Flow Structure near an Evaporation Surface

The vapor flow near an interphase surface is studied by solving jointly the kinetic Boltzmann equation and the equations of continuum mechanics in the case of evaporation. It is shown that the flow structure formed in this case represents the totality of several zones, namely, the kinetic nonequilibrium region (Knudsen layer), the uniform flow region, where the velocity, density, and temperature are coordinate-independent, the contact discontinuity, and a region of uniform flow behind a closing shock wave. An approach is proposed, which makes it possible to construct the flow structure in the case of time-dependent evaporation without solving the kinetic Boltzmann equation. The results of the application of this approach are compared with numerical calculations obtained using the joint solution of the kinetic Boltzmann equation and the continuum mechanics equations and also by means of the direct statistical Monte Carlo simulation.