Feiguo Chen

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

Abstract 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.

Multi-scale Continuum-Particle Simulation on CPU–GPU Hybrid Supercomputer

This chapter serves as an introduction to the supercomputing works carried out at CAS-IPE following the strategy of structural consistency among the physics in the simulated systems, mathematical model, computational software expressing the numerical methods and algorithms, and finally architecture of the computer hardware (Li et al., From multiscale modeling to Meso-science—a chemical engineering perspective, 2012; Li et al., Meso-scale phenomena from compromise—a common challenge, not only for chemical engineering, 2009; Ge et al., Chem Eng Sci 66:4426–4458, 2011). Multi-scale simulation of gas-solid flow in continuum-discrete approaches and molecular dynamics simulation of crystalline silicon are taken as examples, both making full use of CPU-GPU hybrid supercomputers. This strategy is demonstrated to be effective and critical for achieving good scalability and efficiency in such simulations. The software and hardware systems thus designed have found wide applications in process engineering.