氦氙工质在绕丝环形通道内热工水力特性数值研究

Numerical Study on Thermal-Hydraulic Characteristics of He-Xe Mixture in a Wire-Wrapped Annular Channel

摘要: 以氦氙(He-Xe)混合气体为冷却剂的布雷顿循环气冷堆被视为兆瓦级空间能源系统中最合理的技术之一，当前绕丝对He-Xe混合气体流动传热特性的影响研究较少，影响机理尚未可知。本研究对He-Xe混合气体在绕丝环形通道中的流动传热进行了数值模拟，分析了四种不同形状绕丝通道中，氦氙混合气体不同雷诺数下的流动换热特性，得到温度场分布，努塞尔数，以及摩擦阻力系数，以及综合换热性能评价指标(PEC)，比较了四种不同绕丝结构与无绕丝结构的流动传热差异，分析了绕丝带来的综合换热性能差异。研究结果表明，在高雷诺数工况下(Re > 5675)，梯形绕丝能提升环形通道内的传热，而圆形、方形、倒梯形绕丝使得传热变差；在热工水力性能评价指标下，梯形绕丝在高雷诺数工况下有较好的强化传热效果。研究结果可为He-Xe空间堆堆芯设计和优化提供参考。

Abstract: The Brayton-cycle gas-cooled reactor using helium-xenon (He-Xe) mixture as coolant is considered one of the most promising technologies for megawatt-class space power systems. However, few studies have investigated the influence of wire wraps on the flow and heat transfer characteristics of He-Xe mixtures, and the underlying mechanisms remain unclear. In this work, numerical simulations are performed to study the flow and heat transfer behavior of He-Xe mixture in an annular channel with wire wraps. Four different wrap cross-sectional shapes are examined over a range of Reynolds numbers. Key parameters including temperature distribution, Nusselt number, friction factor, and thermal-hydraulic performance ratio (PEC) are analyzed to evaluate the overall heat transfer enhancement. A comparative analysis between wrapped and bare channels is conducted to assess the comprehensive thermal performance difference introduced by the wire wraps. Results indicate that the trapezoidal wrap enhances heat transfer in the annular channel, whereas the circular, square, and inverted-trapezoidal wraps worsen heat transfer. Under the PEC criterion, the trapezoidal wrap exhibits superior performance at high Reynolds numbers. The findings provide valuable references for the core design and optimization of He-Xe cooled space reactors.