CFETR CSMC装配误差下的电磁状态研究

中心螺旋管模型线圈是为了积累中心螺线管线圈设计和制造经验而预研的一套混合超导磁体线圈,该线圈由五大模块组成,高场区采用Nb_3Sn线圈,低场区采用NbTi线圈,可以满足紧凑型聚变装置对低纵横比的要求.然而模型线圈各模块结构复杂、尺寸庞大在装配过程中不可避免的存在装配误差,线圈励磁以后产生的非对称磁场和电磁力将分别影响等离子体的旋转和线圈整体的稳定性.为了详细分析装配误差对线圈磁场和电磁力的影响,选取模型线圈在装配过程中可能出现的典型的装配误差,基于电流丝等效模型计算了NbTi线圈偏置以后Nb_3Sn内外线圈上的磁场和电磁力.计算结果表明,由于装配误差,线圈磁场沿环向呈不均匀分布,轴向电磁力合力不为零;轴向和径向装配误差对线圈磁场和电磁力的影响存在明显的差异;电磁力随着装配误差呈线性增长,当线圈装配误差较大时将引发数倍于线圈自重的电磁力;该研究结果可为偏置状态下模型线圈的耦合场分析和线圈模块的装配方案设计优化提供参考.

The Electromagnetic State Analyses of CFETRC SMC under Assembly Error

The Central Solenoidal Model Coilis a set of hybrid superconducting coil, the R&D of which is aiming at accumulating design and fabrication experience for Central Solenoid. The coil is composed of five modules. And the Nb3Sn coil is used in the high field region, the NbTi coil is used in the low field region.The design could satisfy the low aspectratio requirement of compacted fusion device.However, due to the complicated structure and huge geometric size, the assembly error is inevitable during the assembling process. Once the coil is energized,the induced non-symmetric magnetic density and electromagnetic force will impact the plasma rotation and the stability of CSMC respectively. In order to study the magnetic field and electromagnetic force under assembly error, the typical assembly errors mighty occur during the assembling process are chosen. And the magnetic density and electromagnetic force of inner Nb3Sn coil under the misalign state of NbTi coil are calculated based on elliptical integral. The calculation results indicate the magnetic densityis non-uniform along the toroidal direction and the resultant electromagnetic force in the axial direction is not zero anymore. The axial and radial assembly errors have different impact on the magnetic density and electromagnetic force.The electromagnetic force increases linearly with assembly error. And the electromagnetic force will be several times of the coil dead weight under the relatively larger assembly error. The analysis results provide the reference for the coupling analysis of CSMC in the misalign state and also for the design optimization of CSMC assembly scheme.