超临界CO_2流体及其换热特性分析

Analysis of Supercritical CO_2 Fluid and the Heat Transfer Performance

对超临界CO2流体的换热处理原则、换热特点以及换热机理进行了分析,超临界CO2流体特殊的物性变化使得其传热与常规流体不同,应该按"变物性"来处理。通过物性分析比较,与常规工质的凝结换热性能进行了对比研究,超临界CO2具有良好的传热和流动特性,超临界CO2冷却过程换热与凝结换热性能相当。进而分析不凝性气体对超临界CO2的性质及换热性能的影响,其物性值会有所减小,换热性能也有所降低。

The heat transfer treatment principle, heat transfer characteristics and heat transfer mechanism of supercritical CO2 fluid are analyzed. The special change trend for the properties of supereritical CO2 fluid makes its heat transfer different from the traditional fluids. Thus the changeable thermo-physical properties should be adopted in the calculation equations. By properties comparison with the traditional refrigerants, the cooling heat transfer performance of supercritieal CO2 fluid is compared with the condensation heat transfer of the traditional refrigerants. The results show that their heat transfer performance is comparative due to the good heat transfer and flowing characteristics for supercritical CO2 fluid. In addition, the effect of non-condensation gas on the properties and heat transfer performance of supercritical CO2 fluid is analyzed. Both the properties values and heat transfer performance are reduced.