A Study of the Soft-Sphere Model in Eulerian-Lagrangian Simulation of Gas-Liquid Flow

Eulerian-Lagrangian method is becoming more and more popular for the simulation of dispersed multiphase flow as the computational ability grows. An important issue in this method is the handle of collisions. Until now, both hard-sphere and soft-sphere models have been used extensively in the simulation of gas-solid systems while in gas-liquid systems only the hard-sphere model is used. This study presents an investigation of the performance of the soft-sphere model in gas-liquid systems. The open source software OpenFOAM is utilized to complete our simulations. We simulated the 2D Becker case to give a preliminary study of the suitability of the soft-sphere model in gas-liquid systems. We tested the normal stiffness coefficient from 50 N/m to 0.01 N/m and found that the coefficient 1 N/m predicted sufficiently accurate flow field. In the simulation of 3D Deen case, we tried more stiffness coefficients and found that the soft-sphere model successfully predicted the fluid velocity, and the result at a normal stiffness coefficient of 1 N/m is the optimum. It can be expected that the soft-sphere model is also suitable in gas-liquid systems.