High mass flux flow boiling and critical heat flux in microscale

This study explores critical heat flux in flow boiling of de-ionized water at high mass fluxes in ~249 µm and ~494 µm inner diameter tubes, which are heated along short heated lengths (2-10 mm). Ultra high heat flux cooling (>10000 W/cm2) is achieved in micro scale at high mass fluxes (>10000 kg/m2s). Input heating powers were measured and processed to obtain critical heat fluxes (CHF). It was shown that high heat removal rates more than 30000 W/cm2 were attained with a reasonable combination of working conditions (short heated length-high mass flux-small hydraulic diameter), which can be proposed as a promising solution method for possible new emerging applications such as nano-scale plasmonic applications, near field radiative energy exchange between objects, and nano thermophotovoltaics. Experimental results were compared with the existing CHF prediction methods recommended for low quality flow boiling, and a new correlation for predicting CHF was proposed.