Effect of a Heat Flux Spike on the Downstream Dryout Behavior

D.C. Groeneveld

Journal of Heat Transfer · 1974 · 14 citations · 0 references

Concepts

Abstract

The effect of a short hot patch on the downstream dryout behavior was investigated in heated tubes cooled by Freon-12 at conditions equivalent (on the basis of liquid to vapor density ratio) to 69 bar in steam-water. The hot patch, located well upstream from the heated end, generated a heat flux spike which resulted in a local dry patch. Following an increase in downstream surface heat flux the dry patch would often spread in the downstream direction even though the heat flux was only a small fraction of the measured critical heat flux with uniform heating. A force balance on the dry patch boundary showed that, for certain conditions, spreading of the dry patch in the downstream direction is inevitable. This spreading however can be limited by interfacial instability, droplet-wall interaction and axial conduction.