The term 'quenching' describes the reversion of an operating superconducting magnet to its normally resistive state. This involves change the conversion of stored magnetic energy to heat. It is usually accompanied by the generation of high temperatures, voltages and stresses, because of the large amount of energy stored by such magnets. Since a magnet may be damaged by a quench, it is important to predict the behaviour of a design in this situation. However, the process involves a complex interaction of electromagnetic and thermal phenomena, so a computer-based simulation is necessary for the analysis of practical magnet designs. It is shown how a quench in a magnet can be modelled using the concept of a ’propagation velocity’ which defines how fast the normal region spreads throughout the magnet. A review of currently-available quench simulation software, much of which uses this approach, is then presented. Modifications are made to one such program, with the aim of widening the range of magnets it can model and improving its usability. This program is shown to give results comparable to those of earlier versions. However, it is still hard to use and further modifications would be difficult. The development of a new program is then described. It makes use of an interactive command shell and has graphical display of input and output. This makes it easy to use, which is important in an engineering environment. The design of the program also allows for considerable flexibility in the description of the magnet and for easy modifications to satisfy future requirements. Several novel features in the analysis of the quench make the program considerably more efficient than its predecessors. A comparison of experimental and predicted results for a simple quench show that good results can be obtained.
Permanent link to this resource: https://doi.org/10.24384/sd3f-v586
Allinson, Mark
School of Engineering, Computing and MathematicsFaculty of Health, Science and Technology
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