COPRA双层熔池湍流模型优选

Optimization of turbulent models for a corium pool research apparatus(COPRA)double⁃layer melt pool

为了预测下封头内双层熔池的流动和传热过程,基于不同湍流模型,同时采用凝固熔化模型对堆芯熔池研究装置(corium pool research apparatus,COPRA)双层熔池实验进行计算流体力学(CFD)数值模拟,通过数值计算获得准稳态下熔池的温度、沿壁面的热流密度与内壁面壳层的分布,将模拟结果与实验值进行比较,评价不同湍流模型的适用性和准确性,并进行湍流模型优选。结果表明,壁面模化大涡模拟(WMLES)湍流模型对下封头内双层熔融池流动与传热模拟的准确性和适用性最好;基于WMLES湍流模型,氧化层温度随着熔池高度增大而增大,氧化层上部存在强烈的湍流,在熔池底部的壳层最厚。

In order to predict the flow and heat transfer process of a double-layer molten pool at the lower head,computational fluid dynamics(CFD)numerical simulation of a corium pool research apparatus(COPRA)double-layer molten pool experiment has been carried out for different turbulence models by adopting the solidification melting model.Through numerical calculation,the quasi-steady state temperature of the molten pool,the heat flux along the wall and the distribution of the crust were obtained.The simulation results were compared with the experi-mental values to evaluate the applicability and accuracy of different turbulence models,and the turbulence model was optimized.The results show that the wall-modelled large-eddy simulations(WMLES)turbulence model has the best accuracy and applicability for the simulation of the flow and heat transfer in the double-layer molten pool at the lower head.The WMLES turbulence model shows that the temperature of the oxide layer increases with the increase of the height of the molten pool.Intense turbulence is observed in the upper region of the oxide layer,and the thickest shell forms at the bottom of the molten pool.