EULERIAN AND LAGRANGIAN SIMULATIONS OF PARTICLE DEPOSITION FROM A POINT SOURCE IN A TURBULENT CHANNEL FLOW

Abstract

ABSTRACT Results comparing Eulerian and Lagrangian simulations of particle deposition from a point source in a channel are presented. The mean turbulent flow field is simulated using a two-equation k-ϵ turbulence model. In the first, approach, diffusion of aerosol particles is studied by solving the corresponding advection-diffusion equation. Deposition of particles in the intermediate size range are analyzed by considering both the turbulent eddy diffusion and the eddy impaction processes, as well as the Brownian diffusion effects. In the second approach, the turbulence fluctuating velocity field are numerically simulated as a Gaussian random process. The Lagrangian trajectories of aerosol particles in the channel are then evaluated by solving the corresponding particle equation of motion. Effects of Brownian diffusion on particle motions are also included. A series of digital simulations for particles of various sizes which are released at different locations across the channel are carried out. Depositions of different size particles on the wall under a variety of conditions are analyzed. The relative significance of turbulence and Brownian effects are also discussed.