物性畸变诱导条件下超临界流体边界层结构及传热恶化机理研究

Supercritical carbon dioxide Brayton cycle system and supercritical water-cooled reactor are new nuclear energy power systems with supercritical fluid as working fluid. The former is considered as an alternative to the current large-scale use of steam power plants and the innovation of power technology. While, the latter is the only water-cooled reactor among the six highly promising nuclear energy systems identified by the Generation Four International Forum on Nuclear Energy Systems (GIF), representing the future direction of the current water reactor technology. For nuclear power systems with supercritical fluids as working fluids, they are related to the use of supercritical fluids to achieve efficient heat transfer. The strong physical distortion of physical properties makes the prediction of heat transfer deterioration extremely challenging. Based on the development of China's supercritical fluid nuclear power technology, this project takes the boundary layer structure of supercritical fluid as the main research object, and studies the boundary layer characteristics induced by physical distortion in the pseudocritical region. The flow field and temperature field distribution information in the supercritical fluid wall boundary layer are obtained, and the supercritical fluid wall boundary layer flow theory and heat transfer theory framework are constructed. The relationship between the microscopic mechanism in the boundary layer and the heat transfer characteristics of macroscopic supercritical fluids will be established. It provides a theoretical basis for thermal hydraulic research of supercritical fluid nuclear power system.

超临界二氧化碳布雷顿循环系统和超临界水冷堆是以超临界流体为工质的新型核能动力系统，前者被认为是替代目前大规模使用的蒸汽动力装置、实现动力技术变革的革新性方向，后者是被第四代核能系统国际论坛确定的六种极具发展潜力的核能系统中唯一的水冷堆，代表水堆技术的未来发展方向。对于以超临界流体为工质的核能动力系统，都涉及利用超临界流体实现热量高效载出。传热恶化是超临界流体核能系统热工设计的重要参量。超临界流体在拟临界点的物性畸变使其传热恶化预测极具挑战。本项目立足我国超临界流体核能动力技术发展需求，着眼于超临界流体的传热恶化物理现象，以边界层结构为主要切入点，开展拟临界区物性畸变诱导下的边界层特征研究，获得传热恶化条件下壁面边界层内的流场和温场分布信息，建立边界层内微观机理与宏观传热特性联系，提出传热恶化的诱发、发展及演化机制，为超临界流体核能动力系统热工水力研究提供理论基础。

超临界二氧化碳布雷顿循环系统和超临界水冷堆是以超临界流体为工质的新型核能动力系统，前者被认为是替代目前大规模使用的蒸汽动力装置、实现动力技术变革的革新性方向，后者是被第四代核能系统国际论坛确定的六种极具发展潜力的核能系统中唯一的水冷堆，代表水堆技术的未来发展方向。对于以超临界流体为工质的核能动力系统，都涉及利用超临界流体实现热量高效载出。传热恶化是超临界流体核能系统热工设计的重要参量。超临界流体在拟临界点的物性畸变使其传热恶化预测极具挑战。本项目立足我国超临界流体核能动力技术发展需求，着眼于超临界流体的传热恶化物理现象，以边界层结构为主要切入点，开展了拟临界区物性畸变诱导下的边界层特征研究，获得了壁面边界层内的温场分布信息，获得了可反映变物性特征的超临界流体壁面边界层理论模型，完成了基于物性模型构建的超临界流体热质输运直接数值模拟方法，利用直接数值方法完成计算模拟，获得边界层湍流涡结构与湍流热流图像，建立了边界层内微观机理与宏观传热特性联系，提出传热恶化的诱发、发展及演化机制，为超临界流体核能动力系统热工水力研究提供理论基础。