Two-dimensional quench propagation model for a three-dimensional high-temperature superconducting coil

The results of an experimental and analytical study of quench propagation in a three-dimensional, layer-wound, high-temperature superconducting magnet are presented. The test magnet is wound "dry" with silver-sheathed Bi-2223/Ag tape. It operates in zero background field under quasi-adiabatic conditions at 20 K and above, with a transport current of 50-100 A. Quenching is initiated by a stainless steel heater attached to one turn of the outermost layer. The resulting thermal response was recorded through voltage measurements across regions of the conductor near the heater. Quench events are simulated by a numerical code using the finite-difference method to solve the two-dimensional transient heat conduction equation. The model indicates that thermal contact resistance has a dominant effect on propagation in the transverse direction (across layers).