An incompressible three-dimensional multiphase particle-in-cell model for dense particle flows

A three-dimensional. incompressible, multiphase particle-in-cell method is presented for dense particle flows. The numerical technique solves the gove rning equations of the fluid phase using a continuum model and those of the particle phase using a Lagrangian model. Difficulties associated with calc ulating interparticle interactions for dense particle Rows with volume frac tions above 5% have been eliminated by mapping particle properties to an Eu lerian grid and then mapping back computed stress tensors to particle posit ions. A subgrid particle, normal stress model for discrete particles which is robust and eliminates the need for an implicit calculation of the partic le normal stress on the grid is presented. Interpolation operators and thei r properties are defined which provide compact support, are conservative, a nd provide fast solution for a large particle population. The solution sche me allows for distributions of types. sizes, and density of particles, with no numerical diffusion from the Lagrangian particle calculations. Particle s are implicitly coupled to the fluid phase, and the fluid momentum and pre ssure equations are implicitly solved, which gives a robust solution. (C) 2 001 Academic Press.