基于热量流法的超临界CO2换热器性能分析

本文基于热量流法,应用进口温差定义的换热器通用热阻,采用分段法考虑超临界CO₂的物性变化,结合能量守恒方程,构建了超临界CO₂-冷却水换热过程的整体热量流拓扑模型,结合超临界CO₂物性库和经验关联式提出了换热器性能分析的流程图,实现了综合考虑物性-结构-运行参数的超临界CO₂-冷却水换热器的性能分析,进一步结合火积]耗散热阻的概念提出了评价物性变化时换热器换热性能的等效热阻。通过分析获得了换热量的沿程分布规律,发现当进口压力为11 MPa时,总的换热量最大,此时等效热阻最小。总之,热量流法对超临界CO₂为工质的换热器设计和系统分析是可行和有效的。

Performance Analysis of Supercritical CO Heat Exchanger Based on the Heat Current Method

Based on the heat current method,this paper introduces the general thermal resistance of the heat exchanger defined by the inlet temperature difference,considers the thermophysical variations of supercritical CO₂by the segmentation method,and combines the energy conservation equation to construct the overall heat current topology model of the supercritical CO₂-cooling water heat exchanger.Moreover,we propose the flow diagram of heat exchanger performance analysis combines the thermophysical properties of supercritical CO₂library and the empirical correlation equation and realize the performance analysis of supercritical CO₂-cooling water heat exchanger with integrated consideration of physical properties,structure,and operating parameters.Besides,the concept of entransy dissipation resistance is introduced for proposing the equivalent thermal resistance to evaluate the heat exchanger performance when physical properties change.These analysis results obtain the distribution of heat exchange along the flow direction and show that the total heat exchange is greatest,and the equivalent thermal resistance was lowest when the inlet pressure was 11 MPa.In all.the heat current method is feasible and effective for heat exchanger design and system analysis of supercritical CO₂.