Abstract—

Methodical approaches to verification of a CFD-class code for modeling fluid dynamics and heat transfer processes within the boundaries of a fuel assembly (FA) used in liquid metal cooled reactors are proposed. For verifying the code, experiments that take into account the specific features pertinent to the flow of and heat transfer in liquid metal coolants in the fast reactor FAs with spacer grids were selected. The experiments cover the following regimes: turbulent flow of and heat transfer in liquid metals in the stabilized and nonstabilized sections in simple and complex shaped channels for which the flow structure in the near-wall region is the determining one; turbulent flow in channels containing elements that cause flow separation and redistribution of the flow rate over the cross section, and flow in channels containing abrupt flow constriction/expansion. Proceeding from the need to save computation resources in solving practical problems, the high Reynolds number turbulence model was used, which does not pose the requirement of fulfilling the y⁺ ≈ 1 criterion for the dimensionless distance from the first computational node to the wall. The computations were carried out with the use of the high Reynolds number Realizable k–ε turbulence model with the standard near-wall function. The local Weigand model for the turbulent Prandtl number Pr_t, applied in a wide range of Pr number values, including those for liquid metals, was used. The maximum deviations of the calculated values from the experimental data for the practically important parameters are estimated.

中文翻译：

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验证用于液体金属冷却反应堆燃料组件建模的CFD级软件工具

摘要—

提出了一种用于验证CFD类代码的方法，该代码用于对在液态金属冷却反应堆中使用的燃料组件（FA）边界内的流体动力学和传热过程进行建模。为了验证代码，选择了考虑到与带有间隔栅的快速反应堆FA中液态金属冷却剂的流动和传热有关的特定特征的实验。实验涵盖以下方案：在简单和复杂形状的通道中，稳定壁和不稳定壁中液态金属的湍流和传热，其中近壁区域的流动结构是决定性因素。通道中的湍流，其中包含导致截面分离和流速重新分配的元素，并在包含突然流量限制/膨胀的通道中流动。从解决实际问题中节省计算资源的需求出发，使用了高雷诺数湍流模型，这并没有提出满足条件的要求。 从第一个计算节点到墙的无量纲距离的y ⁺ ≈1标准。使用具有标准近壁函数的高雷诺数可实现k –ε湍流模型进行计算。使用了湍流普朗特数Pr _t的局部Weigand模型，该模型在广泛的Pr值值（包括液态金属的Pr值）中应用。对于实际重要的参数，估算值与实验数据的最大偏差是估算值。