基于ABB Atom 3×3棒束再淹没实验,运用RELAP5建立其实验装置的定流量再淹没计算模型,通过与实验结果做比对验证模拟的有效性,研究在高、低两种注水流量下从底部再淹没高温棒束通道时的不同骤冷现象,分析期间的流动形态、传热特性,液位进程,先驱冷却效果差异等.模拟结果表明:低流量下主液位落后于骤冷前沿,高流量下骤冷前沿明显落后于主液位;通过对比发现在高流量下的高液位为高温壁面带来更强的先驱冷却,使壁面温度更快的降到再湿温度,而低流量下几乎匀速上升的液位变化进程对前沿下游的高温壁面冷却较慢,需要更长的时间才能降到再湿温度.这些分析将为研究此模型下的重力注水打下坚实的基础.%Based on ABB Atom 3×3 bundle reflooding experiment,RELAP5 code is used to build numerical model for reflooding phenomena with constant flow rate. Comparison between the numerical results and experiment results is conducted to verify the numerical model. Afterthat,the cases with high and low mass flow rate are investigated,focusing on the flow condition,heat-transfer characteristic,water level process and precursory cooling effect during the reflooding. The results show that the main liquid level is always behind quench front under low flow rate,while it is completely reversed under high flow rate. Though comparison,it shows that high water level at large flow rate bring more powerful precursory cooling effect for high-temperature cladding than the water level under low flow which nearly rises at a constant speed. This analysis will lay a foundation for gravity reflooding investigation under this numerical model.
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