Chemical Engineering and Processing, Vol.79, 14-22, 2014
Analysis of gas-particle flow characteristics in impinging streams
A three dimensional Euler-Lagrange model for the gas-particle two-phase impinging streams (GPIS) is developed based on the direct simulation Monte Carlo (DSMC) method with consideration of particle rotation and collision. The gas-particle flow characteristics involved in GPIS as well as the effects of inlet gas velocity and particle rotation are analyzed. The results indicate that two pairs of counter-rotating gas vortices are developed at two sides of the opposite jet flows, which is able to entrain the particles and thus greatly weaken the deposition of particles. Interparticle collisions in the impingement zone produce two effects on the particle behaviors: the direct escaping of particles from impingement zone and the progressive accumulation of particles in impingement zone. Under the same inlet particle mass flow rate, the particle concentration in the impingement zone decreases with increasing inlet velocity of gas due to the increasing impinging reaction of interparticle collisions and growing entrainment of gas vortices. In addition, the rotation of particle provides an additional driving force to push the particles away from the impingement zone, leading to the higher speed of escaping particles and smaller maximum particle concentration at the center of impingement zone than those without particle rotation. (C) 2014 Elsevier B.V. All rights reserved.