Numerical study and experimental verification on spray cooling with nanoencapsulated phase-change material slurry (NPCMS)

Spray cooling is an efficient cooling method with high heatflux removal capability. In this study, we propose a spray cooling regime with nanoencapsulated phase-change material slurry (NPCMS), aiming to improve the coolant's heat capacity. We develop a three-dimensional model of spray cooling of NPCMS based on DPM and Lagrangian Wall Film (LWF) models. Also, the equivalent heat capacity method is integrated in LWF model to characterize the solid-liquid phase change of NPCMS. In addition, the experiment of spray cooling of NPCMS is conducted to verify our model. The influences of initial temperature of NPCMS and dynamic properties on flow and heat transfer of NPCMS are discussed. The results show that NPCMS greatly improves the heat transfer coefficient within the phase-change temperature range, especially the coefficient at the stagnation point of heated surface, but reduces the uniformity of heat transfer. The optimal heat transfer performance occurs when the initial temperature of NPCMS is 301 K, 0.9 K lower than the peak temperature of phase change. The heat transfer coefficient at the center of wall is almost twice of that of the water due to latent heat absorption. Lower surface tension and viscosity are beneficial to improving spray cooling performance.