Boiling on a straight pin fin with an insulated or uninsulated tip

This paper investigated the heat transfer performance and associated stability characteristics of pin fin boiling with an insulated or uninsulated fin tip. Both linear stability analysis and experimental results reveals that, in both cases, (i) when film and transition boiling coexist on the fin surface, or only the transition boiling has covered the entire fin, the operation remains stable only if the fin length is less than some critical value; (ii) for transition + nucleate boiling, or the fin is in the three-mode boiling (film + transition + nucleate boiling), however, the boiling becomes stable. An uninsulated fin tip would enhance the stability of the boiling modes in (i), but to weaken it in (ii), with the magnitude controlled by a parameter σ_k. Experiments qualitatively verified the theoretical findings.