Pool boiling heat transfer characteristics of porous nickel microstructure surfaces

Abstract

Pool boiling as a mechanism for effective heat dissipation in battery thermal management systems can considerably mitigate this risk. In this study, we electrochemically deposited one smooth nickel specimen and three specimens with a porous nickel-stacked structure. The four samples underwent microstructural characterization via scanning electron microscopy. Through visual experiments, we evaluated their wettability, and through pool boiling experiments, we tested their boiling heat transfer properties. Our findings suggest that samples incorporating a porous nickel structure consistently outperform unmodified samples regarding heat transfer efficiency. Specifically, samples with a current density of 0.5 A·cm-2 demonstrated the most optimal boiling heat transfer performance, evidenced by a 65.6% reduction in temperature at the onset of boiling, a 16.1% increase in critical heat flux density, and a 160.7% larger maximum heat transfer coefficient compared to the smooth nickel sample. The superior performance of samples with porous nickel structures can be attributed to the availability of a more significant number of nucleation sites. Additionally, specimens with a current density of 0.5 A·cm-2 displayed smaller micro-crystalline dendritic structures, an attribute that further favorably influenced their boiling heat transfer performance.