Evaporation and movement of fine droplets in non-uniform temperature and humidity field

Abstract Droplets are a typical pollutant in industrial plants and their evaporation and movement characteristics are closely related to their surroundings. Because saturated moist air is emitted to the surrounding environment, the resulting flow field depends ultimately on the source temperature and ambient relative humidity. These two parameters in practical production processes typically change with the process. This study presents the numerical simulations of the dispersion process of fine water droplets in a non-uniform field, where the source temperature (298–353 K), ambient relative humidity (0–80%) and droplet size (20–80 μm) are selected as the control variables. Under the influence of non-uniform field quantities, the water vapor concentration at the droplet surface can no longer be maintained constant. Thus, it is necessary to modify it using user-defined functions. The results indicate that the influence of these three factors on the evaporation characteristics of droplets are not isolated, and it is impossible to discuss the influence of residual factors without any one of them. However, except for isothermal conditions, these three factors appear to be independent of each other in terms of movement characteristics. Our study can facilitate the improvement of fine control levels in an industrial building environment.