Thermocapillary rupture of liquid films due to Marangoni convection, which is caused by thermally induced surface tension gradients along the liquid–gas interface, is examined. It is shown that the critical temperature difference at the free boundary required for rupture increases with the film thickness due to the competition between thermocapillary forces and gravity. The analysis also includes the effects of evaporation and liquid redistribution during heating. Based on our own and published data, a correlation is obtained for the first time to describe the rupture threshold in terms of the critical Marangoni number and the dimensionless film thickness. The proposed correlation allows for the prediction of film rupture conditions over a wide range of physical parameters, which is of importance for preventing critical phenomena in film cooling technologies.
Kochkin et al. (Thu,) studied this question.