INVESTIGATION OF QUENCH PRESSURE TRANSIENTS IN THE LHC SUPERCONDUCTING MAGNETS

In case of resistive transition of a LHC superconducting magnet (''quench''), the stored energy is dissipated in the winding within a few tenths of a second. A fraction of this energy is transferred to the helium inside the windings and around the beam tubes, causing expansion and axial flow. This results in a fast pressure peak (several MPa) at the midlength of the magnet. We present a one-dimensional thermo-hydraulic model aiming at simulation of the quench pressure peak and study the influence of geometrical parameters, such as magnet length and beam pipe diameter. Results of simulations are compared to measurements performed on a short model and on a quasi-full scale prototype of the LHC dipoles.