As the automotive industry undergoes a transformative shift to battery electric vehicles (BEVs), optimising thermal management systems has become essential to ensure efficient battery cooling, particularly during idle phases when vehicles are charging. In contrast to conventional combustion vehicles, BEVs generate significant heat in stationary states, requiring advanced simulations to model cooling and heat recirculation accurately under zero domain inlet velocity conditions. This thesis investigates the heat recirculation phenomenon in BEVs, with a focus on the Audi A6 e-tron model, to determine whether the cooling system layout promotes recirculation of hot cooler air and, if so, quantify the resulting temperature increase at the cooler inlet. Utilising a combination of steady-state simulations in OpenFOAM and a cooling and climatisation measurement setup, this research applies both incompressible and buoyancy-driven solvers to assess recirculation under steady conditions, constrained by practical computational limitations. In the incompressible simulations, a passive scalar is used to trace the path of hot cooler air originating at the outlet, enabling an indirect approximation of temperature increases by rescaling passive scalar concentrations. Additionally, a steady-state buoyancy-driven simulation incorporating the energy equation further refines the model by accounting for temperature-dependent density variations. Simulation results are validated through the cooling and climatisation measurement setup, and model optimisations progressively enhance accuracy by refining boundary conditions, accounting for thermophysical properties, and stabilising flow behavior. Results reveal that the final optimised models accurately depict the recirculation flow topology at key evaluation sites in the cooling system inlet region, aligning closely with measurement data, thus allowing for a reliable prediction of temperature increases at the cooling system inlet due to recirculation. This model provides engineers with a tool to assess and mitigate recirculation risks across BEV prototypes early in the design process, thereby reducing dependence on physical testing and enabling faster development of more efficient cooling system topologies. The findings underscore the potential for this approach to inform future BEV thermal management innovations and support ongoing advancements in automotive cooling simulations.     «

As the automotive industry undergoes a transformative shift to battery electric vehicles (BEVs), optimising thermal management systems has become essential to ensure efficient battery cooling, particularly during idle phases when vehicles are charging. In contrast to conventional combustion vehicles, BEVs generate significant heat in stationary states, requiring advanced simulations to model cooling and heat recirculation accurately under zero domain inlet velocity conditions. This thesis invest...     »