Monotonic CHF increase with enhanced wicked liquid volume rate on nanostructured surfaces

It has been found that wicking potential on nanostructures can enhance the CHF. Rahman et al. reported that the CHF enhancement depends strongly on the wicked liquid volume rate, called wickability, by measuring the absorbed liquid rate in a capillary tube. Here, the wicked liquid volume rate needs to be separately investigated in light of the pore cross-sectional area and the wicking velocity because the particle size of nanostructures differently affects those parameters. Finally, the wicked liquid volume rate, combination of the pore cross-sectional area and the wicking velocity, showed linear relation with CHF enhancement. Pool boiling experiments were conducted with grade 304 stainless steel samples sputtered by Cr at substrate temperature of 150.deg.C, 300.deg.C, and 600.deg.C before and after oxidation at 400.deg.C during 20 days. In this study, the effect of the wicked liquid volume rate, which is the product of the square average particle diameter and the spreading velocity, on enhancement in CHF was analyzed according to the microlayer evaporation mechanism.