Development and validation of a simulation tool for next generation detector cooling systems

Carbon dioxide (CO$_2$) has emerged as a very suitable refrigerant for Tracker cooling applications in high-energy physics. It has been successfully implemented in a two-phase pumped-loop cycle on three experiments at CERN. CO$_2$-based cooling systems will continue to be used for the next generation of Silicon detectors at CERN. These next generation detectors will be much larger and will be operated at much lower temperatures than those considered so far and thus the cooling systems will need to be correspondingly upgraded. The numerical simulation tool developed at CERN to inform such an upgrade is presented here, together with the results of its validation carried out using experimental data generated with a purpose-built test setup.