Numerical and experimental study of pool boiling heat transfer mechanisms in V-shaped grooved porous metals

Abstract

In this study, pool boiling heat transfer mechanisms in V-shaped grooved porous metals are studied using our porous metal model. The model eliminates the small Biot number restriction of linear temperature-distribution assumption and thus extends to large Biot number conditions, such as boiling heat transfer of porous metals relating multi-bubble agitation and coalescence. The effects of groove number, groove distance and groove width on pool boiling heat transfer are investigated using lattice Boltzmann method. The experimental study is also conducted to reveal bubble escaping paths. The results show that bubble departure frequency on the porous metal with double V-shaped grooves is higher than those on the porous metal with single V-shaped groove and the uniform porous metal. The experimental result indicates that the venting bubbles in lateral grooves are entrained by the central departure bubbles, which validate the numerical results. At the low heat fluxes, the wall superheat increases with increasing groove distance. The lotus-shaped bubbles form in the central porous metal. The bubble escaping resistance reduction leads to the heat transfer performance enhancement for the porous metal with the wide V-shaped grooves.