Author(s): Holyst, Robert and Litniewski, Marek
Title: Evaporation into vacuum: Mass flux from momentum flux and the Hertz-Knudsen relation revisited
Abstract: We performed molecular dynamics simulations of liquid film evaporation vacuum for two cases: free evaporation without external supply of and evaporation at constant average liquid temperature. In both we found that the pressure inside a liquid film was constant, temperature decreased and density increased as a function of from the middle of the film. The momentum flux in the vapor far the liquid was equal to the liquid pressure in the evaporating Moreover the pseudopressure (stagnation pressure) was found to be in the evaporating vapor and equal to the liquid pressure. The flux and its relation to the pressure determined the number of molecules per unit time and as a consequence the mass flux. We found a simple formula for the evaporation flux, much better describes simulation results than the commonly used Hertz-Knudsen relation.
Journal: JOURNAL OF CHEMICAL PHYSICS
Volume: 130
ID: ISI:000263599300033
Year: 2009
DOI: 10.1063/1.3077059