动力特性,以雷诺时均(RANS)方程求解流场,同时结合流体体积(VOF)方法和滑移网格技术对标准半浸桨模型841B非定常气液两相混合流场进行数值模拟.数值分析结果表明,推力系数KT和转矩系数10 KQ的计算结果与试验值吻合良好,尤其在设计点附近,两者误差均在5%以内.在尾流场中,空气腔呈螺旋状向下游发展,螺旋的直径先增大再减小,最后螺旋状的空气腔逐渐消失.由于浸深较小,半浸桨在水平方向、垂直方向上均受到很大的力和力矩.半浸桨的尾流场以自由液面为界,速度发生突变.桨盘面之前,半浸桨通过抽吸作用影响流场;桨盘面之后,滑流作用主导流场.

To study the hydrodynamic characteristics of surface piercing propeller under natural ventilation condition,the numerical simulation on the unsteady gas-liquid two-phase flow field of the standard model841 Bwas performed by solving RANS equation and combining it with the VOF method and using sliding mesh technique.The results show that the calculated values of thrust coefficient KTand torque coefficient10 KQare in good agreement with the experimental data;especially near the design point,the errors of both are within 5%.The air cavity develops downstream in spirals in the wake field;the diameter of the spiral first increases and then decreases;finally,the spiral cavity gradually disappears.The forces/moments acting on the surface piercing propeller under small immersion condition are very large in horizontal and vertical directions.The wake flow field of surface piercing propeller is bounded by the free surface.The velocity in the wake field mutates in the free surface.In front of the disk,surface piercing propeller affects the flow field by suction effect;whereas the slipstream effect dominates the flow field behind the disk.