Simulation of quench behaviour of the recombination dipole magnet for the LHC High Luminosity upgrade

Superconducting magnets are one of the key components of particle accelerators. Their safety and integrity as well as understanding their behavior is of great interest. In order to simulate the complex transients occurring in superconducting magnet circuits, the STEAM framework, which consists of dedicated software tools and model libraries, was developed at CERN. To enhance repeatability, consistency, traceability and versioning the STEAM framework was recently restructured into an interconnected Python framework called STEAM-SDK. This thesis describes the validation process of the recombination dipole magnet (MBRD) model, which will be part of the High Luminosity LHC, using the STEAM-SDK structure. A LEDET 2D electro-magnetic and thermal model is able to simulate quench transients at high current very well. To improve the model at low current the quench propagation in the third dimension can be included in LEDET. To capture the quench transient of a quench heater protected magnet at all current levels a consecutive simulation process, consisting of LEDET and PyBBQ is proposed. By modelling the longitudinal quench propagation in the coil turns in thermal contact to quench heaters with PyBBQ it is possible to account for cooling effects occurring due to superfluid helium. The PyBBQ output can be used as initial value for the propagation in the third dimension in LEDET. In this thesis a generalized function for quench heater protected magnets is developed and implemented in STEAM-SDK structuring the simulation process and thereby allowing in the future efficient and fast simulation and model validation against experimental results. The validated model of MBRD is used to predict key parameters in different operation scenarios and failure cases. On the basis of these results an alternative protection to the original baseline is proposed aiming for a significant reduction of hot-spot temperature and voltage to ground.