Evaporative heat transfer from thin liquid film on a heated cylinder

Simulating a porous surface that is partially saturated with a liquid, a two-dimensional meniscus attaching two adjacent cylinders with the same diameter is studied under heating and convective conditions. A thin liquid film model is presented to predict thin film thickness and evaporative heat transfer coefficient. Experiments are carried out to characterize the temperature and geometry of a liquid meniscus. The evaporating thin film length is determined from measured surface temperature and meniscus shape. The surface temperature data is correlated and used to derive the evaporative heat transfer coefficient with the aid of conjugate heat transfer using a finite element code. The results are compared reasonably with the thin film model. The effects of Bond number, spacing between cylinders and heating power on thin film geometry and heat transfer characteristics are discussed. Correlations to predict the evaporative heat transfer coefficient and ratio of evaporative heat transfer rate to total heat rate are presented.