基于OpenFOAM的熔融池自然对流传热与凝固数值研究

熔融物堆内滞留是第3代核电技术重要的严重事故缓解措施之一,堆芯熔融池在压力容器下封头壁面的热流密度分布直接影响该策略的有效性。本文基于开源的数值计算流体力学软件平台OpenFOAM,应用相变模型和浮升力模型二次开发了用于模拟堆芯熔融物由内热源或温差驱动的自然对流传热与相变求解器。应用该求解器模拟了瑞典皇家理工学院开展的二维氧化池与金属层耦合传热试验,获得了氧化池和金属层硬壳的相场,以及熔融池内的温度分布及沿容器壁面的热流密度分布。计算结果表明,该模型可用于熔融物凝固与自然对流的模拟,为深入分析核电厂采用熔融物堆内滞留措施后熔融池的行为奠定了基础。

Numerical Investigation on Natural Convection and Solidification of Molten Pool with OpenFOAM

The in-vessel retention is adopted by the third generation nuclear power technology as an important severe accident mitigation strategy. The integrity of reactor pressure vessel depends on the heat flux distribution of molten pool. In present study, the solidification model in open source CFD software OpenFOAM was applied to simulate solidification and natural convection which was driven by internal heat source or temperature difference. The stratified molten pool heat transfer experiment carried out by Royal Institute of Technology was analyzed in the paper, and the solidified crust, temperature and heat flux distributions were obtained. The simulation results were compared with experimental data. It is shown that this numerical method can be used in the simulation of natural convection and solidification of molten pool, and it will probably be used in the analysis of molten corium behavior in reactor lower head.