The environment is an increasingly important concern today and no economy is unaffected. This also applies to the friction braking system industry, because of the particles emitted during each braking process. As braking is a complex process, depending on speed, vehicle weight, level of deceleration, as well as environmental conditions such as temperature and humidity which influence the type and nature of the particles emitted, ranging from very fine to coarse. Depending on their nature, these emissions can end up in the environment in the draining water or in the air we breathe. In the literature there are more and more studies about airborne particles; they all show that mainly emitted particles during braking have a distribution which varies with the braking conditions from nano to micro particles. For these reasons, Mercedes Benz AG is looking for suitable methods to understand and analyse the braking emissions and countermeasures to recover the emitted particles. Simulations could support here to provide meaningful information regarding brake dust flow also it can enlarge the view including surrounding components and the full vehicle airflow in the wheel housing. Companies specialized in numerical solutions are also challenged to identify which method would be the most suitable to study the trajectory evolution of these particles after their emission. In this context Altair Engineering proposes the use of the Discrete Element Method (DEM) used in the EDEM software. The DEM method is suitable for studying the behaviour of a very large number of particles interacting with each other and with their environment. The method can be easily coupled with other numerical solutions such as CFD. The numerical characteristics of the problem require a good strategy to solve the equations in an acceptable time. In the presentation, a numerical model representing a vehicle wheel-housing and the braking system will be presented to visualize the evolution of the emission trajectories for certain braking scenario. The aim of these studies is to evaluate if the numerical models are solvable and if their results bring a better understanding of the problems encountered. Eventually a simulation containing a countermeasure will be carried out to estimate the prediction of effectiveness of this measure.

Mercedes-Benz: Ms. Anna Benkowitsh, Mr. Kartik Upadhyay; Altair: Mr. Benjamin Leblanc, Mr. Carles Bosch Padros