Towards an Explanation of the Mechanism of Boiling Critical Heat Flux Enhancement in Nanofluids

Nanofluids exhibit a very significant enhancement of the boiling Critical Heat Flux (CHF) at low nanoparticle concentrations. This paper reviews the nanofluid boiling database in a quest for the CHF enhancement mechanism. Briefly, buildup of a nanoparticle layer on the heated surface occurs upon boiling of nanofluids. This layer changes the surface roughness and the nucleation site density and, remarkably, can improve the surface wettability, as shown by a reduction of the static contact angle on the nanofluid-boiled surfaces. Significant differences are also observed in the dynamic behavior of the hot spot at CHF.