Three-dimensional heat transfer simulation of a non-Newtonian droplet considering the effects of surface evaporation

In this study, the problem of falling a non-isothermal non-Newtonian droplet has been investigated numerically. The geometry of the problem is considered in three-dimensional form. The widely used power-law model (n=0.1) has been used to investigate the non-Newtonian behavior of the droplet. COMSOL software has been selected for the numerical simulation of motion and heat transfer of non-Newtonian droplets. The results of this research have been compared with previous similar works and have been successfully validated. The simulations show that considering the surface evaporation compared to the case without considering the surface evaporation can change the temperature of the droplet up to a significant amount of 10°C. Factors affecting surface evaporation, including fluid velocity and droplet temperature, have been investigated in detail. The results show that fluid velocity is the most important factor in changing the amount of surface evaporation of the droplet. By doubling the drop's velocity, its temperature drops by 8°C. Investigating the mechanism of movement and heat transfer of non-Newtonian drops can have significant applications in various processes used in printing, dyeing, and especially pharmaceutical industries.