Roebel-kaapelista valmistetun hiukkaskiihdytinmagneettiprotytyypin lämpömallinnus

Superconductors are a tempting alternative to be used in high-current applications due to their property of lossless current carrying ability. The high material costs and laborious fabrication processes, however, prevent the more common use in different suitable application areas. Presently, several research and development projects use superconductors. One of the applications is the Large Hadron Collider (LHC) particle accelerator in the European Organization for Nuclear Research (CERN). In LHC, superconductor based electromagnets for particle beam steering and focusing are utilized. Superconductors can carry direct current without heat losses only if the current, magnetic field and temperature are below certain boundary, the critical surface. Otherwise the superconductor becomes resistive and heat is generated. This can lead to uncontrollable temperature increasing, quench, in the device and actions are needed in order to prevent damages. One must be prepared for quench by designing an adequate protection system for the device. The design can be aided by simulating heat transfer in the device during quench. The simulations can be time consuming in case of large devices consisting of anisotropic materials, like the magnet's in LHC. However, adequate modelling decisions can significantly reduce the simulation time, while leading to results with sufficient accuracy. This involves identifying the essential interplaying physical phenomena and choosing an appropriate representation for the modelling domain. In this thesis, quench modelling of superconducting magnets is discussed. Moreover, a simulation tool was developed for quench simulations suitable for large superconducting devices. The tool utilizes a novel numerical approach to solve three-dimensional (3-D) heat diffusion in one-dimensional (1-D) modelling domain. To study the capability of the simulation tool, quench analysis was performed for an accelerator magnet prototype. The tool was able to solve the heat transfer during a quench in the magnet in couple of minutes while the same problem utilizing conventional 3-D modelling domain would take several hours even. Furthermore, to study the prospects of utilizing this new approach in quench protection design, comparison with measurement data is needed