Homogeneous nucleation rate measurements in supersaturated water vapor

Abstract

The rate of homogeneous nucleation in supersaturated vapors of water was studied experimentally using a thermal diffusion cloud chamber. Helium was used as a carrier gas. Our study covers a range of nucleation rates from 3x10(-1) to 3x10(2) cm(-3) s(-1) at four isotherms: 290, 300, 310, and 320 K. The molecular content of critical clusters was estimated from the slopes of experimental data. The measured isothermal dependencies of nucleation rate of water on saturation ratio were compared with the prediction of the classical theory of homogeneous nucleation, the empirical prediction of Wolk et al. [J. Chem. Phys. 117, 10 (2002)], the scaled model of Hale [Phys. Rev. A 33, 4156 (1986)], and the former nucleation onset data.

Molecular dynamics simulations of the nucleation of water: Determining the sticking probability and formation energy of a cluster

“…In the case of water, the deviations between the nucleation rates predicted by the classical nucleation theory and the experimental values are in the order of 10 2 -10 3 . 6,13,18,[20][21][22][23][24][25][26][27] The nucleation rates obtained by molecular dynamics (MD) and Monte Carlo (MC) simulations also significantly differ from the predictions of the CNT. The nucleation rate is governed by the formation free energy of a critical cluster, which is the smallest thermodynamically stable cluster.…”

Communication: Tolman length and rigidity constants of water and their role in nucleation

“…This claim is supported by a comparison between the nucleation rates obtained by Brus et al using two different experimental techniques, showing similar deviations. 39,40 It is quite remarkable that the empirical formula by Wölk and Strey (crosses), which has been fitted to experiments, displays almost the same deviations with experimental results as a function of temperature, as c-CNT (diamonds); specially, taking into account that the curvature corrected CNT depends only on the Tolman length and the rigidity constants from SGT and has no a priori information about experimental nucleation rates. This strongly suggests that including the curvature dependence of the surface tension corrects the wrong temperature-dependence given by the classical theory, at least for the case of water.…”

“…We analyze their influence on water nucleation rates, by comparing to a large amount of experimental data from different experimental techniques covering a wide range of temperatures, supersaturations, and nucleation rates. 7,[38][39][40][41][42][43] An excellent overview of the available experiments on homogeneous water-nucleation was recently given by Wölk et al 44 Moreover, based on their experiments from 2001, Wölk and Strey devised an empirical formula for water to correct the predictions from CNT. 7 This formula, which we will use for comparison, has been found to correspond well with most of the experiments and has been adopted as a benchmark for homogeneous-water-nucleation.…”

Efficient solution methods for N-component condensation

“…nucleation pulse tubes, diffusion cloud chambers and expanding nozzle flows [33,72]). For continuously varying pressure-temperature profiles [8] all p, T -dependent functions -J, S , g(n) and ρ s (n) -become parametric functions of time.…”

“…[39,42]: The equilibrium calculations are facilitated by the introduction of the fugacity, f i , of component i in the mixture. The fugacity and chemical potential are related by 8) where the superscript 'ref' denotes an arbitrary reference state. The fugacity can be considered as a modified partial pressure where the effect of non-ideality of the mixture is accounted for.…”