Large-Eddy Simulation With Simplified Collisional Microdynamics in a High Reynolds Number Particle-Laden Channel Flow

Abstract

Computing high Reynolds number channel flows laden by heavy solid particles requires excessive CPU resources to calculate interparticle collisions. Since the frequency of these collisions is high, the kinematic details of each elementary collision may not be essential when calculating particle statistics. In this paper, the dynamics of a particle with a phase trajectory that is discontinuous (due to collisions) is simulated using a hypothetical “noncolliding” particle moving along a trajectory smoothed over interparticle collisions. The statistical temperature of this particle is assumed to be in equilibrium with the statistical “temperature” of the resolved turbulence. This simplified microdynamic is introduced into ballistic calculations of particles within the framework of the “two-way” LES approach. The simulation was conducted specifically to compare the velocity statistics of the hypothetical particle with statistics yielded by measurements in the gas∕particle channel flow and by the LES∕particle approach where binary collisions were simulated. This paper shows that, by assuming the universality of collisional microdynamics, one may predict the experimental observation and the results of detailed simulations without requiring supplementary CPU resources to compute the binary collisions.