Study on Rewetting of High-Temperature Vertical-Narrow-Annular Flow Passages under Counter-Current Flow Condition

Abstract

Quenching of a thin-gap annular flow passage; δ=0.3∿5.0mm, by gravitational liquid penetration was examined experimentally by using R-113. The quenching was observed for the gap spacing over 1.0mm. When the spacing was less than 1.0mm, the wall was gradually and monotonously cooled down without any quenching. The peak heat flux during the quenching process was much lower than that in pool boiling and considerably decreased as the gap spacing became narrow. The surface area covered by liquid during the film boiling period decreased as the gap spacing became narrow, which corresponded well with the decrease of the peak heat flux with gap spacing decrease.