HFO+HFC工质体系液相比热容声子与平均场理论研究

氢氟烯烃和氢氟烃混合工质将纯质进行优势互补，兼具良好的环保、安全、热工和循环性能，受到了广泛关注。工质的比热容数据对换热器设计、循环优化等具有重要的影响。但目前针对氢氟烯烃和氢氟烃工质体系液相比热容的实验研究数据缺乏、温度范围窄，理论模型微观机理、构效关系尚不明晰。因此,本项目将系统开展氢氟烯烃和氢氟烃工质体系液相(远临界液相区及近临界液相区)比热容研究,包括改进稳态流动量热实验系统，获取目标工质体系比热容基础数据，阐明目标工质体系液相比热容对温度/压力/组分的依存性；基于声子理论，构建远临界液相区目标工质体系“声子运动-组分配比-比热容性质”普适性映射关系模型；借助平均场理论，结合实验数据，揭示目标工质体系在近临界液相区的奇异变化规律。本项目的实施，将进一步拓宽声子理论的应用范围，有助于比热容理论的发展和完善，为氢氟烯烃和氢氟烃混合工质的科学研究和工程应用提供必要的理论依据和实验基础。

HFO (hydrofluoroolefin)+HFC (hydrofluorocarbon) mixtures gained the advantages of pure components and had environmental-friendly, nonflammable, reliable thermal and cycle performance. So the mixture system has received extensive attention. Furthermore, the isobaric heat capacity of fluids is of importance for heat exchanger design and cycle optimization. However, the experimental data of the heat capacity for the HFO+HFC systems are scarce and the experimental temperature range is limited. In addition, the microcosmic mechanism and structure-activity relationship are still unclear. Therefore, the project is aimed to study heat capacities of HFO+HFC systems in liquid phase (including the compressed liquid phase region and near critical region). The contents are as follows: To improve the steady flow calorimeter and obtain experimental heat capacity data for HFO+HFC systems in order to investigate the dependence of the liquid heat capacity on temperature/pressure/composition; To construct the mapping relationship "phonon motion-composition- heat capacity " of the target systems in the compressed liquid region on the basis of the phonon theory; To reveal the pattern of the target system in the near critical liquid region by using mean field theory. This project will broaden the application of phonon theory. Moreover, this project will help the improvement of the heat capacity theory. The study has important theoretical significance and practical value of engineering of HFO+HFC systems.