Homogeneous Nucleation of Water Vapor with and without Carrier Gases in a Shock Tube,

摘要

Water vapor condensation is investigated by pressure and light scattering measurements in an expansion wave in the driver section of a shock tube. With this technique,onset conditions of homogeneous nucleation in pure water vapor (steam) and with small mole fractions of H2O within different carrier gases were obtained. Nucleation rate calculations are carried out with a non-isothermal pre-exponential term applied to the classical nucleation rate theory. Results for the transition region of pure vapor and small fractions of water vapor in argon,helium or air demonstrate the dependence of onset conditions on the mass fraction of the carrier gas. (Modified author abstract)