基于一维和三维耦合模型的ITER偏滤器烘烤过程热应力分析

Thermal Stress Analysis during ITER Divertor Baking Process Based on 1D and 3D Coupled Model

中文关键词: 托卡马克  偏滤器  烘烤过程  热应力  一维流动分析

英文关键词: Tokamak  Divertor  Baking Process  Thermal Stress  One Dimensional Flow Analysis

中文摘要:

      偏滤器是托卡马克装置堆内的重要部件，有去除杂质、避免第一壁烧蚀的作用。在装置运行前，要对偏滤器进行烘烤以去除水分及杂质，但在烘烤过程中偏滤器靶板会产生较大的热应力。为了探究偏滤器在不同烘烤速率下的热应力变化，找到能够改善热应力的最大烘烤速率，本文发展了一维流动换热和三维导热耦合计算的模拟方法，对ITER偏滤器换热模块内的流动和温度分布进行分析，并进一步考察了不同烘烤速率下的热应力分布。计算结果显示，烘烤速率对ITER偏滤器的热应力有较大影响，减慢烘烤速率可以明显降低热应力，当烘烤速率小于0.1K/s时烘烤速率对热应力的影响很小。另外，纯铜中间层在烘烤过程中会发生塑性屈服现象，这会减小结构的热应力。

英文摘要:

      Divertor is an important component within vacuum chamber of Tokamak reactor, which is used to absorb the plasma outside the magnetic flow interface to avoid the ablation of first wall. It can remove the helium ash from vacuum chamber as well. Before the running of Tokamak, The divertor needs to be baked to remove moisture and impurities attached to the surface. However, there will be a great thermal stress in the fixed structure of divertor targets during the baking process due to the temperature gradient. The purpose of this study is to study to analyze the thermal stress of ITER divertor under different baking rates and find the best baking rate of ITER divertor that can significantly decrease the thermal stress. A one-dimensional flow and heat transfer model was developed and was further coupled with the three-dimensional heat transfer simulation by FLUENT. The coupling model was applied in the thermal stress analysis of ITER divertor. The results show that the faster the baking rate is, the bigger the maximum thermal stress occurs. When the baking rate is reduced to be 0.1 K/s, the influence of temperature gradient on the thermal stress is extremely small. In addition, it is found that a large shaping yield phenomenon of pure copper interlayer is occurred in the baking process which may lead to the decrease of the thermal stress of support structures.