Energetic and CFD Modeling Considerations of Thermal Management

Abstract

An up front CAE coupling of tools is described which provides for routine thermal flow analysis of vehicle powertrain cooling systems for a variety of vehicle shapes and sizes. A family of parametric models is generated using Pro/E which allows for flexible representation of a variety of vehicle classes with accurate thermal flow analyses. The parametric CAD models are morphed to model the important flow features in a relatively complex underhood vehicle model. Some detailed modeling is often added to the generic parametric model for flexibility in modeling important unique details. All tetrahedra meshes are generated automatically from the CAD model using Simmetrix software. High aspect ratio elements are layered near appropriate surfaces for appropriate modeling of shear layers. Templates are used for exporting the mesh and flow simulation parameters to the flow solver, AcuSolve. An unsteady, incompressible air flow with energy equation and Spalart-Almaras turbulence model is used underhood and around the vehicle with simple heat exchanger models and coupled radiation. The flow through grille opening elements is modeled with detailed surfaces and appropriate grid resolution of flow. An adaptation technique using an a posteriori approach is demonstrated. Comparison to test data shows good correlation for a variety of steady and unsteady cases.