中文摘要：

基于大型熔融池换热特性试验台架COPRA,分别采用水和非共晶摩尔比例20%NaNO_3-80%KNO_3混合物作为熔融物模拟物,进行熔融池换热特性试验研究。熔融池瑞利数Ra′可达到1016量级,与反应堆真实情况下的量级一致。试验对比了水试验和熔盐试验得到的熔融池温度场分布和壁面热流密度分布。结果表明,熔融物硬壳的形成对熔融池换热特性产生了明显影响。试验拟合得到了熔融池换热特性关系式,其中热流密度关系式与国际上其他试验得到的结果符合得较好。在同等Ra′量级下,COPRA试验得到的熔融池向下封头壁面的传热量较国际上其他试验的结果低。

英文摘要：

Large scale COPRA experiments were performed to study the natural convection heat transfer in corium pools.Both water and a non-eutectic binary mixture of20%NaNO_3-80%KNO_3（in mole fraction）compositions were employed as the simulant material.The Rayleigh number within the pool could reach up to 1016,matching those in the prototypical situation for PWR.The comparisons of the pool temperature and heat flux distributions from water and molten salt experiments show that the crust formation along the inside curved wall is of significant impact to the heat transfer phenomenon in the melt pool.Heat transfer correlations were obtained from COPRA experiment and the heat flux distribution compared well with other experiments.The downward heat transfer towards the curved wall is lower than those from other experiments within the same range of Rayleigh number.