~ ) Pergamon 0021-8502(95)00052-6 J. AerosOl Sci., Vol. 27, No. t, pp. 41 59, 1996 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All rights reserved 0021 8502/96 $15.00 + 0.00 GAS-SOLID FLOW WITH THE SLIP VELOCITY OF PARTICLES IN A HORIZONTAL CHANNEL Medhat Hussainov, Alexander Kartushinsky, Anatoly Mulgi and tJlo Rudi* Institute of Energy Research, Estonian Academy of Sciences, Paldiski Rd, 1, EE-0001, Tallinn, Estonia (First received 22 February 1994; and in final form 5 June 1995) Abstract--The behavior of solid inertia particles carried with significant slip velocity in turbulent gas-solid flow in a horizontal channel is investigated. Our mathematical analysis shows that, for such motion, particles have substantial transversal velocity and so they interact intensively with the walls when the Stokes number exceeds a threshold value. The mathematical description of such motion of particles is based on consideration of two particle flows moving towards each other from opposite walls and traversing through the center of the channel. The transport equations of particle mass and linear and angular momenta are integrated along the whole width of the channel. It was found that the Magnus lift force (in addition to the drag force) plays a significant role in the transversal motion of particles. The calculations on the motion of particles with various size in channels of different width for different velocities of the carrier flow show that the model presented does describe a two-phase flow with the slip velocity. Regardless of the fact that our experimental results were obtained for a pipe and the calculations, by contrast, were carried out for a fiat channel, the numerical results for the velocity distribution of both phases, as well as that for the slip velocity, are in good agreement with experimental ones. Some discrepancy is found only for the description of particle mass concentration. Our model for a fiat channel describes almost uniform distribution of particle mass concentration while our experiments, by contrast, show a gradient distribution fading towards the pipe wall. Apparently this results from the influence of the wall curvature of the pipe. NOMENCLATURE B channel width Cb drag coefficient for dispersed phase d particle diameter d nondimensional particle diameter D pipe diameter f7 numerical code in finite difference Fo drag force Fra Magnus force hb grid step of buffer layer ha grid step of laminar sublayer ht grid step of turbulent core k turbulent energy k, restitution coefficient k~ friction coefficient l interparticle distance mp particle mass N number of particles Nb number of calculating points in buffer layer N~ number of calculating points in laminar sublayer Nt number of calculating points in turbulent core P pressure r generator of a cone Re Reynolds number Re. friction Reynolds number Res Reynolds number for dispersed phase Ret turbulence Reynolds number Stk. Stokes number TL Lagrangian integral time scale u streamwise mean velocity Up particle streamwise velocity after collision v transversal mean velocity v. friction velocity * Corresponding author. 41