A Modular Methodology for Complete Vehicle Thermal Management Simulations 2022-01-5064

Vehicle thermal management (VTM) simulations are becoming increasingly important in the development phase of a vehicle. These simulations help in predicting the thermal profiles of critical components over a drive cycle. They are usually done using two methodologies: (1) Solving every aspect of the heat transfer, i.e., convection, radiation, and conduction, in a single solver (Conjugate Heat Transfer) or (2) Simulating convection using a fluid solver and computing the other two mechanisms using a separate thermal solver (Co-simulation). The first method is usually computationally intensive, while the second one isn’t. This is because Co-simulation reduces the load of simulating all heat transfer mechanisms in a single code. This is one of the reasons why the Co-simulation method is widely used in the automotive industry. Traditionally, the methods developed for Co-simulation processes are load case specific. A new methodology for the Co-simulation process is proposed in this study, which can be used across multiple load cases. This is done by adopting a modular approach to the process by splitting it into three modules: (1) Fan, (2) Heat Exchanger, and (3) Exhaust System. For the Fan Module, a new approach has been developed that enables (a) faster simulation times and (b) simulation of dynamic fan speeds. Using the proposed model for the Heat Exchanger, its behavior during Thermal Soak can be accurately simulated. A one-dimensional/three-dimensional (1D/3D) hybrid model has been proposed for the Exhaust Module that combines the advantages of 1D and 3D simulation schemes. A broad spectrum of experiments was chosen to validate the modularity of the methodology. The tests were uphill drive at 60 km/h, Maximum Vehicle Velocity, Thermal Soak, and Stop and Go. The simulations showed encouraging results in comparison to the experiments. This enables the creation of a common methodology for simulating a virtual testing scheme [1].