Electromagnetic force behavior of high temperature superconducting coils coupled with multi-physics fields under different models

Abstract

Rare earth barium copper oxide (REBCO) superconducting tape is the second generation of high temperature superconducting material with strong current carrying capacity and high mechanical strength, which has been studied most recently. In order to better investigate the electromagnetic force distribution characteristics of REBCO superconducting materials after electromagnetic excitation, firstly, the electromagnetic characteristics of superconducting tapes are numerically calculated by H method and T-A method on the basis of finite elements (FE) in this paper, and the effectiveness of T-A method is obtained. Based on this method, the influence of real size model (RS model) and homogenization equivalent model (HE model) on superconducting tape is further studied. The results show that the radial magnetic field reaches a peak of 1.01 T at the middle position of the upper surface of the pancake, while the axial magnetic field reaches a peak of 16.4 T at the inner side of the pancake, which indicates that the axial magnetic field contributes more to the total magnetic field. At the same time, the rationality of the equivalent method is obtained by comparing the calculation results of the RS and HE models. In addition, the mechanical changes of superconducting tapes are studied by T-A method under the HE model. It is found that the hoop stress and radial stress reach the peak values of 64.7 MPa and 6.84 MPa, respectively, and both are tensile stress, indicating that the hoop stress is more likely to cause damage to the superconducting tapes. Finally, the effect of different external tensile strains on the superconducting tape is discussed.