The Thermophoretic deposition was investigated theoretically and experimentally using monodisperse submicron solid NaCl aerosols in an annular flow with thermal gradients between two cylinders, in cryogenic temperature range. Also to check the present experimental method reasonable or not , researches were accomplished in high temperature range. The governing equations include the momentum and energy equations for the gas phase and the general dynamic equation (GDE) for the particle phase. Aerosol mechanisms included in the GDE are convection, Brownian diffusion and thermophoresis. The solution was derived based on an implicit finite difference approach.
Experimental quantification of thermophoretic deposition was carried out in a thermal cell consisting of two concentric cylinders. The measurements were with monodisperse NaCl aerosol using Differencial Mobility Analyzer (DMA) and Condensation Particle Counter (CPC). It was shown that thermophoretic deposition decreases with increasing particle size.
Comparison between experiments and simulations showed interesting phenomena. Well known thermophoresis theories by Derjaguin(1965), Talbot(1980) could expect thermophoretic deposition in high temperature range, but could not expect thermophoretic deposition in cryogenic temperature range.
It was found that the difference between results by calculation and by experiment is large.
So, new theoy about thermophoresis in cryogenic temperature was necessary and suggested empirically.
