Helium Pressure rise of Superconducting Super Collider Dipole Magnets Following a Quench

Abstract

Heat transfer to the helium fluid within the magnet windings during and following a quench results in high-pressure gas propagating along the windings. A quasi-steady state approachl can be used for cryostable magnets with a relatively short vent line. For long adiabatic dipole magnets, the maximum pressure rise depends strongly on the magnet length. To determine the helium pressure distribution in the magnet, it is necessary to simultaneously solve the time dependent continuity, momentum, and energy equations for helium in the flow channels, the heat conduction equation in the windings, and the magnet current decay equation. General Dynamics has developed the code QMAG to do this. An early version of the code was applied to a full-length Superconducting Super Collider (SSC) dipole magnet for the extreme case of having helium flow only around the bore tube. Some of the results of that study are reported in this paper. We also report on the code modifications made to model a large cooling tube connected to the bore tube through the regularly spaced gaps in the collar and yoke laminations surrounding the windings. Furthermore, results of a study of a long dipole magnet model are reported in this paper to show the effect of the cooling tube internal flow on the bore tube pressure. The quench pressure results for SSC dipole magnets using the modified code will be published later.