Testing and modeling of air elimination in automotive cooling system

Johan Forsgren, David Winqvist (Chalmers University of Technology)

CHALLENGE -  The emerging electrification and the increased complexity of vehicles brings high demands on temperature regulation and the cooling system. Studies have shown that entrapped air in the cooling system does have negative effects on its performance and also causes deterioration of its components. In order to relieve the system from this unfavorable air, different kinds of separators are commonly used.

SOLUTION - This study investigated the use of cyclone separators in a vehicle cooling system. The aim of the project was to increase the knowledge regarding separators and provide Volvo Cars Corporation with a design suggestion. Simplified lab experiments on a transparent separator were used to validate a steady state, Eulerian-Eulerian CFD model in the computational software STAR-CCM+. The phases were evaluated using the Reynolds Stress Turbulence and turbulence response models. The computational model was utilized in combination with a parametric CAD-model to evaluate various design aspects which were found relevant based on a literature survey. A design of experiments was conducted and using the optimization toolbox of the commercial software modeFRONTIER, a final design suggestion was presented. A 3D-printed model was used for verification of the final design in the lab test rig.

BENEFITS - The thesis has provided relevant information regarding different design parameters’ effect on separation efficiency, pressure drop and volume of the separator. The work has also shown the significance of the flow structures and bubble size entering the separator. Finally, the optimized design of the separator shows clear performance improvements in comparison to the reference model.