Numerical investigation of pressure drop and flow behavior in a 9 × 9 helical-cruciform fuel assembly

IF 2.1 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Nuclear Engineering and Design Pub Date : 2025-09-24 DOI:10.1016/j.nucengdes.2025.114448

Ugur Karakurt , Hansol Kim , Joseph Seo , Yassin A. Hassan

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引用次数: 0

Abstract

The helical-cruciform fuel (HCF) design features helically twisted rods with a four-lobed cross-section, increasing the surface-to-volume ratio compared to conventional cylindrical rods. This geometry enhances heat transfer and coolant mixing while reducing peak fuel temperatures. The self-supporting rod arrangement eliminates spacer grids, reducing flow obstruction and pressure losses. These characteristics enable higher reactor power density and lower operating temperatures in current and next-generation reactors. This study numerically investigates pressure drop and flow characteristics in a 9 × 9 HCF assembly using Reynolds-Averaged Navier-Stokes (RANS) simulations with the

k

ω

Shear Stress Transport (SST) turbulence model. Preliminary analyses of 3 × 3 to 11 × 11 assemblies demonstrated that the 9 × 9 configuration is the minimum bundle size required to accurately represent essential flow behavior in larger assemblies. Entrance length analysis at Re = 21,121 shows fully developed flow after one helical pitch. The CFD model is validated against experimental pressure drop data. Flow regime boundaries are estimated at Reynolds numbers of approximately 861 (laminar-to-transitional) and 9,755 (transitional-to-turbulent). A friction factor correlation covering Re = 119 to 21,958 is developed and compared with existing correlations. The flow characteristics at Re = 21,121 were analyzed within subchannels and inter-subchannel gaps.

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9 × 9螺旋-十字形燃料组件压降与流动特性数值研究

螺旋-十字形燃料（HCF）的设计特点是螺旋扭曲的燃料棒具有四个叶状截面，与传统的圆柱形燃料棒相比，增加了表面体积比。这种几何形状增强了传热和冷却剂混合，同时降低了峰值燃料温度。自支撑杆的布置消除了间隔栅，减少了流体阻塞和压力损失。这些特性使当前和下一代反应堆的功率密度更高，工作温度更低。本研究采用k-ω剪切应力输运（SST）湍流模型，采用reynolds - average Navier-Stokes （RANS）模拟，对9 × 9 HCF组件的压降和流动特性进行了数值研究。对3 × 3至11 × 11组件的初步分析表明，9 × 9配置是准确表示大型组件基本流动行为所需的最小束尺寸。在Re = 21,121处的入口长度分析表明，一个螺旋螺距后流动完全发育。利用实验压降数据对CFD模型进行了验证。流型边界的雷诺数估计约为861（层流到过渡）和9755（过渡到湍流）。建立了覆盖Re = 119至21,958的摩擦系数相关性，并对现有相关性进行了比较。分析了Re = 21,121时子通道内和子通道间的流动特性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nuclear Engineering and Design 工程技术-核科学技术

CiteScore

3.40

自引率

11.80%

发文量

377

审稿时长

5 months

期刊介绍： Nuclear Engineering and Design covers the wide range of disciplines involved in the engineering, design, safety and construction of nuclear fission reactors. The Editors welcome papers both on applied and innovative aspects and developments in nuclear science and technology. Fundamentals of Reactor Design include: • Thermal-Hydraulics and Core Physics • Safety Analysis, Risk Assessment (PSA) • Structural and Mechanical Engineering • Materials Science • Fuel Behavior and Design • Structural Plant Design • Engineering of Reactor Components • Experiments Aspects beyond fundamentals of Reactor Design covered: • Accident Mitigation Measures • Reactor Control Systems • Licensing Issues • Safeguard Engineering • Economy of Plants • Reprocessing / Waste Disposal • Applications of Nuclear Energy • Maintenance • Decommissioning Papers on new reactor ideas and developments (Generation IV reactors) such as inherently safe modular HTRs, High Performance LWRs/HWRs and LMFBs/GFR will be considered; Actinide Burners, Accelerator Driven Systems, Energy Amplifiers and other special designs of power and research reactors and their applications are also encouraged.