可燃碳氢/阻燃剂非共沸混合工质与中高品位余热回收的多效协同机理

Organic Rankine cycle is a highly promising technology to recover medium and high grade waste heat. However, traditional organic working fluid is incapable of the “collaborative optimization of thermal performance, heat-transfer matching and system safety”, which means HCFC and HFC is unstable and environment-unfriendly while Hydrocarbon working fluid is well-adapted with high efficiency however flammable. Therefore this project proposes a concept of binary zeotropic mixtures containing hydrocarbon and retardant, with stable and safe properties, as well as excellent thermal performance and heat-transfer matching. Based on theoretical analysis and experimental research, this project consists of following sub-topics:①The research of thermodynamic performance matching mechanism between working mixtures and medium-to-high grade waste heat. ②The study on the explosive properties of working mixtures as well as the inhibition mechanism when recovering medium and high grade waste heat. ③Investigating the variation trend of the concentration in mixtures under large temperature difference, as well as its influence over heat matching during heat transfer process. ④Exploring the coupling rules of multiple parameters in waste heat recovery system, coordinating the characteristic of medium and high grade waste heat. Based on the researches above, the collaborative optimization theory of binary zeotropic mixtures containing hydrocarbon and retardant on thermodynamic performance optimization, explosion inhibition and heat-transfer matching strategy is obtained. This project, with important scientific significances as well as practical values, enriches and develops the theory of Organic Rankine Cycle for waste heat recovery.

有机朗肯循环在回收中高品位余热领域具有重要应用前景，但传统有机工质无法实现“热力性能、传热匹配和系统安全的协同优化”，即传统的氯氟烃类和氟化烃类稳定性和环境特性差，碳氢类稳定和性能优良，但可燃。为此，本项目提出可燃碳氢/阻燃剂的非共沸二元混合工质，发挥其稳定、安全、热力性能优良及非共沸工质热匹配性好的特点。基于理论分析和试验测试开展：①混合工质与中高品位余热回收的热力性能匹配机制研究；②中高品位热源条件下混合工质燃爆特性和抑制机理研究；③大温差梯度下混合工质组份迁移规律及对传热过程匹配影响机理研究；④与中高品位余热特性协调的余热回收系统多参数耦合规律研究。通过上述研究，最终实现“建立可燃碳氢/阻燃剂非共沸混合工质与中高品位余热回收在热力循环性能、工质燃爆抑制和换热最佳匹配的多效协同理论”的研究目标。本研究丰富和发展了余热回收有机朗肯循环理论，具有重要科学意义和实用价值。

针对中高品位余热回收，为了解决碳氢类工质无法实现“热力性能、传热匹配和系统安全的协同优化”的问题，本项目提出可燃碳氢/阻燃剂的非共沸二元混合工质，发挥其稳定、安全、热力性能优良及非共沸工质热匹配性好的特点。为此，从混合工质热力匹配方法、燃爆特性与系统安全评价、传热过程组份迁移与过程匹配、多参数特性实验与动态仿真等角度开展了深入研究。本项目按预定计划完成了项目制定的研究内容：1）基于提出的温度-热流量(t-q)图分析方法，完成了基于理想工质物性的混合工质循环设计，提出了实现最佳热力匹配的新型CO2混合工质方案；2）开展了混合工质燃爆特性与系统安全评价研究，实验测试获得了不同可燃碳氢/CO2混合工质的可燃极限数据，提出可燃工质燃爆特性预测理论，并构建系统安全评价体系；3）获得了混合工质在大温度梯度传热过程中的组份迁移规律，以此建立了组份迁移与工质物性之间的联系，并获得了组份迁移对热力循环性能的影响机制；4）基于以上方法，自主设计并研制混合工质循环实验样机，开展了非共沸混合工质传热匹配、循环性能及系统运行之间多参数匹配实验研究，并获得高精度动态仿真模型。基于本项目提出的混合工质循环技术，与玉柴、宇通开展了相关的技术应用开发项目。所开发混合工质ORC余热回收系统，最大输出功率为7.51kW，实现混合动力专用发动机有效热效率提升3.13%。通过本项目的开展，共发表SCI论文17篇，EI论文7篇，SCI他引192次，1篇入选ESI高被引论文；申请发明专利23项，授权3项，授权软件著作权1项；合作出版中英文专著2部；受邀为PECS（IF=28.938）撰写综述论文；在国内外学术会议做大会/分会邀请报告10次。共计培养博硕士研究生12名，包括中国汽车工程学会和内燃机学会优博各1名。2020年以第二完成人获国家自然科学二等奖、获国家优秀青年基金资助，获教育部霍英东高等院校青年教师奖。