Parameters determining kinetic processes on an evaporation surface

Using the previously obtained relations for the velocity distribution function of evaporating particles, the evaporation coefficient has been calculated and the measured condensation coefficient and temperature jump determined near the evaporation surface have been estimated. The evaporation coefficient is ˜0.8, which is in good agreement with the data in the literature. The condensation coefficient determined as the proportionality factor in the Hertz formula is a conventional parameter, the value of which is varied depending on many factors. In the absence of evaporation, the condensation coefficient is approximately unity, whereas at a moderate evaporation flow this value decreases by a factor of about two. The temperature jump near the interface surface measured in many experimental studies has nothing to do with the real temperature difference between the liquid and the vapor. The measurable temperature jump has been determined in this study; it is about 10 K near the surface and depends on the distance to the measuring thermocouple placed in gas in each specific experiment.