Chemical Engineering Science, Vol.55, No.24, 6097-6107, 2000
A sublayer model for deposition of nano- and micro-particles in turbulent flows
Deposition of aerosol particles from 10 nm to 50 mum in turbulent duct flows is studied. The sublayer model for the turbulent deposition process is extended to cover the effects of gravity, Brownian, and lift forces. The model is based on the detailed analyses of particle trajectories in turbulence coherent structures near a wall. The Stokes drag, the Saffman lift, and the Brownian excitation are included in the particle equation of motion. Limiting trajectories for various conditions are evaluated, and the deposition Velocity for a range of particle relaxation times and flow conditions are presented. In particular, a new method for evaluating the deposition Velocity of Brownian particles based on the limiting trajectory concept is presented. Effects of flow shear velocity on the deposition rates of different size particles are also studied.