Molecular gasdynamics and chemical kinetics of vapour condensation

A filmwise nonequilibrium condensation of vapor consisting of polyatomic molecules, on the endwall of a shock-tube behind a reflected shock wave, is treated. It is shown that there exists a temporal transition phenomenon on the growth of a liquid film. The film grows approximately in proportion to the time in the early time stages, and after a transition period, it does asymptotically in proportion to the square root of the time. From the comparison between experiment and theory, the condensation parameter and the condensation coefficient of the vapor are deduced. The transition state theory has also shown that the parameter and coefficient are significantly less than those for the complete capture of molecules because of the hindrance of the rotational degrees of freedom of the molecules in the liquid state.