HT-7U超导托克马克纵场线圈等效模量的数值分析

Effective modulus of cables for super-conducting toroidal field (TF) coils of HT-7U tokamak device

HT-7U托克马克装置的纵场线圈是由多种材料组成的具有周期性分布的大型复杂结构,线圈可视为由超导线、支撑结构和绝缘材料组成的复合材料,结构极其复杂。整个线圈工作在液氦温区。在设计阶段对其宏观等效力学性能进行数值分析计算是十分必要的,但要对整个线圈直接进行有限元分析或实验是极其困难的,主要利用均匀化方法对其进行等效处理,从而分析计算其宏观等效模量,为线圈的设计和评估提供参考依据。另外本文对均匀化方法的边界条件进行了一些改进,提出了更加合理的三维边界条件。

The super-conducting toroidal field (TF) coil system of HT-7U is a very important part of the HT-7U superconducting tokamak device, and it is made of sixteen D-shaped coils. The superconducting coils may be regarded from the structural point of view as unidirectional composites. They are made up of a large number of superconductors in the axial direction, bound together by insulating material. These superconductors are cable-in-conduit conductors (CICC) which have rather complex structures. In order to design the mechanical structure of the TF system, it is very necessary to analyse the mechanics characteristics at the working temperature (liquid helium temperature). But the internal structure of this device is very difficult to calculate directly by the finite element method because of its complex structures. Considering all these facts, the model for simulating the effective elasticity modulus of the periodic superconducting coil cable is based on the Homogenization method. All the numerical experiments have been carried out by using the program HOMOG for the Representative Volume Element (RVE) of the composite. By using the program HOMOG the effective elasticity modulus of TF coil with 100%, 62.2% superconducting cables as well as without superconducting cables are calculated. The results will be helpful to analyses of the mechanics behavior of HT-7U tokamak device. A new three-dimension boundary condition of homogenization method is also given.