Study on the Flow Field Characteristics of the Mixing Wing in the Fuel Rod Bundle Region of a Pressurized Water Reactor

Abstract: The mixing wing plays an important role in reducing the hot spot factor of the reactor core, but there is currently limited research on the influence of the fine structure of the mixing wing on the flow field. In order to gain a deeper understanding of the influence of the characteristics of the mixing wing structure on the thermal and hydraulic performance of the reactor core, a study was conducted on the correlation between the mixing wing structure and the flow field. Firstly, through geometric automation configuration and calculation technology, parameterized and automated construction of a tearing type mixing wing structure and CFD calculation are achieved. Secondly, through orthogonal design and simulation analysis of the parameters of the mixing wing structure, the influence of the mixing wing structure on thermal parameters such as flow field pressure drop and cross flow velocity was clarified. Under the geometric structure of the article, the maximum difference in outlet pressure between different mixing wings is 1.1 kPa, which is 41% of the average pressure drop in the entire computational fluid domain. The maximum difference in cross flow velocity under different mixing wings is 1.1 m/s, which is 173% of the average cross flow velocity. The angle of the mixing wing is strongly correlated with the flow field, followed by the shape and length of the mixing wing, and a better mixing wing has been designed. Provide design basis for subsequent research and engineering application of mixing wing structures.