兆瓦级强流离子源地电极的热应力计算与分析

Analysis of thermal stress for exit grid of megawatt level high current ion source

在设计用于高能中性束注入装置的强流离子源时,最关键的环节是对用于产生兆瓦级离子束的引出电极进行热-应力分析。以EAST-NBI强流离子源地电极为模型,考虑受均匀热流载荷作用下电极在主动冷却过程中的耦合传热问题,利用CFD和有限元联合求解的方法进行了热应力分析,得到了固体结构和流场的瞬态温度场、结构应力分布及变形情况。结果表明在热流载荷密度不超过2MW.m-2、冷却水质流速率为(0.125～0.25)kg.s-1时,电极温度场在4s内达到稳态,而且最大Von-Mises等效应力值小于材料屈服强度,不会发生塑性变形。

To design the high-power neutral beam injection system,it is essential to make a thermo-mechanical design of acceleration grids for producing several tens of MW ion beams.Taking the conjugate heat transfer in smooth cooling tubes into account,analysis of thermal stress for the exit grid of EAST-NBI high current ion source is carried out by using the CFD and FEM software.The distribution and evolution of temperature in the solid and coolant,the distribution of stress and deformation of the structure are obtained,the result indicates that the temperature in the exit grid reach stable value within 4s and no plastic deformation occurs with max.Von-Mises equivalent stress less than yield strength as the heat loading less than 2MW·m-2 with cooling water mass flow rate ranged from（0.125～0.25）kg·s-2.