CFETR 胀板式杜瓦冷屏的初步设计与热分析

Preliminary design and thermal analysis of CFETR expansion platecryostat thermal shield

为进一步减少托卡马克装置中超导磁体的热负荷,将胀板结构应用于杜瓦冷屏(CTS)中,代替传统管板式冷屏结构。胀板结构是一种在屏蔽板间形成冷却介质流动的夹层空间结构。选择304LN不锈钢作为CTS材料,选择模压-焊接作为CTS成型方式,选择氦气作为冷却剂。确定了最佳焊点参数及屏蔽板参数。首先根据辐射热原理计算杜瓦冷屏表面热流密度,然后应用流体仿真软件CFX对杜瓦冷屏进行热分析,得到了杜瓦冷屏面板温度及进出口压差。分析表明,胀板式杜瓦冷屏面板的温度分布均匀,相比管板式杜瓦冷屏有显著降低,理论上证明了胀板式杜瓦冷屏结构的优越性。

In order to further reduce the thermal load of the superconducting magnets in the tokamak,the expansion plate structure is applied to the Cryostat Thermal Shield(CTS),which replaces the traditional tube-sheet CTS structure.The expansion plate structure is a sandwich space structure that allows coolant to flow between the shielding plates.304LN stainless steel is selected as the CTS material,molding-welding is selected as the CTS forming method,and helium gas is selected as the coolant.The optimal solder joint parameters and shielding board parameters are determined.Firstly,the heat flux density on the surface of the CTS is calculated according to the principle of radiant heat,and then the thermal analysis of the CTS is carried out by using the fluid simulation software CFX to obtain the temperature of the CTS plates and the pressure drop between the inlet and outlet.The analysis shows that the temperature distribution of the expansion plate CTS is uniform,the temperature is significantly lower than that of the tube-sheet CTS,and then the superiority of the expansion plate CTS structure is proved theoretically.