A model calculation of particle deposition onto a rough wall by Brownian and turbulent diffusion

Abstract

A model, in which the particle number concentration above a rough wall is predicted based on the turbulence distribution near the wall, has been developed in order to theoretically evaluate the influence of the wall roughness upon Brownian and turbulent diffusive deposition of particles. Measurements of particle deposition rates onto rough walls have also been carried out using model surfaces of regularly shaped roughness affixed to the inner wall of a stirred tank. The dependence upon particle size, turbulent intensity, and roughness size of the enhancement of deposition due to a rough surface has been studied. From the model calculation of deposition rates accounting for the shape and configuration of the roughness elements, the model proposed is found to give good agreement with the measurements for surfaces with regularly shaped roughness as well as for irregular sandpaper surfaces.

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