On the deposition of aerosol particles on cylinders in turbulent cross flow

The classical method of modelling the deposition of aerosols on cylinders and spheres in cross flow has been made in terms of inertial impaction, interception and Brownian diffusion. Recent experimental results in a wet scrubber and on single wires in turbulent cross flow yielded substantially higher collection efficiencies than predicted by the classical mechanisms. To explain the increased collection efficiency, it is necessary to consider eddy diffusion as a prime mechanism. Based on the concept of eddy diffusivity and the continuum concept of a gas-solid system, a turbulent diffusion model was developed to simulate the experimentally observed deposition rates. The model is essentially the solution of the continuity equation and equations of motion for the particles, with the assumption that within the boundary layer the fluid-particles closely follow the fluid streamlines. From physical reasoning, the eddy diffusivity profile across the boundary layer was assumed to have the same shape as that near a flat plate. The computed deposition rates were in good agreement with the experimental results.