Numerical Analysis on the Quench Process and Protection of Conduction Cooled ${\rm MgB}_{2}$ Magnet

Abstract

The thermal stability of the superconducting magnet is one of the important issues for MRI system. In this work, the quench behavior of superconducting MgB 2 magnet for MRI is studied by use of the finite element method (FEM) and finite difference method (FDM). This work considers a close winding coil subjected to a thermal disturbance that is a three-dimensional problem. The effective value is adopted in the physical properties of the magnet. The quench propagation velocity (QPV) in various conditions is computed by the parallel-tapes model beforehand.The quench characteristics of the MgB 2 magnet with different parameters of superconducting wires are investigated. The effect of the initial quench location on the quench characteristics and the feasibility of dump resistor protection method for the MgB 2 magnet are also discussed. The results show that the outer edge of magnet is the worst initial quench location, optimized MgB 2 Fe Cu MgB 2 magnet has higher operating security, and the dump resistor protection method is feasible for the small and medium-sized MgB 2 magnet.

Numerical study on the quench propagation in a 1.5 T MgB2MRI magnet design with varied wire compositions

“…where I is the operation current, I c is the critical current for a given magnetic field and temperature, A is the wire's cross sectional area, ρ is the wire's electrical resistivity, and E c is the electrical field criterion. The electrical field criterion is set to 1 μV cm −1 , and the n-value of the wire is set to 30 [37][38][39]. The value of the critical current I c has been provided Hyper Tech Research Inc. and is shown in figure 3(e).…”

“…Previous studies have been made on the stability of superconducting MgB 2 tapes, wires, and their applications, both experimentally [15,27,[29][30][31][32][33]35] and numerically [28,32,[36][37][38][39]. Also, Du et al [39] have investigated the dependence of the temperature rise on the location of the heat disturbance.…”

“…Previous studies have been made on the stability of superconducting MgB 2 tapes, wires, and their applications, both experimentally [15,27,[29][30][31][32][33]35] and numerically [28,32,[36][37][38][39]. Also, Du et al [39] have investigated the dependence of the temperature rise on the location of the heat disturbance. In addition, simulations of the quench propagation and protection for a single coil of a 0.5 T MRI magnet [34] and of the quench propagation of a 1.0 T iron yoke MRI magnet has also been studied [40].…”