超临界压力CO_(2)在非均匀加热竖直管内的换热特性研究  

Heat Transfer Performance of Supercritical Pressure CO_(2) in a Vertical Tube With Non-Uniform Heating

作　　者：刘晓凯 郭江峰[1,2] 韩增孝 张海燕 淮秀兰 LIU Xiaokai;GUO Jiangfeng;HAN Zengxiao;ZHANG Haiyan;HUAI Xiulan(Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China;School of Engineering Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院工程热物理研究所,北京100190 [2]中国科学院大学工程科学学院,北京100049

出　　处：《工程热物理学报》2022年第7期1951-1957,共7页Journal of Engineering Thermophysics

基　　金：国家重点研发计划课题(No.2017YFB0601803);国家能源集团重大先导项目(No.GJNY2030XDXM-19-10)。

摘　　要：基于工程中存在的非均匀热流问题,针对四种非均匀热流条件下超临界压力CO_(2)在竖直管内的流动换热特性进行了数值研究,分析了热流密度、质量流量、浮力效应和排布方式对流动换热性能以及圆管表面温度分布的影响。超临界压力CO_(2)在非均匀热流条件下表现更为复杂的流动换热特性,轴向热流密度分布不均匀会使传热恶化,增大热流密度和减小雷诺数可以弱化传热恶化效应;热流分布不均时,Bo^(∗)比Gr^(-)/Re^(2.7)更能准确地预测浮力效应;在非均匀热流条件下,竖直向下流动比竖直向上流动表现出更好的传热性能,径向速度和湍流动能分布可以较好地解释传热恶化的产生机理。本文对于光热、锅炉等非均匀热流条件下的工程应用具有一定的指导意义。The flow and heat transfer characteristics of supercritical pressure CO_(2) in a vertical tube under four non-uniform heat flux is numerically investigated.The effects of heat flux,mass flow rate,buoyancy effect and arrangement on the heat transfer performance and the temperature distribution on the tube are discussed.Under the condition of non-uniform heat flux,it shows more complex flow and heat transfer characteristics,the non-uniform axial heat flux distribution causes the heat transfer deterioration;and increasing heat flux and decreasing Reynolds number could weaken heat transfer deterioration.When the heat flux distribution is uneven,Bo^(∗)is better than Gr^(-)/Re^(2.7) to predict buoyancy effect and the temperature distribution on the tube shows great unevenness along the circumference and the axial direction.For the non-uniform condition,the heat transfer performance of vertical downward flow is better than that of upward flow.The heat transfer deterioration can be explained by the radial velocity and turbulent kinetic energy distribution.

关 键 词：超临界压力CO_(2) 对流换热 非均匀加热 浮力效应 数值模拟 

分 类 号：TK124[动力工程及工程热物理—工程热物理]