基于DEM的重金属颗粒流靶区输运过程研究

摘要

基于固体和液体散裂靶,近期国内外研究学者提出了一种新概念重金属颗粒流散裂靶.加速器驱动次临界系统(ADS)中重金属散裂靶在高能质子轰击作用下,出现能量沉积现象,而这些热量必须进行有效冷却以保证ADS的安全性.本文针对这种新概念颗粒流靶对靶区产生的高额热量的导出效果进行了模拟分析.首先采用蒙特卡罗程序计算450 MeV质子束轰击钨靶后能量沉积的空间分布,并将此作为颗粒流的体热源输入,基于计算流体力学-离散单元法(CFD-DEM)耦合方法对ADS靶区两种不同直径颗粒流的输运过程进行了模拟研究.结果表明,随颗粒直径的减小,靶区内温度分布更为均匀,颗粒流的流动特性更接近流体,颗粒导热性能增强;颗粒流靶中热应力可局限在单个颗粒内部而承受更高的能量沉积,具有更高的安全限值以及更广阔的应用前景.%Based on the solid and liquid targets,many researchers have been devoted to a new conceptual granular target recently.With the impact of high-energy protons on the heavy targets in Accelerator Driven Sub-critical System (ADS),much energy will deposit in the targets,which needs to be removed efficiently.The intent of this paper was to simulate and analyze the thermal-hydraulic characteristics with much deposited energy.The spatial distribution of energy deposition was obtained through bombarding the tungsten target by proton beam with 450 MeV.Based on the coupled CFD-DEM method,the investigation into transport characteristics of granular targets with two different diameters was conducted under the calculated power density.The results indicate that the temperature in target distributes more uniformly with smaller diameter and the cooling performance of particles is enhanced as close to liquid target.In addition,the granular target can undertake higher power density and possess higher safety margin resulting from thermal stress confined within one tungsten sphere,which seems to have a good prospect for developments.