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 Dp50=0.5–3.3 μm. 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.