Two-Dimensional Anisotropic Model of YBCO Coated Conductors

The ability of second-generation YBCO coated conductor (CC) tapes to transport high current densities at high temperature, i.e., up to 77 K, and at very high magnetic fields, i.e., above 20 T, are pushing the use of these tapes in various applications, from magnet to power system technologies. An accurate study of their quench behavior is mandatory for the design and safe use of cables and magnets manufactured with this ceramic superconducting material. A new 2-D finite-element method (FEM) numerical quench model, which is called anisotropic model of YBCO CCs, was built for this purpose in the COMSOL Multiphysics environment. One of the most difficult issues in the modeling of the YBCO tapes with the FEM is their high aspect ratio due to the very small thickness of the YBCO layer, about 1 mu m. In the model developed, the problem of the high aspect ratio of the tape is tackled by multiplying the tape thickness by a constant factor and then compensating the heat and electrical balance equations through the introduction of material anisotropic properties. The FEM model is validated by comparison with literature experimental data on minimum quench energy and normal zone propagation velocity.