通气空泡重力效应研究

Research on the gravity effect of ventilated cavitating flows

该文基于VOF方法和有限体积法,求解气水多相流动的RANS方程及标准k-ε湍流模式,研究了通气空泡的重力效应。结果表明模拟得到的绕圆盘通气空泡的重力效应与Buyvol的分类准则吻合,通过数值模拟复演了通气空泡的双涡管泄气模式;证实由于与尾空泡的相互作用,重力作用下绕航行体通气空泡在尾部附近出现下沉,航行体上的空泡截面呈现出"月牙"形;阻力随空化数而减小,并在空泡完全包裹住航行体前部锥段时出现突降。

In this paper, based on VOF method and finite volume method, the gravity effect of ventilated cavitating flows is studied by solving the RANS equations and standard k - ε turbulence model. The numerical results show that the gravity effect on the ventilated cavitation around a disk agrees with Buyvol＇s criterion, and the phenomenon of gas evacuation by two double hollow vortices is shown through numerical simulation. It is confirmed that the ventilated cavity around a vehicle with gravity effect will move toward its tail due to the interaction with trailing cavity, and the cross section of cavity deforms along the vehicle and appears crescent shape downstream. The drag decreases with cavitation number, and reduces abruptly when the cavity completely enwraps the cone which is the fore part of vehicle.