超临界 CO2微细管内传热特性研究

摘要

Micro information of flow and heat transfer of supercritical carbon dioxide in miniature cooled tubes were investigated including the turbulent kinetic energy distribution in different sections of cooled tube,the dimensionless temperature and velocity distribution and turbulent Reynolds number distribution.The simulated data indicated that turbulence kinetic energy changement near the wall had a great influence on the heat transfer,buoyancy effects should be considered to heat transfer correlations in mini-ature tubes.Heat transfer characteristics of supercritical carbon dioxide in different diameter tubes of 0.5,0.3,0.1 mm were cal-culated and analyzed.Heat transfer correlations in cooled vertical miniature tubes the diameter less than 0.5 mm were obtained, which could be the efficient supplement for existing studies of heat transfer characteristics of supercritical CO2 .%考察超临界 CO2微细管内冷却条件下流动和换热的细观信息（管内不同截面湍动能分布，无量纲速度和温度分布以及湍流雷诺数分布等），结果表明：近壁处湍动能的变化对传热有较大影响，微细管内换热关联式需考虑浮升力的影响。对管径 d ＝0．5，0．3，0．1 mm 时，超临界 CO2的换热特性进行计算分析，回归出管径小于0．5 mm 时，超临界 CO2在冷却条件下竖直向上流动和竖直向下流动时的换热关联式，作为对超临界 CO2研究的有效补充。