Aerodynamics and thermal management of road vehicles
Abstract
The energy efficiency of road vehicles is central for the creation of a sustainable and modern society. In this effort, the aerodynamic drag and the thermal efficiency of systems and components are fundamental parameters to optimize since they have a direct influence in the green gas house emissions and the drive range in the case of Battery Electric Vehicles (BEVs). The flow around road vehicles is very complex due to the presence of three-dimensional, unsteady flow structures that are linked to regions prone to separation. These separation prone regions typically have a very large (negative) effect on the drag and thermal behaviour of vehicles.
The Road Vehicle Aerodynamics & Thermal Management Group (RVAD) at Chalmers has extensive experience with these types of flows and works in close collaboration with the Swedish automotive industry through various research projects. To maintain, and further develop the group’s international competitiveness, availability to large computational resources is critical. The simulations conducted by the group are based on the use of Delayed Detached Eddy Simulation (DDES) on detailed geometries, often in full-scale, and at realistic Reynolds numbers. These computations require several seconds of simulation time for meaningful averaging of the flow field. In addition, large mesh sizes are needed to adequately resolve the near wall flow, making the total process very computationally demanding. Over the past years, our research projects have used approximately 700 kCPUh/month. This has been possible using our allocation with the SNIC and a temporary availability of resources at our main industrial partner.
In aerodynamics, the group’s focus has been in two major areas of potential drag reduction: (1) the vehicle’s rear wake, and (2) the flow around wheels. We also work on a broader perspective and study solutions for future transportation systems, such as platooning, high-speed and crosswind driving stabilities. For the past years, the group has significantly increased its research portfolio in the area of thermal management (TM), particularly for Battery Electric Vehicles (BEVs). The need for increase knowledge in this area is a clear signal we receive from the automotive industry. We work today on 3 large TM projects. The group collaborates with Volvo Cars, Volvo AB, Scania, and CEVT. Our activities are financially supported by the Swedish automotive industry, the Swedish Energy Agency and the Chalmers Areas of Advance: Transport and Energy.
