Effect of finned structure on Critical Heat Flux (CHF) in downward-face pool boiling

CHF plays an important role in the heat transfer process during the external reactor vessel cooling (IVR-ERVC) which is deemed as a very effective way to release the decay heat after the core melted. In this paper, the experiment of the macro-fin structure experiment positioned on slope that is declined at angles of 5° and 10° was done. The results of the copper bar experiment were then analyzed and compared with the results obtained from a copper block experiment that had been conducted previously at the same test facility, and it was found that the CHF decreased. Finally, the hot/dry spot theory for the copper bar was brought up in an attempt to explain the difference of copper and copper bar. It seemed that using this theory can explain the decrease of CHF for copper bar. (author)