不同管径下超临界CO_(2)流动传热的数值分析  

Numerical analysis of the flow and heat transfer of supercritical CO_(2)under different tube diameters

作　　者：李超[1] 王宗一 廖敏 赵钦新[1] 邵怀爽 LI Chao;WANG Zongyi;LIAO Min;ZHAO Qinxin;SHAO Huaishuang(Key Laboratory of Thermal Fluid Science and Engineering,Xi′an Jiaotong University,Xi′an 710049,China)

机构地区：[1]西安交通大学热流科学与工程教育部重点实验室,陕西西安710049

出　　处：《哈尔滨工程大学学报》2022年第12期1778-1785,共8页Journal of Harbin Engineering University

基　　金：国家重点研发计划(2021YFC3001803);国家自然科学基金项目(52206114);中国博士后科学基金项目(2020TQ0239).

摘　　要：为了阐明加热工况下超临界CO_(2)复杂的传热恶化机理,本文通过数值模拟方法,结合场协同理论研究了管径对于超临界CO_(2)流动换热的影响,并分析了局部传热恶化的原因。在相同加热工况条件下,随着管道直径增大,浮升力效应增强,管道顶部积聚的低密度“类气”流体增多并加剧了局部传热恶化现象,这部分流体在管道顶部形成了新的涡流,通过努塞尔数的比值得出新涡流会使顶部传热恶化达20%。管径增大会使主涡流强度减弱,场协同角的分布更加不均匀。该研究工作可为超临界CO_(2)布雷顿循环应用于第4代核电站的研发设计工作提供理论指导。To clarify the complex heat transfer deterioration mechanism of supercritical CO_(2)under heating conditions,this study examines the influence of the tube diameter on the flow and heat transfer of supercritical CO_(2)through a numerical simulation method and field synergy theory and analyzes the causes of local heat transfer deterioration.Under the same heating condition,as the tube diameter increases,the buoyancy effect increases,and the low-density"gas-like"fluid accumulates at the top of the tube,which aggravates the local heat transfer deterioration phenomenon.This part of the fluid forms a new vortex at the top of the tube.In this paper,a conclusion is drawn from the ratio of the Nusselt number that the new vortex will worsen the heat transfer at the top by 20%.In addition,the increase in the tube diameter will weaken the main eddy current intensity and that the distribution of the field synergy angle is more uneven.The research results can provide theoretical guidance for the application of the supercritical CO_(2)Brayton cycle in the development and design of fourth-generation nuclear power plants.

关 键 词：超临界二氧化碳 水平管 数值模拟 传热恶化 二次流 浮升力 换热特性 场协同 

分 类 号：TK124[动力工程及工程热物理—工程热物理]