On the dependence of a critical supersaturation on pressure of a two-component background gas in a diffusion cloud chamber

Itkin, A. L.

doi:10.1016/s0301-0104(98)00293-6

Cited by 8 publications

(3 citation statements)

References 8 publications

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“…Quite recently, Novikov et al studied this effect by a Monte Carlo simulation and found a strong decrease of nucleation rate with increasing pressure, though only for dense carrier gases. Their effect had the same magnitude as the one observed in TDCCs, but their prediction concerning the effect of carrier gas (He, H 2 ) is in contradiction with experimental observation by Heist et al A completely different approach to this problem was suggested by Itkin . He assumed that nucleation kinetics is controlled by the diffusion of the vapor molecules toward the cluster surface, formulated a nucleation theory based on this assumption, and outlined a new experiment for TDCC by which his theory might be proven.…”

Section: Introductionmentioning

confidence: 91%

2-D Model for the Description of Thermal Diffusion Cloud Chambers: Description and First Results

and¹,

Wilck²,

and³

et al. 2001

J. Phys. Chem. B

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In thermal diffusion cloud chambers (TDCCs), a decrease of nucleation rate with increasing total pressure was observed repeatedly, both near atmospheric pressures and at elevated pressures. Because this pressure effect was observed almost only using TDCCs, there have been some concerns inside the nucleation community whether it is not an experimental artifact. One questionable point in this context is that, to calculate the profiles of temperature and saturation ratio in TDCCs it is assumed that if the chamber is sufficiently “flat”, a 1-d model can be used for the description of the transport processes in the central part of the chamber. The major concern in this context is that the heated chamber wall may cause a buoyancy driven convection that can propagate toward the center of the chamber and cause a slow motion of the gas mixture. To investigate this effect, a 2-d model of coupled mass, heat, and momentum transport in TDCCs has been developed. In the paper this model is described, and its predictive force is shown in comparison with a state-of-the-art 1-d model and with experimental data from the system n-propanol−He. Furthermore, results concerning the effects of wall heating, total chamber pressure, carrier gas, and chamber geometry on nucleation rates are presented. The influence of wall heating on the nucleation rate was found to be significant when transport processes inside TDCC are dominated by buoyant convection. Using the 2-d model made it possible to partly (but not completely) explain the pressure effect observed in TDDCs. It was also shown that including the process of thermal diffusion in the model may have a significant influence on the resulting profiles of nucleation rate. It was confirmed that the choice of the carrier gas in the chamber can strongly influence stability of chamber operation. With respect to the optimal chamber geometry it was shown that TDCCs should have a diameter as small and a diameter-to-height ratio as large as possible to minimize the 2-d effects. All in all, it was proven that application of 1-d models to describe the heat and mass transfer in TDCC may lead to an erroneous determination of temperature, saturation ratio, and nucleation rate profiles.

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Section: Introductionmentioning

confidence: 91%

2-D Model for the Description of Thermal Diffusion Cloud Chambers: Description and First Results

and¹,

Wilck²,

and³

et al. 2001

J. Phys. Chem. B

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show abstract

“…If Kn v Ӷ1, the growth is in the continuum or diffusion regime. 19,23,24 Similarly, the motion of droplets is in free molecular regime if Knӷ1, and if KnӶ1, the motion of droplets is in the continuum regime. 24 Table I lists the mean free paths of 1-propanol vapor and He carrier gas over the pressure range of the data from Ref.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…It is necessary to emphasize that the intermolecular distance being smaller than the critical cluster is a more limiting condition than the condition used by Fisenko, where the mean free path of the vapor is of the same order of magnitude as the cluster size. 19 Recently another kinetic treatment of the pressure effect has been developed by Itkin,23 in which he attempted to find a correlation between relaxation processes in clusters, nucleation rate and the carrier gas pressure.…”

Section: Introductionmentioning

confidence: 99%

The effect of carrier gas pressure on vapor phase nucleation experiments using a thermal diffusion cloud chamber

Kane

Фисенко

Rusyniak

et al. 1999

The Journal of Chemical Physics

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Homogeneous nucleation rate measurements of 1-butanol in helium: A comparative study of a thermal diffusion cloud chamber and a laminar flow diffusion chamberThe effect of carrier gas pressure and wall heating on the operation of the thermal diffusion cloud chamberThe influence of buoyant convection on the operation of the upward thermal diffusion cloud nucleation chamber J. Chem. Phys. 111, 8013 (1999); 10.1063/1.480274Homogeneous nucleation rates of n-pentanol measured in an upward thermal diffusion cloud chamber Recent measurements of critical supersaturations for the vapor phase homogeneous nucleation of several substances using a diffusion cloud chamber technique exhibit a dependence on the pressure of the carrier gas used in the experiments. A model of droplet growth and motion in a diffusion cloud chamber, combined with the density and temperature profiles of the chamber is presented to explain the pressure dependent results. The model demonstrates that at higher carrier gas pressures the growth of the droplets is retarded and the optical scattering signal from the particles is reduced. It is concluded that the observed effect may not result from a pressure dependence of the nucleation rate, but from a pressure dependence of the droplet growth and motion.

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Distinctive features of phase transitions in the formation of nanosized aerosol particles

Levdanskii

Smolik

Ždı́mal

et al. 2008

J Eng Phys Thermophy

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On the dependence of a critical supersaturation on pressure of a two-component background gas in a diffusion cloud chamber

Cited by 8 publications

References 8 publications

2-D Model for the Description of Thermal Diffusion Cloud Chambers: Description and First Results

2-D Model for the Description of Thermal Diffusion Cloud Chambers: Description and First Results

The effect of carrier gas pressure on vapor phase nucleation experiments using a thermal diffusion cloud chamber

Distinctive features of phase transitions in the formation of nanosized aerosol particles

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