Pool Boiling Heat Transfer Enhancement Using Bi-Conductive Surfaces

Abstract Due to its superior heat dissipation capability, pool boiling has been a research hotspot over the decades. This paper provides insights into the underlying pool boiling enhancement mechanism of bi-conductive surface which is an effective modification method. In this study, a new type of bi-conductive surface is created by embedding a reticular structure made of low-conductive epoxy into a high-conductive copper substrate. The influence of the width of epoxy is studied by conducting experiment as well as CFD simulation. Due to extreme differences in thermal conductivity, the heat flux almost exclusively flows throw copper. Moreover, epoxy inhibits nucleation because of its low surface energy. Bubbles are almost only generated on copper and the colder epoxy remains moist. The existence of epoxy creates periodic spatial surface temperature variations and induces separated liquid and vapor paths. As a result, compared with bare copper surface, bi-conductive surfaces have better heat transfer performance. For the bi-conductive surface with 0.75mm width of epoxy, replacing 44% of the high-conductive copper with low-conductive epoxy results in 270% increase in CHF value and 108% increase in the total effective thermal power at CHF.