Pool boiling heat transfer on vertical walls with staggered diamond-shaped ribs

Abstract Pool boiling experiments were conducted on vertical walls using deionized water as the working fluid under atmospheric pressure, comparing staggered diamond-shaped rib-structured surfaces with smooth surfaces. Through experimental measurements and visual analysis, the effects of surface structures on pool boiling performance were systematically investigated. The results demonstrate that the staggered arrangement of diamond-shaped ribs forms asymmetric bubble escape paths that leverage gravitational forces, enabling directional bubble ascent along rib grooves. This unique structure not only provides dense bubble nucleation sites through sharp edges but also effectively mitigates bubble blockage by avoiding interference from upper ribs during bubble departure. Compared to the smooth surface, the staggered diamond-shaped rib structure delays the onset of critical heat flux (CHF) by 30%. Furthermore, it increases the peak heat transfer coefficient by 70% in the moderate heat flux range. Meanwhile, the microchannels between ribs maintain efficient liquid-vapor exchange, significantly suppressing vapor film formation.