Numerical Study on the Quench Process of Superconducting Solenoid Magnets Protected Using Quench-Back

Quench-back from the mandrel has been widely used in quench protection of superconducting magnets. The rational use of quench-back requires detailed understanding of the heat transfer and electromagnetic process in the magnet during a quench process. A coupled transient thermal-electromagnetic-circuit finite-element model was developed to study the quench process with quench-back. This model sequentially solves two different physics models: one is the thermal physics model, which is used to solve the 3-D temperature field, and the other one is the coupled electromagnetic-circuit physics model, which is used to solve the 2-D axisymmetric electromagnetic field and lumped circuit model. The two models are coupled by applying results from one model as inputs into the other model. The quench process of two solenoid magnets in practical engineering is calculated using this model. Results, such as current, hot-spot temperature, and overvoltage during the quench process, were presented. The effect of quench-back on speeding up the quench process is presented. This can provide a theoretical guidance for application of quench-back in quench protection.