Boiling in Micro-Structures and Porous Media

Abstract

An experimental investigation was conducted to visually observe the boiling behavior in a 3D porous structure made of staggered glass beads, especially the bubble dynamics and pore-scale liquid flow around bubbles associated with the heat and mass transport at the bubble interface. The experiments show that the dynamic bubble behavior was significantly affected by the bead-packed structure, and several unique boiling phenomena caused by special pore geometry were observed and discussed. Intensive wetting of the liquid replenishment protected heated surface from full dryout. The bubble shape and primary bubble interface were described by using a force balance on the bubble. An introductory model was proposed to perform a theoretical analysis and explore the dryout process inside the pore structure. The theoretical results were compared with experimental data, and the present model provided a good explanation of the fundamental mechanisms and predicted the important influences of the bead-packed structure on dryout behavior.