数値シミュレーションによるNb_3Sn素線の波状曲げ変形時の超電導特性の評価 [in Japanese] Numerical Simulation of Critical Current Performance in Nb_3Sn Strand Subjected to Periodic Bending Deformation [in Japanese]
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In the ITER Engineering Design Activity (EDA), four Nb<sub>3</sub>Sn model coils were developed and successfully tested. However, it was revealed that the critical current of the conductor degraded with the increase of electromagnetic force. One of the explanations of this phenomenon is a strand bending caused by enormous electromagnetic force. The authors therefore developed a simulation code using the distributed circuit model to investigate dependency of the critical current performance on the periodic bending deformation. The simulation results were in good agreement with the experiments. The dependence of the critical current on the periodic transverse load, temperature, periodic load pitch, thickness of Ta barrier which prevents Cu stabilizer to be contaminated by Sn, twist pitch of the strand and RRR of the bronze matrix was investigated using the developed code. The results showed that the critical current degraded less with decreasing the pitch of the transverse load and increasing the Ta barrier thickness. It suggests that the shorter cabling pitch and the larger bending stiffness prevent the critical current degradation.
- IEEJ Transactions on Power and Energy
IEEJ Transactions on Power and Energy 128(6), 853-859, 2008-06-01
The Institute of Electrical Engineers of Japan