气-液两相流界面迁移现象的数值模拟研究

Numerical Simulation of the Interface Movement in Gas-Liquid Two-Phase Flows

借助于LevelSet函数,建立了气-液两相的统一控制方程组,并在交错网格中进行离散.用两种格式,即Superbee TVD格式和5阶WENO格式求解LevelSet函数的输运方程,用SIMPLER算法的思想对主流场控制方程的求解方法进行改进.数值实验结果表明,在求解LevelSet的控制方程时,5阶WENO方法比Superbee TVD格式的结果更准确;用改进的数值算法可成功实现对密度比大于1000/1的气-液两相流界面迁移问题的数值模拟.对几种典型大密度比气-液两相流问题的计算结果与实际问题的物理规律完全一致,验证了该方法的有效性和可靠性.

General governing equations are established for the whole two-phase flow field with the help of a level set function. The equations are discretized by finite difference method in a staggered Cartesian grid system. Two schemes, i.e. the Superbee-total variation dimishing (TVD) scheme and 5-order weighted essentially non-oscillatory (WENO) scheme are adopted to solve the advection equation of the Level Set function, and a SIMPLER-based method is employed to seek solutions to the momentum equations of the two-phase flow. The numerical results show that the 5-order WENO scheme is much more effective than the Superbee-TVD scheme when applied to the computation of the Level Set equation, and the presented numerical method is suitable for the solution to gas-liquid two-phase flows with a liquid-gas density ratio larger than 1000/1. Computations of several typical gas-liquid two-phase problems of large liquid-gas density ratios show that the numerical simulation can reasonably revealed the physical mechanisms and the method is quite promising in simulating the behaviors of moving interfaces in gas-liquid two-phase flows.