Effect of a Hydrophobic Coating on the Local Heat Transfer Coefficient in Forced Convection under Wet Conditions

Abstract

An estimation technique of the local heat transfer coefficient, based on the solution of the 2-D inverse heat conduction problem, has been adopted in order to investigate the effect of the surface wettability on the two-phase convective heat transfer in a dehumidifying process. The convective heat transfer coefficient distribution has been restored on aluminum plates coated with a hydrophobic oleic film on which the dropwise condensation of the water vapor carried by a humid air turbulent stream occurs. The refinement of the technique in relation to its ability of capturing the heat transfer local capability of the surface enables the appraisal of the heat transfer augmentation due to the hydrophobic surface coating.

Keywords:

• local heat transfer coefficient
• parameter estimation
• surface condensation
• surface treatments
• dehumidifying processes