非均匀变辐射能流分布条件下光热动态耦合过程中的抛物面槽式太阳能集热器热性能机理与实验研究

The in-depth study on the thermal performance mechanism of parabolic trough solar collector (PTC) with running under random variations of the time and space is very significant. In this project, mathematical and physical models, as well as their solution methods, of the coupled radiation-conduction-convection and multi-process heat transfer among the PTC, components and heat transfer fluid (HTF) in the non-uniform and variant distribution of the radiation flux will be develop to calculate temperature fields of the heat collection element (HCE) and HTF with the experimental verification in order to provide the scientific theory for the thermal performance calculation and construction design of the PTC; by using both methods of experimental study and numerical simulation, the optical and thermal response mechanism of the PTC to complex conditions including the nonuniform, strongly variant solar irradiance and instantaneously changing inlet temperature and flowrate of HTF will be uncovered to benefit the safety monitor for operational systems; and through on-site tests, wind tunnel experiments and theoretical analysis, the research on the mechanisms of the thermal loss caused by the wind speed and direction and the optical loss caused by the reflector distortion and distant HCE position will be carried out to determine the accurately quantitative correlation between the thermal performance and inner loss of the PTC as well as the relationship between the collector and inner component efficiency, which provides the theoretical foundation for relevant national standards.

深入研究处于时空分布随机变化条件下运行的抛物面槽式太阳能集热器热性能机理具有重要意义。本项目开展在非均匀且变化辐射能流分布条件下槽式集热器整体、各部件间以及管内传热工质的多过程辐射-导热-对流耦合换热的数学物理模型及求解方法研究，准确计算吸热管及管内传热工质的温度场并进行实验验证，为槽式集热器的动态热性能计算和结构设计提供科学理论；运用实验研究和数值模拟相结合的方法，揭示在非均匀、急剧变化的太阳能辐射和传热工质的进口温度及流量突变等条件下槽式集热器的光热响应机理，以解决运行系统的安全监测问题；综合运用现场实测、风洞实验及理论分析等方法，探索风速风向造成的热损失机理和抛物面槽式聚光器形变及吸热管偏置造成的光损失机理，系统全面开展热性能与内部损失之间的明确数量关联关系以及集热效率与内部效率的变化规律研究，为建立相关国家标准提供理论依据。

抛物面槽式太阳能集热器及发电系统在我国正得到发展和重视，本项目所研究的内容为这项技术的发展提供了软环境支撑。本项目通过研究处于时空分布随机变化条件下运行的抛物面槽式太阳能集热器光热性能机理，建立了基于椎体光学法和蒙特卡洛光线追迹法相结合的槽式集热器非均匀且变化辐射能流分布模型、吸热管内多过程辐射-导热-对流耦合动态换热模型、以及抛物面槽式太阳能集热器动态聚光-集热性能模型。基于建立的槽式集热器性能测试双轴跟踪旋转实验测量平台和规模化槽式集热器实验测量平台，开展了一系列的实验研究，对项目形成的理论方法进行了实验验证。通过分析槽式集热器在非均匀以及剧烈变化辐射能流分布条件下的动态热性能产生机理和光热损失机理，明确了槽式集热器热性能与内部损失之间的数量关联关系和对各关键影响光热性能因素的响应变化规律研究，为规模化抛物面槽式太阳能集热器的设计、控制操作和运行安全提供了理论依据。此外，在这些研究的基础上形成抛物面槽式太阳能集热器热性能动态评价方法，编制了的标准《抛物面槽式太阳能集热器热性能动态测试方法》成为了国家太阳能光热产业技术创新战略联盟的标准，填补了国内相关标准的空白，也为太阳能热发电领域的发展做出了贡献。