(An) experimental investigation of condensation phenomena in a vertical U-tube with and without noncondensable cases

Abstract

Reflux condensation in steam generator tubes may be an important heat removal mechanism in a certain phase of small break loss of coolant accident in nuclear power plants. To predict the heat removal capability of steam generators when the heat transfer mode is a complete reflux condensation, experiments have been carried out with two inverted U-tube condenser. Since the effect of noncondensible gas to the condensation phenomena may beiimportant, the air as the noncondensible gas was used in the test. In addition, since the flow pattern in U-tube governs the heat removal capability, the flooding (the transition from countercurrent annular flow to churn or slug flow) phenomena of single and two tubes were investigated.