A Coupled Lattice Boltzmann Method and Discrete Element Method for Discrete Particle Simulations of Particulate Flows

摘要

Discrete particle simulations are widely used to study large-scaleparticulate flows in complex geometries where particle-particle andparticle-fluid interactions require an adequate representation but thecomputational cost has to be kept low. In this work, we present a novelcoupling approach for such simulations. A lattice Boltzmann formulation of thegeneralized Navier-Stokes equations is used to describe the fluid motion. Thispromises efficient simulations suitable for high performance computing and,since volume displacement effects by the solid phase are considered, ourapproach is also applicable to non-dilute particulate systems. The discreteelement method is combined with an explicit evaluation of interparticlelubrication forces to simulate the motion of individual submerged particles.Drag, pressure and added mass forces determine the momentum transfer byfluid-particle interactions. A stable coupling algorithm is presented anddiscussed in detail. We demonstrate the validity of our approach for dilute aswell as dense systems by predicting the settling velocity of spheres over abroad range of solid volume fractions in good agreement with semi-empiricalcorrelations. Additionally, the accuracy of particle-wall interactions in aviscous fluid is thoroughly tested and established. Our approach can thus bereadily used for various particulate systems and can be extendedstraightforward to e.g. non-spherical particles.