熔融盐吸热器热性能的动态响应机理及非稳态测试方法研究

Molten salt receiver, which convert solar energy into thermal energy, is a key equipment in solar power tower plant. The dynamic characteristic of receiver is rather significant due to the continuous changing of weather condition such as solar irradiance. This project aims to study the dynamic characteristic of molten salt receiver under multi-variable (solar irradiance, ambient temperature, wind speed, inlet temperature, flow rate) induced unsteady condition. The coupling effect of solar and thermal energy on the receiver will be analyzed under quickly changing, highly intense and nonuniform energy flux distribution. The effective thermal capacity will be found by coupling the effect of fluid and solid parts. The heat transfer and energy loss characteristic during dynamic process will be studied. Then the theoretical derivation of key parameters will be conducted to represent the total heat loss and dynamic characteristic. Based on the expression from theoretical derivation, we will investigate the impact of key parameter on the thermal performance. Furthermore, the identification method for key parameters will be established which can applied to dynamic data. The dynamic model and identification method will be integrated into a complete unsteady test method for molten salt receiver. The model and effectiveness of identification method will be examined experimentally. The results of this project can promote the thermal performance evaluation, safe control and structure optimization for molten salt receiver.

熔融盐吸热器是太阳能塔式电站中承担光热转换的重要设备，由于太阳辐照等外界气象条件不断变化，使其具备超常的动态特性。本课题将开展多变量耦合（太阳辐照、环境温度、风速、入口温度、流量等）强动态工况下熔融盐吸热器热性能的动态响应机理研究，分析处于快速变化、高强度非均匀辐照场下的熔融盐吸热器光热耦合动态特性，构造能够反映吸热器流固多部件间耦合特性的有效热容项，研究强动态过程中吸热器传热及能量损失特性；理论推导可以表征吸热器总热损失和动态响应特性的特征参数表达式，从而揭示关键参数对熔融盐吸热器热性能的影响机理，进一步建立基于动态运行数据的热性能特征参数辨识方法；整合熔融盐吸热器动态模型及参数辨识方法建立完整的非稳态测试方法，实验验证理论模型的正确性以及参数辨识方法的有效性，为吸热器热性能的评估、安全控制和结构优化提供理论基础。

熔融盐吸热器是塔式热发电站中承担光热装换的核心设备，定日镜场的聚光特性和外界条件（辐照、风速、环温等）的变化导致吸热器长期处于非均匀能流分布及非稳态工况下运行，因此有必要掌握吸热器的热性能和动态特性以保证吸热器的安全运行；本项目针对熔融盐吸热器热性能的动态响应机理及非稳态测试方法展开了研究，取得了部分成果：（1）建立了经过实证的吸热器的光热耦合动态模型，可以在高强度非均匀能流密度下给出壁面及流体的温度场，并考察了常规运行方式对吸热器性能的影响，对比揭示了流量调控对吸热器有效输出能量的负面影响；（2）推导得到了表征吸热器热性能的热损失系数和效率因子以及表征吸热器动态特性的时间常数，并提出了符合塔式电站运行特性的吸热器热性能及动态特征参数的辨识方法，无需高温熔盐逆流；（3）基于吸热器光热耦合模型验证了热性能及动态特性参数的辨识方法，并对吸热器进行了非稳态过程的失效分析，可以基于温度场和应力场评估不同失效工况下吸热器的使用寿命。研究成果为熔融盐吸热器的结构设计和优化运行提供了重要的理论依据，并有助于形成吸热器动态特性的评价标准，规范吸热器的设计准则。本项目目前已经发表论文8篇，其中SCI、EI收录6篇，申请发明专利2项，培养博士研究生2名；