Enhanced Deposition of Suspended Particles to Fibrous Surfaces from Turbulent Gas Streams

Abstract

Deposition of aerosol particles to fibrous surfaces in turbulent duct flows is analyzed as a two stage process, consisting of eddy transport of particles from the mainstream and filtration by the fibrous elements. The theory applies to surfaces covered with a low density of fibrous elements extending into the viscous or the transition sublayers and reduces to the Friedlander and Johnstone theory (1957) for the case of a smooth surface. Deposition rates were calculated and compared with experimental data of Wells and Chamberlain (1967). Theory and experiment both show enhancement of deposition by a factor of 10 to 1000, compared to smooth surface deposition. Agreement between theory and experiment is satisfactory. Data from the literature show a very small increase in pressure drop for surfaces covered with low density fibers. The process is potentially useful for enhancement of deposition of particles or that of high Schmidt number mass transfer.