基于界面跟踪方法的汽蚀模型和算法的有效性验证

NUMERICAL VALIDATION OF THE CAVITATION MODDEL AND ALGORITHM BASED ON THE LIQUID/VAPOR INTERFACE TRACKING METHOD

针对两相附着汽蚀流动机理,基于界面跟踪方法发展了新的汽蚀模型和算法。所发展的汽蚀模型和算法不仅考虑了液相／气相界面处的压力差,而且考虑了耦合Reynolds-Averaged Navier-Stokes方程求解技术得到的流场压力梯度信息来迭代计算附着汽蚀形状。采用具有试验数据的半球形头部圆柱体汽蚀绕流作为算例来验证所提出的汽蚀模型和算法的有效性。采用不同的网格数和松弛因子数值验证了发展的汽蚀模型和算法的有效性。三种汽蚀数下的数值计算结果得到的压力系数分布与试验数据完全吻合。结果表明所提出的汽蚀模型和算法能够准确模拟出汽蚀发生点和汽蚀长度。

An improved cavitation model and algorithm based on the liquid/vapor interface tracking method is presented according to the mechanism of the two-phase attached cavitation flow. The presented cavitation model is coupled with the Reynolds-Averaged Navier-Stokes solutions. The pressure distribution at the liquid/vapor interface, as well as its pressure gradient information, is taken into account in updating the cavity shape iteratively. The attached cavitation flow across a hemisphere headform/cylinder body is simulated using different grid numbers and relaxation factors to validate the feasibility of the presented model. The obtained pressure coefficient distribution is well agreed with the experimental data at three different cavitation numbers. The numerical results indicate that the presented cavitation model and algorithm can predict the inception point and length of the attached cavity shape accurately.