PQUENCH-A 3-D quench propagation code using a logical coordinate system

A computer program was developed to model the effects of normal region propagation in the longitudinal direction (along the conductor) and in the two transverse directions in a superconducting coil in a multicoil system. A simulation of 3-D quench propagation in real space was done using a logical coordinate system in which each magnet is transformed into a single long conductor which is divided into finite-length elements. Since an element can be associated with geometry-related information such as the element length, the local magnetic field influence coefficients, and the relationship to adjacent elements in 3-D, the quench propagation in any type of 3-D configuration can be simplified to a 1-D problem. As the growth of the normal region is determined, the transient current decay is calculated based on increases in conductor temperature and resistance. This calculation can be done for multiple, inductively coupled systems through the use of a circuit analysis subroutine. The code logic is described, and results are given for calculated versus measured quench times in a single-coil system