Evaporation kinetics of polyol droplets: determination of evaporation coefficients and diffusion constants

Yong-yang Su, Aleks Marsh, Allen Haddrell, Zhi-Ming Li, Jonathan Reid

Research output: Contribution to journalArticle (Academic Journal)peer-review

9 Citations (Scopus)
249 Downloads (Pure)

Abstract

In order to quantify the kinetics of mass transfer between the gas and condensed phases in aerosol, physicochemical properties of the gas and condensed phases as well as kinetic parameters (mass/thermal accommodation coefficient) are crucial for estimating mass fluxes over a wide size range from the free-molecule to continuum regimes. In this study, we report measurements of the evaporation kinetics of droplets of 1-butanol, ethylene glycol (EG), diethylene glycol (DEG) and glycerol under well-controlled conditions (gas flow rates, temperature) using the previously-developed cylindrical electrode Electrodynamic Balance (EDB) technique. Measurements are compared with a model that captures the heat and mass transfer occurring at the evaporating droplet surface. The aim of these measurements is to clarify the discrepancy in the reported values of mass accommodation coefficient (αM, equals to evaporation coefficient based on microscopic reversibility) for 1-butanol, EG and DEG, and improve the accuracy of the value of the diffusion coefficient for glycerol in gaseous nitrogen. The uncertainties in the thermophysical and experimental parameters are carefully assessed, the literature values of the vapour pressures of these components are evaluated and the plausible ranges of the evaporation coefficients for 1-butanol, EG and DEG as well as uncertainty in diffusion coefficient for glycerol are reported. Results show that αM should be greater than 0.4, 0.2 and 0.4 for EG, DEG and 1-butanol, respectively. The refined values are helpful for accurate prediction of the evaporation / condensation rates.
Original languageEnglish
Pages (from-to)12317-12334
Number of pages18
JournalJournal of Geophysical Research: Atmospheres
Volume122
Issue number22
Early online date22 Nov 2017
DOIs
Publication statusPublished - 27 Nov 2017

Keywords

  • evaporation kinetics
  • polyol droplets
  • electrodynamic balance (EDB)
  • evaporation coefficients
  • diffusion constants

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