水平螺旋管内超临界CO_2冷却换热的数值模拟  

Numerical study of cooling heat transfer of supercritical carbon dioxide in a horizontal helically coiled tube

作　　者：徐肖肖[1] 吴杨杨[1] 刘朝[1] 王开正[1] 叶建[1] 

机构地区：[1]低品位能源利用技术及系统教育部重点实验室,重庆大学动力工程学院,重庆400030

出　　处：《物理学报》2015年第5期250-256,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51206197);中央高校基本科研业务费专项资金(批准号:CDJZR12140032);重庆市自然科学基金(批准号:CSTC2011BB6094)资助的课题~~

摘　　要：采用RNG k-ε湍流模型对超临界CO2流体在内径为4 mm,长度2000 mm,节距为10 mm,曲率为0.1的水平螺旋管内的冷却换热进行了数值模拟.研究了质量流量、热流量以及压力对换热系数的影响,并和超临界CO2在水平直管内的冷却换热进行了对比.研究结果表明,超临界CO2在水平螺旋管内流动产生的二次流强于水平直管内的二次流,前者的换热系数大于后者;换热系数随质量流量的增加而增大;在似气体区,换热系数随着热流量的增加而增大,而在似液体区,热流量对换热系数几乎没有影响;换热系数峰值点随着压力的升高而下降,并向高温区偏移.In the present study, cooling heat transfer of supercritical CO2 in a horizontal helically coiled-tube 4 mm in diameter, 2000 mm in length, a pitch of 10 mm and 0.1 in curvature is numerically investigated with RNG turbulence model. Influences of mass flow rate, heat flux and pressure on heat transfer of supercritical CO2 are studied. The characteristics of the flow and heat transfer are compared with those in a horizontal straight tube. Results show that the secondary flow and heat transfer coefficient in a helically coiled tube is obviously larger than in a horizontal straight tube. The heat transfer coefficient of supercritical CO2 increases with increasing mass flow rate, and the heat transfer coefficient increases slightly as the heat flux increases in the gas-like region, while the heat transfer coefficient is unaffected by heat flux in the liquid-like region. The peak of the heat transfer coefficient decreases and shifts to a higher temperature region as the pressure increases.

关 键 词：超临界二氧化碳 数值模拟 螺旋管 冷却换热 

分 类 号：TK124[动力工程及工程热物理—工程热物理]