Modeling and numerical simulation of particulate flows by the Eulerian-Lagrangian approach

In this paper we present an Eulerian-Lagrangian numerical simulation (LNS) scheme for particulate flows. The overall algorithm in the present approach is a variation of the scheme presented earlier. In this numerical scheme w e solve the fluid phase continuity and momentum equations on an Eulerian gr id. The particle motion is governed by Newton's law thus following the Lagr angian approach. Momentum exchange from the particle to fluid is modeled in the fluid phase momentum equation. Forces acting on the particles include drag from the fluid, body force and the interparticle force that prevents t he particle volume fraction from exceeding the close-packing limit. There i s freedom to use different models for these forces and to introduce other f orces. In this paper we have used two types of interparticle forces. The ef fect of viscous stresses are included in the fluid phase equations. The vol ume fraction of the particles appear in the fluid phase continuity and mome ntum equations. The fluid and particle momentum equations are coupled in th e solution procedure unlike an earlier approach. A finite volume method is used to solve these equations on an Eulerian grid. Particle positions are u pdated explicitly. This numerical scheme can handle a range of particle loa dings and particle types. We solve the fluid phase continuity and momentum equations using a Chorin-type fractional-step method. The numerical scheme is verified by comparing results with test cases and experiments. (C) 2001 Elsevier Science Ltd. All rights reserved.