超临界压力下填充床内气体流动及储热/储冷机理研究

Heat and cold thermal storage at supercritical pressure is the key link of the advanced air energy storage system, to understand and master the flow and heat transfer rules during the Heat and cold thermal storage progress is one of the prerequisites to ensure its safe and efficient operation. At the pressure of supercritical, fluid properties change acutely,especially near the pseudo-critical temperature,for which the heat transfer mechanism is very different atmospheric conditions, and the knowledge of the mechanism of flow and heat transfer through the packed beds is almost a blank. In this project, different status of the experimental study will be carried out to explore the influence of the pressure, flow, charge/discharge temperature, number of cycles, thermal properties of the particles, particle diameter and porosity on the flow, heat/cold thermal storage characteristics and the key heat transfer parameters.By the combination of theoretical analysis and numerical simulation based on pore scale, the coupling mechanism between singular change of the physical properties with the complex flow channel of the packed beds will be find out and the relations of the key transfer parameters of supercritical fluid flowing through packed beds will also be developed. The macroeconomic model to simulate the supercritical packed beds heat/cold thermal storage progress will be built which provides a theoretical basis and technical support for the design and optimization of supercritical packed bed heat/cold thermal storage device.

超临界压力下的储热与储冷是先进空气储能系统的关键环节，了解并掌握储热储冷过程的流动换热规律是保证其安全高效运行的前提之一。在超临界压力下，流体物性随温度变化剧烈，特别是在拟临界点温度附近，其传热机理较常压条件有很大区别，尤其是对填充床内流动换热机理的认识存在严重不足。本课题拟通过开展不同工况的实验研究，探寻压力、流量、储/释能温度、循环次数、颗粒热物性、颗粒直径和孔隙率等参数对超临界填充床流动、储热/储冷特性和关键传热参数的影响规律。结合实验结果、理论分析和基于孔隙尺度的数值模拟，揭示超临界工质热物性奇异变化与填充床复杂流道对界面传递现象的耦合作用机制，发展超临界压力下填充床的传热参数关联式。建立超临界压力下填充床储热/储冷过程的宏观预测模型，为超临界填充床储热/储冷装置的设计与优化提供理论依据和技术支撑。

超临界压力下的储热与储冷是先进空气储能系统的关键环节，了解并掌握储热储冷过程的流动换热规律是保证其安全高效运行的前提之一。在超临界压力下，流体物性随温度变化剧烈，特别是在拟临界点温度附近，其传热机理较常压条件有很大区别，尤其是对填充床内流动换热机理的认识存在不足。为揭示超临界条件下的填充床储热、储冷与相间换热特性与机理，本项目建立了高压填充床储热/储冷实验系统，完成了低压至超临界状态的填充床流动、储冷/储热实验研究，揭示了不同压力、储/释热温度、流量等参数对填充床储热储冷特性的影响，分析了各参数对储热储冷的影响机制；建立了流体-颗粒相间传热系数测量方法，完成了超临界流体-颗粒相间传热系数的实验测量，获得超临界压力下填充床的传热参数关联式；构建了三维单一颗粒与填充床颗粒堆积的物理模型，完成了在Aiding flow 和Opposing flow等不同工况下的单一颗粒与填充床混合对流换热过程进行了数值模拟，获得了填充床内流体/颗粒相间传热与储热/冷特性的影响规律；设计和制造了10GJ级大容量的新型高压填充床储冷装置，完成了大容量填充床储冷装置储冷性能实验研究。本项目的研究为超临界填充床储热/储冷装置的设计与优化提供了理论依据和技术支撑。