2상 자연순환 회로내 유동의 정적 불안정

Abstract

A simple, one-dimensional analytical model was introduced to describe the flow phenomena in a closed two-phase natural circulation loop. Homogeneous flow model was used for the two-phase region, and the time-averaged balance equation was derived. Effects of the sub-cooling and the valve friction resistances on the circulation rate were examined to find out the conditions of the flow instability. Flow becomes unstable with the increases of the sub-cooling and the friction resistance in the two-phase region or with the decrease of the friction resistance in the liquid region. Those trends were confirmed by a simpler model with the assumption of point-heat-source/sink, and the static (excursive) instability maps were also provided.