Critical height of micro/nano structures for pool boiling heat transfer enhancement

Critical heat flux (CHF) enhancement by surface modifications has been an extensively researched area in pool boiling heat transfer. Here we report a fundamental mechanism of CHF enhancement where nano/micro ridges are fabricated on surfaces to fragment and evaporate the metastable non-evaporating/adsorbed film present at the base of a bubble in the contact line region. CHF increase of similar to 125% is obtained with only similar to 40% increase in surface area. An analytical model is extended to explain the CHF enhancement and to determine the average non-evaporating film thickness, which serves as the critical height for nano/micro structures for pool boiling heat transfer enhancement. (C) 2013 AIP Publishing LLC.