【摘要】 在小堆紧凑性的要求下，环形燃料组件在小堆堆芯方案中具有显著的竞争力。由于环形燃料组件的几何特性和传统棒状燃料组件不同，流动实验是研究其通道热工水力特性、指导燃料组件几何设计的重要手段。本文利用核磁共振成像测速（MRV）技术对3×3环形燃料组件冷却剂通道的全空间三维流场进行测量，分析环形燃料组件冷却剂通道全空间流场分布特性，以及冷却剂在内外通道流量分配特性。结果表明：MRV可以精确解析环形燃料组件通道内外，特别是格架周围的细节流场分布；不同区域内外通道速度分布的差异可能造成传热特性差异；内外通道的横截面积之比基本决定了其质量流量之比。本文的研究证明了MRV技术精确解析三维流场细节的能力，同时为环形燃料组件冷却剂通道的流场研究提供了实验数据支撑。更多还原

【Abstract】 Under the compactness constraints of small modular reactors, annular fuel assemblies demonstrate significant competitiveness in core design schemes. Due to the distinct geometric characteristics of annular fuel assemblies compared to conventional rod-type assemblies,flow experiments are essential for investigating their channel thermal-hydraulic properties and guiding the geometric design of fuel assemblies. In this study, magnetic resonance velocimetry(MRV) is employed to measure the full three-dimensional flow field of coolant channels in a 3×3 annular fuel assembly, with the spatial distribution characteristics of the flow field and the coolant flow rate allocation between inner and outer channels analyzed. The results indicate that MRV can accurately resolve the detailed flow field distribution within both the inner and outer channels of the annular fuel assembly, especially around the spacer grids; differences in velocity distribution between regions may lead to variations in heat transfer characteristics; and the ratio of crosssectional areas between inner and outer channels essentially determines their mass flow rate ratio.This study demonstrates the MRV technology’s ability to precisely analyze the details of threedimensional flow fields, and at the same time provides experimental data support for the flow field research of coolant channels in annular fuel assemblies.更多还原