Overcoming the Heat Transfer Paradox: Nano Ridges Induce "Pistol Bubbles" and Reverse the Boiling Curve.

Abstract

To increase the boiling heat transfer limit, we disrupted the previously nonevaporating region and increased the vaporization activity of "inert" liquid molecules by introducing nano ridges on the boiling surface. This solved the paradox of no heat transfer occurring through the thinnest liquid film in boiling bubbles; thus, the internal heat transfer limit of the bubbles was exceeded. We found that vigorous boiling occurred immediately once the nonevaporating region was activated, and the bubble frequency increased by an order of magnitude, reaching 1186 Hz, which has not been previously reported. With an increase in heat flux, the boiling curve exhibited a "return". We achieved an extremely high bubble frequency by experimentally quantifying the major influence of nonevaporating region disruption on boiling heat transfer. The mechanism behind the generation of the ultrahigh-frequency bubbles was discovered. This study also reveals a new mechanism for the reversed boiling curve.