Numerical Simulation of Heat Transfer and Evaporation During Impingement of Drops onto a Heated Wall

In this study, hydrodynamics and heat transport during the impact of single and multiple drops onto a hot wall are studied numerically. The heat transfer in the vicinity of the three-phase contact line, where solid, liquid and vapour meet, contributes significantly to the global heat transfer. The microscale processes in the region of the three-phase contact line are analysed using a lubrication approximation. The results in the form of correlations are integrated into an overall model. The impingement of drops on a macro scale is simulated using a numerical model developed within the OpenFOAM library. The influence of dimensionless parameters, i.e., the Reynolds, Weber, Bond, Prandtl and Jakob numbers, as well as the influence of pressure, on the transport phenomena is discussed. The analysis of the influence of drop frequency and substrate thickness during the vertical coalescence and the influence of the drop spacing during the horizontal coalescence of drops on the hot surface complete the study. The results contribute to a better understanding of the complex mechanisms of spray cooling