Modelling of condensation at spherical expansion of water vapor into vacuum

The mathematical model of water vapor condensation was developed for the direct simulation Monte Carlo method. This model describes a chain of reactions providing formation and decay of water clusters with consideration of accompanying energy transfer processes. One-dimensional expansion of water vapor into vacuum from an evaporating spherical surface was studied numerically within the range of parameters, corresponding to the flows transitional by the Knudsen number. The influence of condensation on the gas-dynamic pattern of the flow, including the parameters of the Knudsen layer, is discussed. The work was financially supported by the Russian Foundation for Basic Research (Grant No. 07-01-00354-a).