Wall Loss Rate of Polydispersed Aerosols

Abstract

Wall loss rates of polydispersed aerosols in a stirred vessel were studied theoretically and experimentally. A formula for the polydispersity factor of the wall loss rate was derived using the moment method of log-normal size distribution and compared with numerical calculations. The representative theory of Crump and Seinfeld (1981) was used as the wall loss rate of monodispersed aerosols in which the Brownian diffusion, the turbulent eddy diffusion, and the gravitational settling are included as wall loss mechanisms. The results of the analysis show that the wall loss rate of a polydispersed aerosol is substantially higher than that based on a monodispersed size distribution model if the particle size distribution can be represented reasonably well by a log-normal function. The existing diagram showing the loss rate as a function only of the particle size was expanded to include the polydispersity effects. Experimental measurements of particle wall loss rate were performed by observing the time-dependent changes in particle number concentration for various stirring intensities in a cylindrical stirred chamber. It was shown that by correcting for the polydispersity effect, the dependence of the wall loss rate on particle size and stirring intensity agreed with the theory of Crump and Seinfeld (1981).

New particle formation in the sulfuric acid–dimethylamine–water system: reevaluation of CLOUD chamber measurements and comparison to an aerosol nucleation and growth model

“…It is therefore possible that any amines present were not suitable for nucleation. Therefore, application of methods capable of amine speciation should be applied more widely in atmospheric measurements (Place et al, 2017). Several CLOUD papers reported particle formation rates for a diameter of 1.7 nm.…”

“…2). A weaker size dependence would lead to higher predicted particle concentrations at larger sizes (Park et al, 2001). However, no evidence was found from the existing CLOUD data that this is the case.…”

Effect of wall surface materials on deposition of particles with the aid of negative air ions

“…Crump and Seinfeld (1981) studied a wall deposition theory of particles in an enclosed vessel explained the motion of aerosol by turbulent transport, Brownian diffusion and gravitational sedimentation. Park, Kim, Han, Kwon, and Lee (2001) investigated the loss rate of polydispersed aerosols from a wall, correcting the model of Crump and Seinfeld (1981) for the polydispersity effects of polydispersed aerosols. Park et al (2001) found that the wall loss rate of polydispersed aerosols exceeded that of monodispersed aerosols.…”

“…Park, Kim, Han, Kwon, and Lee (2001) investigated the loss rate of polydispersed aerosols from a wall, correcting the model of Crump and Seinfeld (1981) for the polydispersity effects of polydispersed aerosols. Park et al (2001) found that the wall loss rate of polydispersed aerosols exceeded that of monodispersed aerosols. McMurry and Rader (1985) proposed a wall deposition theory of particles in spherical, electrically charged chambers, for aerosol moved by electrostatic drift, or exhibiting turbulent movement, Brownian diffusion and gravitational sedimentation.…”

Investigation on the coagulation and deposition of combustion particles in an enclosed chamber with and without stirring

“…Many studies were conducted in such a way on monodisperse aerosols to determine the deposition rate (Cheng, 1997;Holub, 1984;Morawska & Jamriska, 1996;Mosley et al, 2001;Okuyama, Kousaka, Yamamoto, & Hosokawa, 1986). The deposition of polydisperse suspensions of solid sodium chloride particles and liquid oleic acid droplets was investigated in Park, Kim, Han, Kwon, and Lee (2001) and Kim, Park, Song, Kim, and Lee (2003). The deposition of combustion particles was investigated by Mosley et al (2001) on polydisperse incense particles, and by Jamriska and Morawska (2003) on polydisperse cigarette smoke and petrol smoke.…”