Thermal modeling with diffusion for dropwise condensation of humid air

摘要

This work develops a full thermal model to address dropwise condensation on a highly hydrophobic inclined surface. The thermal model includes thermal resistance due to the surface, droplet, liquid-vapor interface, capillary effect, and diffusion. Using published data, the model was validated for a vertical surface at a temperature difference of 10 °C. Unlike the existing models, the model developed in this paper includes an equivalent thermal resistance associated with diffusion. In addition to the equivalent thermal resistance associated with diffusion, this model includes the impact of coalescence and mass collection. The inclusion of these factors eliminates the need to make assumptions about the droplet profile on the surface. The model also includes the effect of nucleation, which can be reduced due to highly hydrophobic surfaces. The model requires a fixed maximum deviation from the surface boundary layer, maximum change in surface contact angel for droplet growth, and a time interval for nucleation. At experimental conditions, these parameters were verified to be 0.1% of the boundary layer thickness, 0.001 radians, and 1 s respectively.