A Simplified Approach to Simulate Quench Development in a Superconducting Magnet

Abstract

Cross-sectional 2D models often represent a computationally efficient alternative to full 3D models, when simulating complex multi-physical magnet systems. However, especially for the case of self-protected, superconducting magnets, where the stored energy has to be dissipated within the magnet coils, the thermal diffusion and the quench development in all three dimensions become key aspects. In order to further improve the simulation of transients in 2D models, a new modelling method for simplified quench development along the direction of the transport current is introduced. The original 2D model is hereby utilized for modelling the thermal domain, and the electrical resistance of each turn is scaled by the estimated time-dependent fraction of quenched conductor. Furthermore, the turn to turn quench propagation following the electrical connections is implemented. The proposed approach allows a very computationally efficient and easy-to-implement calculation since the model is effectively two-dimensional while providing a good approximation of the coil resistance development with sufficient accuracy. In order to illustrate the proposed quench-propagation modelling approach, simulations are compared to experimental results for the case of a self-protected, superconducting Nb-Ti dipole magnet. In general, a very good agreement between measurements and simulations was achieved.

Quench Transient Simulation in a Self-Protected Magnet with a 3D Finite-Difference Scheme

“…The same quench transient is simulated with a STEAM-LEDET simulation featuring an enhanced 2D model [35], [36], which accounts for thermal diffusion in the radial and azimuthal directions and approximates the normal zone propagation velocity with a value calculated analytically under adiabatic assumption [37]. This model will be referred to as "2D+1D" in this manuscript.…”