考虑挡板对空化脱落的抑制效应数值分析

Numerical simulation of inhibition effect of placed obstacles on cavitation shedding

激波和回射流是空化脱落的两种主要机制,在相同攻角下,空化数越大,回射流对空化脱落的效果就越明显。为了研究长度不同、布置方式不同的挡板对空化回射流和空化脱落的抑制效应,分别在平板和水翼的吸力面添加挡板,用来阻挡逆流而上的回射流,从而观察空化脱落的情况。数值模拟采用一种新修正的稳定化SST k-ω湍流模型,空化模型则选取了比较常用的Schnerr-Sauer空化模型。研究结果表明:在水翼吸力面布置恰当的挡板可以以较小的阻力代价换取巨额的升力提升,从而提高升阻比,提高水翼的效率,同时挡板的存在可以有效地减小片空泡的脱落和云空化的产生。

The re-entrant jet and bubbly flow shock wave phenomena are discovered to account for the shedding of the cloud cavitation.In order to study the inhibition effects of placed obstacles and control mechanism of the re-entrant jet on the generation of the cloud cavitation,numerical simulations are performed on flat hydrofoils and elliptic nose hydrofoils equipped with and without obstacles.A new modified stabilized SST k-ωturbulence model and the Schnerr-Sauer cavitation model have been used to analyze the hydrodynamic performance of the cavity flows.Research suggests that the placement of a small obstacle can inhibit the region of cavitation and restrain the shedding of sheet cavitation.Moreover,the existence of an obstacle can change the pressure distribution along the hydrofoil and more foil lift can be achieved at a relatively small drag cost.