Research Quenches Need for Mixed-Dimensional Coil Modeling

  • Published
  • By Joseph Gordon, Femando Rodriguez
  • Propulsion
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  Motivated by the need for more in-depth study of yttrium barium copper oxide-coated superconducting coil--a technology of substantial value to compact, lightweight power applications of great interest to the Air Force--Florida A&M University researchers created a hybrid, finite element model of conducting coil (i.e., conductor) quench dynamics. Based on a mixed-dimensional tape model, the new technique enables a given conductor's full, three-dimensional representation to be replaced with an abridged, two-dimensional version, providing high-fidelity results and reduced computational requirements compared to commercial software approaches for modeling 3-D quench propagation in superconducting coils.

Maintaining functionality at temperatures approaching 77 K, YBCO-coated tapes are among the most promising high-temperature superconducting wraps, enabling development of advanced conductors, coils, and motors/generators. However, one factor limiting the widespread application of this technology is the poorly understood behavior of the YBCO-coated conductor under a quench event, when it loses its HTS capability. While YBCO's inherently low thermal diffusivity inhibits a quench from spreading quickly enough throughout the conductor to prevent a failure, a detailed finite element analysis of configurations that could aid propagation velocity would preempt this scenario. Unfortunately, such analysis has heretofore proven difficult because of the coated conductor's large aspect ratios (micron's thickness to millimeter's width).

The FAMU research exploits the fact that a 2-D representation of the conductor--one incorporating its detailed physical interfaces and behavior--is easily derived from 3-D modeling processes and, further, enables associated analysis that is not only faster (about 8 times) but less resource intensive (about 1/3 the finite elements used). Using this technique, the FAMU researchers have been able to predict the quench behavior observable in existing (in-development) coils. Already reported in the Institute of Electrical and Electronics Engineers' IEEE Transactions on Applied Superconductivity publication (Volume 19, Issue 3, Part 2), these work results were also part of proceedings at the 2010 Applied Superconductivity Conference.