Numerical investigation of bubble dynamics and boiling heat transfer in porous structures via phase-change lattice Boltzmann method

Porous structure has been proven as a promising technique to enhance pool boiling heat transfer for high-heat-flux thermal management. In this study, a two-dimensional pseudopotential thermal lattice Boltzmann method is employed to numerically investigate the pool boiling characteristics and bubble dynamics within porous media. To overcome the two-dimensional truncation defects of porous structures, a “virtual thermal bridge” is introduced to reconstruct the connectivity between the solid matrix. The effects of porosity and surface wettability are then systematically analyzed. Results indicate that, compared with a plain heating surface, the introduction of the porous matrix significantly enhances boiling heat transfer performance and alter the bubble dynamics. Within the porosity range of 69.99% to 96.7%, the critical heat flux increases by an average of 1.5 times, reaching a maximum of 2.02 times. Notably, the heat transfer performance exhibits a non-monotonic dependency on porosity, peaking at 77.46%. This reveals a competitive mechanism between the augmented heat transfer area and the increased bubble escape resistance. Furthermore, stronger surface hydrophilicity accelerates bubble departure, yielding superior performance. These findings elucidate the regulatory role of porous parameters, providing theoretical guidance for optimizing porous structures to further enhance boiling heat transfer.