Deposition layers formed by a turbulent aerosol flow of micron and sub-micron particles

The particle deposition layers formed by a turbulent aerosol flow have been studied as a simultaneous phenomenon of particle deposition and reentrainment. The experiments were conducted in a rectangular channel using alumina powders of D-p50 = 0.5-3.3 mum. The state of the deposition layer was observed through a video microscope, and the surface profiles were measured with a scanning laser focus displacement meter. The experimental results showed that micrometer-sized particles formed a striped-pattern deposition layer as well as a filmy deposition layer, while sub-micron particles only formed a filmy deposition layer; the difference in the formation of these deposition layers was described in detail. Furthermore, a theoretical analysis taking account of the balance of the adhesive strength and the separation strength was carried out to explain the thickness of the deposition layer. (C) 2001 Elsevier Science B.V. All rights reserved.