Multiphysics Modelling of the LHC Individually Powered Quadrupole Superconducting Circuits

This thesis describes the generation and the validation of the models of LHC Individually-Powered Quadrupole (IPQ) superconducting circuits. These circuits include magnets made of Nb-Ti superconductor, working at a temperature of 1.9 K or 4.5 K, and with a nominal current of 3610 A or 5390 A. They are protected against the effects of a quench by quench heaters. The purpose of this work is to generate the electrical circuit using STEAM-SING and the electro thermal model using STEAM-LEDET, and validate them with the tests performed during the LHC Hardware Commissioning. Furthermore, the validated circuit and magnet models can be run together in a cooperative simulation using STEAM-COSIM, which can exchange information between several models in order to obtain a consistent solution. For the validation different types of transients have been used, in particular, Slow Power Abort for the validation of the electrical circuit model and Fast Power Abort for the validation of the electro-thermal model and the co-simulation. The validated models are now part of the library of LHC superconducting circuit models developed with the STEAM framework.