微型涡流发生器对空化初生特性的影响

Effects of the micro vortex generator on the cavitation inception characteristics

为减小空化对水下装备性能带来的不良影响,开展了空化抑制方法的研究。采用均相流模型并耦合SSTγ-Reθt湍流模型以及Zwart空化模型对带有微型涡流发生器(micro vortex generator,MVG)的水翼在不同攻角下(4°、6°、8°)的初生空化流动进行了数值模拟。研究结果表明:MVG可以明显提升水翼近壁流速且使边界层厚度有所增加;MVG对边界层分离特性的影响规律受来流攻角影响较大,当MVG位于分离点之前时(4°攻角)分离涡尺度减小,而位于分离点之后时(6°和8°攻角)分离涡尺度增大;3种攻角条件下,MVG均能够明显降低水翼的初生空化数,相比之下,8°攻角时初生空化数的降幅最大,表明MVG对空化的抑制效果受攻角的影响较大。研究成果可为工程实践中抗空化性能的设计提供一定的理论参考。

In order to reduce the adverse effects of cavitation on the performance of underwater equipment,research on cavitation suppression methods is conducted.The homogeneous flow model coupled with SSTγ-Reθt turbulence model and Zwart cavitation model is used to simulate the inception cavitation flow of a hydrofoil with a micro vortex generator(MVG)at different attack angles(4°,6°and 8°).The results show that MVG can significantly increase the near-wall velocity of the hydrofoil and increase the boundary layer thickness.The influence of MVG on the boundary layer separation characteristics of hydrofoil is related to the attack angle of hydrofoil.The separation vortex scale decreases when the MVG is located before the separation point(4°)and increases when it is located after the separation point(6°and 8°).Under the conditions of three attack angles,MVG can significantly reduce the incipient cavitation number of the hydrofoil.In contrast,the decrease of the incipient cavitation number is the largest at 8°angle of attack,indicating that the suppression effect of MVG on cavitation is influenced by the attack angle.The research results can provide some theoretical reference for the design of anti-cavitation performance in engineering practice.