Particle Wall Loss Rates in Vessels

Crump, James G.; Flagan, Richard C.; Seinfeld, John H.

doi:10.1080/02786828308958636

Cited by 102 publications

(60 citation statements)

References 6 publications

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“…These processes should be minimized by using conductive and chemically inert materials, respectively. Bag size and shape also affects deposition processes, with the vertical dimension affecting gravitational losses and the shape determining the surface area to volume ratio and therefore, the diffusion wall deposition loss process 8,10 . Gravitational deposition is significant for larger particles (> 1 μm) and depends only on the bag dimensions and orientation.…”

Section: Introductionmentioning

confidence: 99%

Application of bag sampling technique for particle size distribution measurements

2009

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Bag sampling techniques can be used to temporarily store an aerosol and therefore provide sufficient time to utilize sensitive but slow instrumental techniques for recording detailed particle size distributions. Laboratory based assessment of the method were conducted to examine size dependant deposition loss coefficients for aerosols held in Velostat TM bags conforming to a horizontal cylindrical geometry. Deposition losses of NaCl particles in the range of 10 nm to 160 nm were analysed in relation to the bag size, storage time, and sampling flow rate. Results of this study suggest that the bag sampling method is most useful for moderately short sampling periods of about 5 minutes.

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Section: Introductionmentioning

confidence: 99%

Application of bag sampling technique for particle size distribution measurements

2009

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“…The most critical aw in the above coef cient is the evident inconsistency of the assumptions of complete convective mixing 711 outside the boundary layer and complete absence of convection within the boundary layer (Crump et al 1983). In fact, the diffusion boundary layer thickness was shown to depend on the particle size by an experimental study of Harrison (1979).…”

Section: Introductionmentioning

confidence: 99%

Wall Loss Rate of Polydispersed Aerosols

Park¹,

Kim²,

Han³

et al. 2001

Aerosol Science and Technology

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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).

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“…Deposition of ETS particles has been studied in research chambers under controlled conditions (Offermann et al, 1985;Ingebrethsen and Sears, 1989). Deposition rate is usually determined indirectly by measuring aging concentrations of suspended particles (Crump et al, 1983;Offermann et al, 1985;McMurry and Grosjean, 1985;Okuyama et al, 1986;Pandian and Friedlander, 1988;Ingebrethsen and Sears, 1989;Chen et al, 1992). Ligocki et al (1990) studied deposition by collecting particles on a carboncoated substrate and analyzing the samples with a scanning electron microscope.…”

Section: Introductionmentioning

confidence: 99%

Deposition of Tobacco Smoke Particles in a Low Ventilation Room

Nematollahi

Sextro

et al. 1994

Aerosol Science and Technology

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Deposition on indoor surfaces is an important removal mechanism for tobacco smoke particles. We report measurements of deposition rates of environmental tobacco smoke particles in a room-size chamber. The deposition rates were determined from the changes in measured concentrations by correcting for the effects of coagulation and ventilation. The airflow turbulent intensity parameter was determined independently by measuring the air velocities in the chamber. Particles These results were used to predict deposition of sidestream smoke particles on interior surfaces. Calculations predict that in 10 hours after smoking one cigarette, 22% of total sidestream particles by mass will deposit on interior surfaces at 0.03 air change per hour (ACH), 6% will deposit at 0.5 ACH, and 3% will deposit at 1 ACH.

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Particle Wall Loss Rates in Vessels

Cited by 102 publications

References 6 publications

Application of bag sampling technique for particle size distribution measurements

Application of bag sampling technique for particle size distribution measurements

Wall Loss Rate of Polydispersed Aerosols

Deposition of Tobacco Smoke Particles in a Low Ventilation Room

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