A Review on Thermo-Fluidic Study of Droplet Impact in Spray Cooling

Abstract

Spray cooling exhibits outstanding cooling performances compared to other liquid cooling techniques, which offers robust thermal management for numerous applications facing high heat flux challenges. In spray cooling, coolant droplets generated from a spray nozzle continuously impinge onto a hot surface at high flow rates. The interaction between the droplets and the surface - whether they land on a pre-existing liquid film or directly on the heated area - depends on the fluid saturation temperature and the surface temperature. Understanding the dynamics and heat transfer during droplet impact is crucial for advancing spray cooling research. The present work summarizes the recent advancements in the study of droplet impact dynamics and heat transfer in spray cooling from two aspects. The first aspect is about the statistical analyses of droplet behaviors and liquid film conditions in spray cooling, examining their influence on cooling efficiency. The second one is regarding the droplet-surface interactions in spray cooling, ranging from single droplet to spray by increasing the complexity of droplet condition and surface condition. It includes the single droplet impacting a dry heated surface, multiple droplets impacting a dry heated surface, and droplets impacting the heated flowing film.