Computer simulation of the effect of particle stiffness coefficient on the particle-fluid flows

Abstract

The Computational fluid dynamics (CFD)–discrete element method (DEM) numerical simulation may be applied to predict the hydrodynamic behavior of dense particle–fluid flows. The main drawback of this simulation is the long computational time required owing to the large number of particles and the minute time-step required to maintain a stable solution. In this work, a new method to improve the efficiency and accuracy of CFD–DEM simulations is presented. The particle stiffness coefficient is used as a flexible parameter to improve the accuracy and efficiency of the model. The particle concentration distribution results are compared with experimental one’s to derive the optimum effective stiffness coefficient of particles for CFD-DEM simulations. The comparisons of the results indicate that although the application of stiffness coefficients with moderate values causes normal penetration depths of up to the particle radius, the simulations still show good results. The results also show that the stiffness coefficient and time step are strongly dependent of the fluid inlet velocities, particle diameters, particle inlet concentration and fluid type, and the simulation accuracy decreases greatly with increasing the time steps.