工质热力性质与梯级蒸发有机朗肯循环能量耦合机理

The organic Rankine cycle (ORC) has been widely used in thermal energy conversion.The single-stage evaporation is a key factor that results in the irreversible loss in the evaporator.Due to the poor performance of the ORC, the cascade evaporating organic Rankine cycle (CEORC) is proposed.The theoretical analysis and numerical simulation are combined with the experimental test.The evaporating mode, hierarchical strategy,and energy coupling mechanism and grade interaction rule between the heat source and sink are discussed.The heat transfer processes in the evaporator and the condenser are focused on, which are coupled with the energy conversion processes in the turbine and the pump.Based on the temperatures of the heat source and the environmental condition,an optimization model of the system performance is established, which illuminates the interaction rules between the thermodynamic properties of the working fluid,the cold and heat sources, and the cycle processes of the CEORC.A series double evaporating organic Rankine cycle is established and experimentally tested.The interaction rules between the working fluid and system design parameters are quantitatively investigated.The temperature glide,the change mechanism of the ratio of the pure component in the non-azeotropic mixtures,the output characteristics under all working conditions are also illustrated while the the parameters of the cold and heat source varies or system leaks. the experimental test and the numerical simulation are mutually validates each other, which correctly understands the influence rules of the evaporating mode and the hierarchical strategy to the system performance of the CEORC.

有机朗肯循环技术在热能转换领域具有广泛的应用背景，工质单级蒸发是引起蒸发器不可逆损失的重要因素。针对传统有机朗肯循环性能较差的问题，提出梯级蒸发有机朗肯循环技术。本项目采用理论分析、数值模拟和实验研究相结合的方法，探讨工质蒸发模式及分级策略与冷热源之间的能量耦合机理和品位关联规律，着重研究蒸发器和冷凝器中的热量传递过程，并与汽轮机和工质泵中的能量转换过程耦合，构建基于热源温度和环境条件的系统整体性能优化模型，并阐明工质热力性质、冷热源参数与循环过程之间的相互作用规律。建立串联双级蒸发有机朗肯循环实验台，定量研究工质与系统设计参数之间的关联规律；阐明冷热源参数变化和系统泄漏时非共沸混合工质的温度滑移、组元配比变化机理以及系统全工况输出特性。通过实验与数值结果的相互验证，正确认识梯级蒸发模式和分级策略对有机朗肯循环发电性能的影响规律。

有机朗肯循环技术在热电转换领域具有广阔的应用前景，工质单级蒸发是引起蒸发器不可逆损失的重要因素之一。针对热源与工质之间匹配性较差的问题，本项目提出了梯级蒸发有机朗肯循环技术，采用了理论分析、数值模拟和实验研究相结合的方法，探讨工质蒸发模式及梯级蒸发策略与冷热源之间的能量耦合机理和品位关联规律，着重研究了蒸发器和冷凝器中的热量传递过程以及汽轮机和工质泵中的能量转换过程耦合，构建了基于热源温度和环境条件的系统整体性能优化模型，研究了工质热力性质、冷热源参数与循环过程之间的相互作用规律；设计并搭建了有机朗肯循环实验台，定量研究了冷热源参数变化、工质充注量与系统设计参数之间的动态特性，通过实验测试与数值结果的相互验证，揭示了梯级蒸发模式和分级策略对有机朗肯循环发电性能的影响。