Effect of CVD grown graphene monolayer thermal effusivity on phase change heat transfer in 2-D plate condition with highly wettable FC-72

Boiling is the most efficient heat-transfer method because of the large enthalpy difference between the liquid and vapor phases of the working fluid. Several studies have been performed to enhance both the boiling heat transfer (BHT) and the critical heat flux (CHF) in pool boiling with heater surface with enhanced heater thermal properties. Since the discovery of the 2-D carbon allotrope called graphene, several studies have been conducted on boiling applications, and enhanced boiling performance for both BHT and CHF has been reported. The main contributor to the enhanced boiling performance was observed to be the superior thermal properties of graphene, especially its thermal effusivity. However, compared with the role of other enhancement parameters such as surface wettability and capillarity on boiling heat-transfer performance, the role of the thermal properties of a material is not very clearly understood. The understanding and precise prediction of boiling performance are critical for the thermal design of various thermal fluidic devices. Therefore, in this study, saturated pool boiling was performed to investigate the underlying physics regarding the effects of material thermal properties on boiling heat transfer, using a chemical vapor deposition (CVD)-grown graphene sheet on a sapphire and silicon-based heater surface. A temperature-field-visualization study was conducted to analyze the spatiotemporal change in the temperature field caused by the changes in the material thermal properties, owing to the deposition of the graphene sheet.