Analysis of the Total Heat Transfer in an Evaporating Thin Film

When a liquid wets a solid wall, the extended meniscus may be divided into three regions: a non-evaporating region where liquid is adsorbed on the wall; a thin-film region where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region where capillary forces dominate. In this work, a simplified model based on the augmented Young-Laplace equation is developed and an analytical solution is obtained to more easily evaluate the total heat transfer in the thin-film region. The results are consistent with previously published numerical solutions. The present work is valid for a much wider range of fluid thermal conductivity than a previous analytical solution by Schonberg et al, which is only applicable for fluids with very low conductivity.