摘要
本文对超临界压力CO2在垂直圆管(Din=2 mm)内在高进口雷诺数和低进口雷诺数条件下的对流换热进行了实验研究,以研究变物性、浮升力和热加速对流动和换热的影响.实验结果发现,在低进口雷诺数情况下,向上流动中管子入口处出现了局部壁面温度下降,而在向下流动中未观察到此类现象;在高进口雷诺数情况下,向上流动中壁面温度发生了异常分布,这主要是因为向上流动中浮升力使得湍流发生了层流化现象,而在向下流动中未观察到此类现象.
Convection heat transfer of CO2 at supercritical pressures in a vertical tube （Din=2 mm） was investigated experimentally in order to study the effects of the variation of physical properties, buoyancy and thermal acceleration on the convection heat transfer. For the case of low inlet Re number, the phenomenon of local wall temperature decrease was observed in upward flow which was not in downward flow. For the case of high inlet Re number, the local wall temperature showed an abnormal distribution due to the strong influence of buoyancy which result in the flow laminarization of the turbulence which was not observed in downward flow.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2008年第3期461-464,共4页
Journal of Engineering Thermophysics
基金
教育部科学技术重大项目(No．306001)
国家863计划项目(No．2006AA05Z416)
关键词
超临界压力
浮升力
热加速
层流化
supercritical pressures
buoyancy
thermal acceleration
laminarization
