Ring-Type Support Concept for Twisted Coils (Finite Element Simulation)

摘要

A Ring-type support concept is introduced in this report. This is an alternative to the Front support system where a stellarator reactor coil (Wendelstein VII-AS type) is supported at the front region (near to the torus axis) to take up the resultant centering force. A coil is also supported sidewise to stop tilting moments. With the Ring-type support system, a coil is supported all along its circumference and sidewise as well. The twisted coils within the magnetic field are subjected to forces and moments which are complex in nature. The coils are usually sensitive to support conditions and the stresses response accordingly on how they are being supported. Applying the usual Front support concept the stresses in a coil with superimposed bending stresses may be rather high and critical with the increased magnetic forces. They may even exceed the limit of present technical feasibility. Whereas a Ring-type support system actually tends to reduce the bending moments and thus causes a considerable drop in mechanical stresses within a coil. The finite element computations have been carried out assuming a coil being a superconducting one and therefore no temperature rise within a coil may be considered. Also the forces and stresses resulting from cooling down and different thermal expansion coefficients are not treated in this report. A Ring support can either be an inward or an outward type and it is applicable also for planar coils. (ERA citation 10:008009)