A unified Eulerian theory of turbulent deposition to smooth and rough surfaces

摘要: Abstract This paper presents a simple, unified theory of deposition that is applicable for particles any size, and reproduces very closely experimentally measured variation in velocity with particle relaxation time. Apart from providing physical insight, the offers fast reliable computational tool practical use to aerosol engineers. The predictions are at least as accurate state-of-the-art particle-tracking calculations but require much less includes effects thermophoresis, turbophoresis, electrostatic forces, gravity, lift force surface roughness. consists writing continuity momentum conservation equations their proper form then performing Reynolds averaging. procedure results an expression flux which three distinct terms each clear interpretation available. first term diffusive due Brownian motion turbulent fluctuation, second temperature gradient (thermophoresis), third convective arises primarily interaction between inertia inhomogeneity fluid turbulence field (turbophoresis). forces also contribute this flux. It shown it crucial include equation analysis gives estimate mentioned slip particles. Absence many previous studies included only necessitated postulations such stopping distance models. Only dominant retained present give almost same answer calculation retaining all terms, former more amenable direct interpretation. method averaging general, other not study, e.g. pressure diffusion can easily be incorporated by including appropriate equation. study roughness, show presence small roughness even hydraulically smooth regime significantly enhances especially Thermophoresis have equally strong effects, modest difference wall bulk fluid. For intermediate size range, thermophoresis important contributors overall rate.