Unified descriptor for enhanced critical heat flux during pool boiling of hemi-wicking surfaces

•Experimentally demonstrated that pool boiling CHF enhancement on hemi-wicking surfaces cannot be explained by roughness or wickability alone.•Experimental results of systematically designed micropillar surfaces showed that CHF depends on both roughness and wickability.•Performed a scaling analysis to derive a relationship for CHF with a unified descriptor associated with thin film density and volumetric wicking rate.•Thin film density and volumetric wicking rate enhance CHF by accelerating bubble departure frequency and delaying the dry-out at bubble base.•CHF values from our experiments and literature data showed a positive linear correlation with the unified descriptor.