Reynolds number and humidity dependency of dropwise condensation in moist convective air flows

Abstract

In moist air flows with phase transition is the convective flow strongly influenced by the sensible and the latent heat transfer. Additionally, the droplet shape (contact angle), the surface properties and the spatial distribution of the droplets also have a strong influence. Hence, empirical models or numerical calculations often fail to predict the heat and mass transfer due to the large number of parameters and the mutual interplay of the different heat transport mechanisms. To obtain a reliable prediction of the mass and the heat transfer, time-consuming and cost-intensive experiments or computationally expensive numerical simulations are necessary. Neither is feasible in the development and design process for industrial applications. It would be too costly and time consuming. Therefore, the method of predicting the droplet size distribution and the corresponding heat transfer by means of a scalar model is of vital interest. To overcome this issue we have been developing a prediction model based on the scaling of system characteristic numbers. Part of this approach is to investigate the effect of large-scale flow structures on the dynamics of the droplet size distribution and the corresponding sensible heat transfer and the condensation mass transfer