Effects of Al2O3/R-123 nanofluids containing C19H40 core-shell phase change materials on critical heat flux

In this paper, the curiosity is coming from how to bring out the fluidic capability of nanofluids (fluid itself) for critical heat flux (CHF) enhancement away from surface deposition effects such as improved wettability. The pool boiling characteristics of dilute dispersions of alumina and the microencapsulated C19H40 phase change material (MPCM) in R-123 were studied. Whereas other nanofluid studies only reported that a significant enhancement of CHF was achieved by buildup of a porous layer of nanoparticles on the heater surface during nucleate boiling, it was found that the additional CHF enhancement of 24% occurred with the MPCM compared to alumina nanomaterials. With solid-liquid phase changes, PCMs in suspension delay the occurrence of CHF by absorbing heat around from the heater, nucleate bubbles and merged bubbles while PCM shells prevent leakage of molten cores and allows the return to solid with exchanges of heat at some distances. The present study found that PCMs could make fluidic effects of nanofluid not relying on the surface depositions.