NUMERICAL-SIMULATION OF DILUTE TURBULENT GAS-SOLID FLOWS IN HORIZONTAL CHANNELS

A dilute turbulent gas-solid two-phase flow model is developed in the present study. Time-averaged conservation equations for mass and momen tum, and a two-equation k-e closure are used to model the quid phase. The solid phase consisting of inelastic, frictional, uniform spheres i s simulated by using a Lagrangian approach in which the particle traje ctories and velocities are determined by integrating the particle equa tions of motion. The fluid-solid coupling effects due to solid volume fraction and interfacial momentum interaction are incorporated in the simulation. A sticking-sliding collision model is employed for the par ticle-particle collisions and the particle-wall collisions. The two-ph ase model is implemented to simulate gas-solid suspensions in a horizo ntal channel. Substantial agreement is found between the simulation re sult and the experimental data for the fluid pressure gradient, the di stributions of mean gas velocity, mean particle velocity and concentra tion. For dilute systems with solids volume fraction of the order 10(- 3), interparticle collisions are found to be crucial in sustaining a s teady and fully developed suspension in the horizontal channel, while the Magnus lift due to particle rotation is found to play a significan t role as well. Detailed new numerical results for macroscopic propert ies such as Reynolds stresses, air turbulence intensities. particle fl uctuation kinetic energy, mean particle angular velocity, particle str esses and angular momentum fluxes are presented in the paper. (C) 1997 Elsevier Science Ltd.