Design and validation of an enhanced cooling system model for the High-Luminosity LHC beam dump at CERN

This thesis aims to investigate the thermal performance of the High-Luminosity Large Hadron Collider (HL-LHC) external beam dump cooling system, with a focus on identifying upgrade strategies that are both effective and practically feasible under the increased energy deposition expected during HL operation. A computational frameworkcapable ofmodeling complexmulti-material geometriesand incorporating a temperature-dependent thermal contact resistance (TCC) model was developed in Ansys Fluent. Multiple cooling layouts were evaluated through mesh sensitivity analyses, variations in material properties and flow distribution studies. Key performance indicators included internal energy evolution, energy extraction efficiency and evaluation of thermal-mechanical coupling via contact pressure mapping. Among the explored configurations, the option involving an additional set of cooling ducts placed above the beam dump, referred to as the top ducts configuration, was identified as the most balanced solution. While other configurations involving doubling the inlet massflow achieved the highest total cooling performance, they required substantial modifications to the existing ventilation system. In contrast, the top ducts are expected to reduce peak temperatures in critical regions, enhance thermal contact at the interface between dump components and improve the mechanical stability of internal components during beam dump events. Furthermore, this solution also eliminates the need for air handling unit modifications and simplifies installation within radiologically controlled areas. In conclusion, the top ducts upgrade appears to be the most promising upgrade strategy for HL-LHC beam dump integration, offering a practical compromise between performance and feasibility. This outcome was made possible by the computational framework developed in this work, which can also support dump block monitoring during HL operations and future cooling system benchmarking.