Abstract: For the ceramsite backfill layer at the bottom of the molten salt tank,a corresponding particle simulation model was established based on the EDEM discrete element software platform to simulate the compaction and backfilling process of the ceramsite layer as well as the full-tank operation condition.The research focused on examining the mechanical effects of three pre-compaction processes (natural stacking,single pre-compaction,and 8-stage segmented pre-compaction) on the compression deformation and stress distribution in the ceramsite layer,while also analyzed the influence of different particle size ranges (5-10,10-15,and 15-20 mm) on the heat transfer behavior.The results show that:(1) under an 8-stage segmented pre-compaction process with a layer height of 1.6 m,particle sizes ranging from 5 to 20 mm,and a heavy-tank load of 50 000 t,the maximum internal stress of the ceramsite ranges from 8.0 to 14.4 MPa,with uniform pressure distribution and an overall settlement of 20.44 mm;(2) as the particle size increases,the heat transfer distance gradually extends while the average heat flux decreases;this indicates that smaller particles provide better thermal insulation,with a heat transfer distance of 185.73 mm and an average heat flux of 0.49 W·m^-2 over 50 h,whereas larger particles exhibit higher thermal conductivity and poorer insulation,allowing heat to dissipate more readily,with a corresponding heat transfer distance of 195.65 mm and an average heat flux of 2.31 W·m^-2.

Key words: discrete element, molten salt tank, ceramsite layer, settlement

摘要： 针对熔盐罐底部的陶粒回填层,基于EDEM离散元软件平台,构建相应的颗粒仿真模型,对陶粒层压实回填工艺及满罐工况模拟,重点考察预压实工艺(自然堆积、一次预压实、8次分段预压实)对陶粒层压缩变形与应力分布的力学影响,并进一步分析了不同粒径分布(5~10、10~15、15~20 mm)对陶粒层传热特性的作用规律。结果表明:1)陶粒层高度1.6 m,陶粒粒径范围5~20 mm,采用8次分段预压实工艺,重罐5万t加载,其陶粒内部最大应力范围为8.0~14.4 MPa,应力分布均匀,总沉降量为20.44 mm。2)随着陶粒粒径的增大,热量传递距离逐渐增加,而平均热通量则下降,表明小粒径颗粒堆具有更优异的隔热性能,其在50 h时的热量传递距离为185.73 mm,平均热通量为0.49 W·m^-2;而大粒径颗粒堆的热传导效率更高,隔热性能最差,热量更容易扩散,其热量传递距离为195.65 mm,平均热通量为2.31 W·m^-2。

关键词: 离散元, 熔盐罐, 陶粒层, 沉降量