熔盐传热蓄热材料高温热力学与反应动力学机理研究

This project aims at the key scientific issues on optimization design and thermal stability mechanism analysis of high-temperature molten salts material in order to develop molten salts with low-cost and high-performance as thermal energy storage material and transfer fluid applied in heat storage technology. Unsteady deterioration problems caused by ionic polarization and microstructure parameters are investigated by experimental phenomenon and theoretical simulation in the process of high temperature heat transfer and thermal storage. Polarization theory of ions parameters and the law of eutectic point of molten salts are explored in order to predict phase diagram types of forming eutectic point. At the same time, thermal properties and phase equilibrium thermodynamic parameters of molten salts material are calculated in order to establish thermodynamic model of phase equilibrium of molten salts system and build high-temperature molten salts heat transfer-thermal storage material. Besides, thermodynamics and kinetics mechanism of molten salts deterioration problems in the unsteady process are analyzed. The relationship of thermal stability of molten salts material and microscopic reaction pathway is constructed. The optimization theory of high-temperature thermal stability of molten salts is revealed. In a word, the thermal stability mechanism and energy storing/releasing characteristics of molten salts material are explored and optimized in the process of material design from the molecular level in order to achieve the industrial applications of high temperature molten salts material and the development of heat storage technology.

本项目以发展高效蓄热技术为基础研究的工程背景，提炼出开发低成本高性能熔盐传热蓄热材料所需要解决的高温熔盐材料优化设计与构建理论、熔盐热稳定性测试与机理分析的关键科学问题作为研究目标。针对高温传热蓄热过程中熔盐材料离子极化、阴阳离子参数等微观因素所引起的熔盐流体高温非稳态劣化问题，进行深入的实验现象观察和理论模拟分析。探究熔盐中阴阳离子参数极化理论，揭示熔盐体系形成低共熔点的规律，预测熔盐材料形成低共熔点的相图类型。优化熔盐体系相平衡热力学参数，获取熔盐材料的热力学性质，建立熔盐体系相平衡热力学模型，构建高温熔盐传热蓄热材料体系。深入探悉熔盐材料非稳态劣化过程热力学规律与动力学机理，探讨熔盐体系高温热稳定性与材料微观反应路径的规律，构筑熔盐材料高温热稳定性优化机制。从分子水平设计低成本高性能熔盐材料，探索熔盐材料热稳定性机理，发展熔盐传热蓄热材料优化设计理论和制备方法。

本项目以发展高效蓄热技术为基础研究的工程背景，提炼出开发低成本高性能熔盐传热蓄热材料所需要解决的高温熔盐材料优化设计与构建理论、熔盐热稳定性测试与机理分析的关键科学问题作为研究目标。首先，利用支持向量机算法和能量最小化相图计算原理，结合热分析测试及可视化实验，经单纯形格子分析及最优化设计，预测未知熔盐体系的类型及共熔点，揭示未知熔盐体系形成共熔点规律，获取未知熔盐体系最佳初晶温度与组分配比关系，实现对低成本高性能熔融盐合成工艺的理论预测，为多元熔盐材料的配方设计提供理论指导。其次，采用第一性原理平面波赝势密度泛函理论及逆非平衡分子动力学计算方法，优化熔盐体系晶体结构，预测熔盐材料高温热力学性能参数，探究熔盐材料高温热力学性能优化机理，构建高温熔盐传热蓄热材料优化设计理论体系。最后，利用反应热力学与动力学相结合的方法，从微观和宏观两个层面上探悉熔盐材料高温非稳态劣化过程，探讨熔盐传热蓄热材料高温热稳定性的影响因素，揭示熔盐材料高温热稳定性的反应机理，预测熔盐材料最优操作温度范围，为熔盐材料实际应用提供理论指导与基础支撑。从分子水平拓展熔盐材料优化设计理论和制备方法，探索熔盐材料高温热稳定性机理，促进高温熔盐材料的工业应用和高效蓄热技术的发展。