摘要
为了弄清在窄缝环形流道中气泡的形成、聚合和变形的特性 ,以及气泡在聚合变形之后对传热特性的影响 ,在常压下用蒸馏水对窄缝间隙为 0 75mm的垂直环形流道 ,进行了可视化的流动沸腾传热实验研究 ;实验段的有效加热长度为 90 0mm ,其加热方式为单面内侧加热 ,实验的流量变化范围为 1 667× 1 0 - 5m3/s至 5 833× 1 0 - 5m3/s。实验得到了在不同质量流密度和热流密度下窄缝流道中的沸腾传热系数随干度变化的分布。通过与常规流道中的沸腾传热系数的比较 ,得到了在窄缝环形流道中沸腾传热系数比常规流道中的沸腾传热系数约高 1 5 %的结论。另外通过用高速摄像机对可视化的垂直环形流道中的流型进行的拍摄研究 。
To make clear the characteristics of bubble formation, coalescence and deformation in the narrow annular channel, a visible flow boiling heat transfer experiment has been carried out in vertical narrow annuli with inner side heating. Experiments are performed with distilled water at 1 atm or so for annuli with heating section of 900 mm and gap widths of 0.75 mm. The flow rates range from 1.667 ×10 -5 to 5.833×10 -5 m 3/s. Through the experiment, the profiles of the boiling heat transfer coefficient changing with dryness fraction at different mass flux and different heat flux have been obtained. It has been concluded that boiling heat transfer coefficient in narrow annular channel is 15 % higher than in conventional channel by comparison. Four boiling regimes in narrow annular channel are identified through high speed video camera.
出处
《核科学与工程》
CSCD
北大核心
2001年第3期244-251,共8页
Nuclear Science and Engineering
关键词
窄缝流道
气泡聚合变形
流型
流动沸腾传热
传热强化
核反应堆
热工水力学
narrow channel
bubble coalescence and deformation
flow pattern
flow boiling heat transfer
heat transfer enhancement
