含不凝性气体蒸汽凝结换热的壁面过冷度分析

Analysis on the wall sub-cooling of heat transfer of steam condensation with non-condensable air

针对核反应堆事故工况下的安全分析,通过含空气蒸汽在竖直圆管外表面的冷凝传热实验,在重点分析壁面过冷度的基础上,研究了空气质量分数、压力以及壁面过冷度同蒸汽冷凝换热的关系.结果表明:实验条件下,壁面过冷度同冷凝传热系数呈指数关系,指数项的值小于-0.39,相对Dehbi结果,其对传热的影响程度较为强烈;壁面过冷度对冷凝传热系数的影响随着压力的降低、空气质量分数的增加以及壁面过冷度的增加而增加,且得到了相应的关系式;基于对壁面过冷度的分析,进一步得到了压力、空气质量分数、壁面过冷度对冷凝传热系数影响的实验关联式.

For the purpose of conducting safety analysis on nuclear reactor accidents, experiments were done with heat transfer of steam condensation containing air on the outside surface of a vertical tube. The emphasis of the anal- ysis is concentrated on the wall sub-cooling. The research also includes the relationship of heat transfer of steam condensation with such parameters as air mass fraction, pressure, and wall sub-cooling. The results show that, un- der the experimental conditions, the relationship between wall sub-cooling and the coefficient of heat transfer of condensation （HTC） is exponential. The value of the exponent is less than -0.39, which is less than that of Dehbi＇s result and the influence on heat transfer found in this experiment is stronger. The influence of wall sub-cool- ing on HTC increases with the decrease in pressure, increasing of air mass fraction as well as the increase in wall sub-cooling, and the relationship curve is obtained. Based on the analysis of the wall sub-cooling, the experimental correlation between the influence of the air mass fraction, pressure, and wall sub-cooling on HTC is obtained.