摘要
采用SSTk-ω模型对冷却条件下超临界压力CO_2在水平管内的对流换热进行了数值研究,分析了流体物性、热流密度、直径以及浮升力等对其在拟临界点附近的流动换热特性的影响,并从场协同的角度分析了超临界压力CO_2的传热机理。结果表明:浮力效应使流体在流动截面上出现温度场不对称和二次流现象;下壁面的对流换热系数比上壁面先达到峰值,但换热系数小于上壁面;增大热流密度对换热系数的影响较小但能够使换热系数的峰值向入口段移动;增大热流密度和增大直径能够增强浮力效应对流体换热特性的影响;场协同原理可以解释同一截面处的换热不均匀现象。
The convective heat transfer of supercritical pressure CO2 in horizontal tube under cooling condition is numerically investigated using SST k-ωturbulent model. The effects of thermal physical properties, heat flux, tube diameter and buoyancy on the heat transfer characteristics are discussed. The results show that the temperature is asymmetric and secondary flow is generated on the cross section due to the buoyancy effect. The peak value of heat transfer coefficient appears earlier on the bottom surface than on the top surface, but its value is smaller than that on the top surface. The increasing heat flux has little influence on the peak value of heat transfer coefficient, but affects its position seriously. The larger the heat flux and the tube diameter are, the more significant the buoyancy effect is. The non-uniformity of heat transfer on the same cross section can be explained by field synergy principle.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2017年第9期1929-1934,共6页
Journal of Engineering Thermophysics
基金
国家重点研发计划项目(No.2016YFB0601701)
关键词
超临界压力CO2
对流换热
场协同原理
浮力效应
数值模拟
supercritical pressure CO2
convective heat transfer
field synergy principle
buoyancyeffect
numerical simulation
