▎ 摘 要
In this work, reduced graphene oxide (rGO) is synthesized from graphite powder and various characterization techniques have been used to study the in-plane crystallite size, number of layers, presence of functional groups and surface morphology. The rGO flakes are dispersed in Millipore water to obtain 0.0005, 0.001, and 0.002 wt.% of rGO-water nanofluids. It is then used in the experimental facility to study the nucleate boiling heat transfer with different heating surfaces viz. smooth and sandblasted surface (SBS). Results of this study indicate (i) an enhancement in heat transfer coefficient (HTC) for concentration upto 0.001 wt.% and deterioration beyond this in the case of smooth surface, and (ii) an increase in HTC with concentrations is observed for SBS and shows a maximum enhancement of about 60% in comparison with smooth surface at 0.002 wt.%. It is found that the presence of secondary cavities (acts as nucleation sites) formed by the rGO flakes during boiling is responsible for the observed phenomena in addition to the possible effect of rGO in the fluid flow.