Evaluation using an LES Database of Constitutive Relations for Fluid-Particle Velocity Correlations in Fully-Developed Gas-Particle Channel Flows

Models of the fluid-particle velocity correlation are evaluated in fully-developed particle-laden turbulent channel flow. The database for the model evaluations is generated using Large-Eddy Simulation (LES) of the carrier phase flow combined with Discrete Particle Simulation (DPS) for the dispersed phase. The current focus is on gas-solid flows for which the particle equation of motion includes the contribution from the drag force and the influence of particle momentum exchange on properties of the carrier phase is neglected. Three particle Stokes numbers are considered that provide a wide range in the particle response to the turbulent fluid motions. For each Stokes number, simulations are performed with and then without the influence of inter-particle collisions. Binary particle-particle collisions are considered that are assumed perfectly elastic. Models for the fluid-particle correlation are developed from the Lagrangian stochastic equations of Simonin et al. (1993) and Minier and Peirano (2001). The model evaluations are performed using an in medio approach in which some terms are supplied from the LES/DPS database with closures applied for the remaining terms. A coupled system of equations is then solved for the fluid-particle correlation tensor. The in medio evaluations show that the fluid-particle correlations predicted using the approach proposed by Simonin et al. (1993) are reasonably accurate for the parameter ranges considered. While the stochastic equation of Minier and Peirano (2001) also leads to reasonably accurate predictions of the fluid-particle correlation in flows without interparticle collisions, the model predictions are substantially less accurate in flows that include particle-particle collisions.