Numerical investigation on the influence of porous media structural parameters on pool boiling heat transfer performance

Abstract

This work investigates pool boiling heat transfer (BHT) and bubble dynamics from a porous medium. The influence of the porous media structural parameters, such as porosity, pore density, porous medium height, thermal conductivity, and wettability, are mainly investigated. The findings indicate that the presence of porous media can increase the critical heat flux (CHF) by an average of 3.75 times and the BHT coefficient by an average of 3.84 times when porosity varies between 57.5% and 98.0% as compared to the plain surface. It is also found that both the CHF and BHT coefficient increase as the porosity decreases if porosity ε≥71.4%. However, they drop with the porosity decreases if porosity ε≤71.4%. On the other hand, the number of nucleation sites, heat transfer area, and bubble escape resistance increase as pore density increases. In addition, increasing the porous media height may enhance BHT performance, but too high a porous media increases the bubble escape resistance and restricts the separation of bubbles. Moreover, the CHF value and the maximum BHT coefficient increase with the thermal conductivity of porous media linearly. Finally, the stronger the wettability, the faster the bubble detachment, and the stronger the BHT performance.