AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Enhanced Growth of n-propanol Nanodroplets in the Free Molecular Regime
YENSIL PARK, Shinobu Tanimura, Barbara Wyslouzil, The Ohio State University
Abstract Number: 704 Working Group: Aerosol Physics
Abstract Investigations by Pathak et al. [Aerosol Sci. Technol., 2013, 14, 1310-1324] on the growth of nanodroplets in a supersonic nozzle, found that for nonane experimental and theoretical non-isothermal growth rates agreed quantitatively when condensation (q$_c) and evaporation coefficient (q$_e) were both equal to 1. In contrast, for D$_2O nanodroplets, quantitative agreement between experiment and theory during rapid particle growth was only achieved by reducing the evaporation coefficient to ~0.5 while maintaining q$_c = 1. One concern with the D$_2O experiment was that the droplets were highly supercooled, thereby introducing uncertainty into the analysis since the physical properties for D$_2O were extrapolated by up to 50K below the equilibrium melting point. Here we report on similar experiments conducted with n-propanol under conditions where droplets are not supercooled. As was observed for D$_2O, we find that setting q$_c=q$_e=1 yields theoretical droplet temperatures up to ~4K lower than those estimated from mass and energy balances, and growth rates that are distinctly below those observed experimentally. Again, better agreement was found by setting q$_e=0.6 with q$_c= 1.0 or, alternatively, setting q$_c=~1.3 and q$_e = 1.0. Possible reasons for these differences will be discussed.