Boiling of highly wetting liquids in oscillatory flow

Abstract

In the present study, boiling of highly wetting dielectric fluid has been investigated in an oscillating Fluid environment. A piston is designed to create oscillations in the fluid and over a heated platinum wire. Because of their low surface tension, these liquids require very high superheat to initiate nucleate boiling. It is expected that the amount of necessary temperature overshoot for the onset of nucleate boiling, can be decreased with oscillation in the fluid. The oscillation can remove the bubbles, which are forming in the nucleation sites as soon as they start growing on the outer surface. This increases efficiency of nucleation sites, which are very scarce. All of the oscillation amplitudes and frequencies, tested here, changed the boiling curve of highly wetting dielectric fluid, so that the apparent temperature overshoot has decreased. Remarkably at some oscillation amplitude and frequencies the superheat is almost vanished. The effects of the amplitudes and frequencies on the boiling curve varied because of the present bubble size and growth rate, which depend on the size and shape of the nucleation sites. (AN)