一种模拟大密度比多相流的混合算法

A Hybrid Method for Multiphase Flows with Large Density Ratio

  • 摘要: 在扩散界面法(diffuse interface method,DIM)的基础上提出一种能够处理大密度比(large density ratio)的多相流混合算法.流场信息通过格子波尔兹曼方法(lattice Boltzmann method,LBM)获得;相界面通过直接求解Cahn-Hilliard(C-H)方程确定.为保证在大密度比情况下求解界面方程的稳定性,采用二阶迎风格式来离散方程的对流项.通过对Rayleigh-Taylor(R-T)不稳定、液体中的气泡上升及液滴撞击干燥壁面的数值模拟,验证了方法的可行性.

     

    Abstract: In the framework of diffuse interface method (DIM), an efficient hybrid method for muhiphase flows with large density ratios is proposed. Lattice Boltzmann method is employed to obtain information of flow field. Cahn-Hilliard (C-H) equation is directly solved to identify the interface. In order to maintain stabihty of calculation at large density ratios, convection term of C-H equation is discretized by using second order unwind scheme. Numerical simulations of Rayleigb-Taylor (R-T) instability, bubble rising in liquid and droplet impact on a dry surface are implemented. The results agree well with data in literature.

     

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