Experimental study of heat and mass transfer in convective flows of moist air with droplet condensation in function of surface roughness and wetting properties

Kurzfassung

Condensation and evaporation of droplets on an overflowed cool surfaces is a phenomenon which occurs in our everyday life, many technical applications and nature. For instance we well know the effect of misted windscreens in cars or the droplet condensation on the surface of heat exchangers. The heat transfer in convective flows with moist air is determined by the physical mechanisms convection, phase transition and vapour diffusion as well as the boundary conditions surface roughness and the contact angle between the droplets and the surface. Moreover, during the phase change latent heat is released or consumed, which in turn influences the heat transfer. The aim of the present study is to determine the impact of surface roughness and droplet’s contact angle on the mass transfer due to phase transition in mixed convective air flows.