窄缝通道内过冷沸腾区域汽泡脱离频率研究

采用高速摄像仪对矩形窄缝通道内垂直上升流过冷流动沸腾区域汽泡脱离频率进行可视化实验研究。结果表明,汽泡脱离频率随质量流速的增大而减小,随入口过冷度的增大而减小,随热流密度的增大而增大。将实验数据与文献中汽泡脱离频率计算模型进行比较,发现基于池式沸腾和饱和流动沸腾开发的计算模型不能准确预测过冷沸腾区域汽泡脱离频率。本文以无量纲参数的形式,分别用液相雷诺数、过冷雅各布数和核态沸腾热流密度表示质量流速、主流过冷度和热流密度对汽泡脱离频率的影响,获得矩形窄缝通道内过冷沸腾区域汽泡脱离频率预测关系式,关系式的平均预测误差为±17.1%。

Study on Bubble Departure Frequency in Subcooled Boiling Flow under Narrow Rectangular Channel

A visual study on forced convection subcooled water boiling experiments was conducted in vertical upward narrow rectangular channels by using the high-speed digital video camera.The results show that the increasing of mass flux or subcooled inlet causes the decreasing of bubble frequency,and the increas-ing of the heat flux causes the increasing of bubble frequency.Existing models were compared with the ex-perimental data of bubble frequency.The correlations developed for the pool boiling or saturated boiling do not work well for subcooled boiling flow.A dimensionless bubble departure frequency correlation has been sought for the influence of mass flux,subcooled flow and heat flux by using the dimensionless number of Reynolds number,Jacob number and dimensionless nucleate boiling heat flux.The proposed model agreed with the experimental data within the averaged relative deviation of ±17.1%.