Interfacial heat transfer and boiling transition of the droplets on superheated surface with Leidenfrost effects

Abstract

This study, a novel three-dimensional (3D) method is developed to address the Leidenfrost effect issues with a focus on the synergies of droplet velocity (v) and surface temperature (Tw). Here, we proposed a 3D computational fluid dynamics numerical simulation that combines a VOF model and an amended evaporation model and performed high-speed video testing for capturing vapor dynamics details and distinguish anisotropic heat transfer on a high-temperature surface near the Leidenfrost point. The results revealed that the law of the dynamic Leidenfrost point (TDLT) was predominated by changes in the thickness and shape of the vapor layer. Additionally, coexistence of v and Tw produced a vapor layer, instantly disentangling the boiling state and initiating a gradual change from contact boiling to film boiling, with v affecting the boiling state transition and delaying buildup of the vapor layer aggregation. We determined the empirical correlation of TDLT with the Weber number (We) as follows: TDLT=376.65+84.45×We0.22. Moreover, the high Tw promoted vapor layer formation, thereby decreasing the heat transfer efficiency, whereas the large v inhibited vapor layer formation and enhanced interfacial heat transfer. These findings contribute to a better understanding of the theoretical basis for inhibiting the Leidenfrost effect.