ABSTRACT For the structural integrity evaluation of pressurized water reactor (PWR) steam generator (SG) tubes subjected to transient hydraulic loading, determination of the tube-to-tube gap velocity and static pressure distributions along the tubes is prerequisite. This paper addresses both computational fluid dynamics (CFD) and analytical approaches for predicting the tube-to-tube gap velocity and static pressure distributions during blowdown following a feedwater line break (FWLB) accident at a PWR SG. First of all, a comparative study on CFD calculations of the transient velocity and pressure distributions in the SG secondary sides for two different models having 30 or no tubes is performed. The result shows that the velocities of sub-cooled water flowing between any adjacent two tubes of a tubed SG model during blowdown can be roughly estimated by applying the specified SG secondary side porosity to those of the no-tubed SG model. Secondly, simplified analytical approximate solutions for the steady two-dimensional SG secondary flow velocity and pressure distributions under a given discharge flowrate are derived using a line sink model. The simplified analytical solutions are validated by comparing them to the CFD calculations.

中文翻译：

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给水管线破裂排污过程中核蒸汽发生器二次侧流场的数值分析预测

摘要 对于承受瞬态液压载荷的压水反应堆 (PWR) 蒸汽发生器 (SG) 管的结构完整性评估，确定管间间隙速度和沿管的静压分布是先决条件。本文讨论了计算流体动力学 (CFD) 和分析方法，用于预测 PWR SG 给水管线破裂 (FWLB) 事故后排污期间的管间间隙速度和静压分布。首先，对具有 30 个管子或没有管子的两种不同模型的 SG 二次侧瞬态速度和压力分布的 CFD 计算进行了比较研究。结果表明，通过将指定的 SG 二次侧孔隙率应用于无管 SG 模型的孔隙率，可以粗略估计排污期间在有管 SG 模型的任何相邻两管之间流动的过冷水的速度。其次，使用线汇模型推导出给定排放流量下稳态二维 SG 二次流速和压力分布的简化解析近似解。通过将简化的解析解与 CFD 计算进行比较来验证它们。