海洋污损对螺旋桨叶切面性能影响的数值模拟

Numerical simulation of the effects of biofouling on the hydrodynamic performance of propeller blade sections

通常情况下,舰艇螺旋桨桨叶表面为抛光金属材质,没有涂装防污涂层,使得桨叶易受到海洋污损生物的附着和侵蚀,然而污损对螺旋桨性能的影响研究较少。采用CFD方法对污损螺旋桨叶切面流场分布进行数值模拟,在污损生物群落中选取藤壶作为污损对象,并在几何层面上进行直接建模。计算结果表明,污损使得叶切面边界层分离更早、分离区域更大,进而使得叶切面升阻比显著降低(最大降低了近90%),从而导致螺旋桨推进效率大幅降低;当藤壶高度超过一定阈值后,藤壶的继续生长对叶切面升阻力的影响变得较小。

Generally, propeller surfaces are made from polished metal and have no antifouling provision, making them vulnerable to biofouling, yet the effects of such fouling on the performance of propellers are rarely studied. The present work simulates the flow field distribution around the fouled blade section by means of CFD. Barnacles are selected as the major subject from the fouling community and are directly modeled on a geometric level. The results show that the fouling causes earlier separation of the boundary layer and increases the separation region, which further leads to significant reduction of the lift-drag ratio （up to about 90% in maximum）, and would thus result in remarkable decrease in the propulsive efficiency of propellers. However, when the height of barnacles exceeds a certain limit, their future growth yields limit- ed effects on the lift-drag ratio.