Modeling and Numerical Calculation of Snow Particles Entering the Air Intake of an Automobile

摘要

A physically based model to predict the amount of snow which is entering the air intake of an automobile is extremely important for the automotive industry. It allows to improve the air intake system in the development state so that new vehicles can be developed in a shorter time. Using an Eulerian/Lagrangian approach within a commercial CFD-software we set up a model and calculated the snow ingress into an air intake of an automobile. In our numerical investigations we considered different particle shapes when calculating the drag coefficient, different coefficients of restitution and different particle sizes. Furthermore two-way coupling was considered. To obtain key parameters for the simulation, we measured the size of snow particles in the Daimler climatic wind tunnel in Sindelfingen by using a microscope and a measuring device from Malvern. Besides we used mechanical snow traps to determine the snow mass flux in the climatic wind tunnel and on a test area in Sweden. The numerical results show that especially the wall-impact behavior, the particle size and the particle shape can have a significant influence on the snow ingress into the air intake. Because there are currently uncertain parameters in describing the wall-impact behavior and the distribution of the particle shape on the road further investigations are needed to predict the exact amount of snow particles entering the air intake of an automobile.