Influence of porous structure on bubble dynamics and boiling heat transfer characteristics on the vertically heating surface via LBM approach

Boiling heat transfer characteristics greatly depend on bubble dynamics. The confined space formed by porous structures affects the micro-liquid layer distribution and coalescence fragmentation behaviors of bubbles. In this study, the effect of porous structures on bubble dynamics and boiling heat transfer characteristics on the vertically rough heating wall is numerically investigated based on a hybrid lattice Boltzmann method. The relationship between bubble dynamics and boiling heat transfer characteristics is obtained. The coupling mechanism of heat transfer enhancement by porous structure and wettability is revealed. The results indicate that the addition of porous structure significantly alters bubble dynamics, weakens the interaction between bubbles and compresses the micro-liquid layer space, leading to the local dryout phenomenon. There is a higher convective heat transfer intensity using the step wettability scheme.