The growing demands on filter elements for automatic transmission fluids in terms of filter lifetime (longer service intervals), cleanliness level of the oil and lower pressure drop represent a great challenge for product designers. In order to ensure good performance of the filters at the widest possible range of operating conditions (e.g. cold start vs. high oil temperature) and facing more restrictive installation space specifications, intense research and development is required for product innovation and optimization.

The fact that the wear in automatic transmissions contains ferromagnetic shares suggests magnetic separation as a way to support the cleaning of the oil by the filter media. However, despite the constraints on the installation space mentioned, this introduces new degrees of freedom for the filter element design. Therefore, a purely empirical approach for the optimization of the device would lead to rather long and costly development cycles. On the other hand, customized simulation tools have proven their worth in accelerating the development of optimized filter elements.

The present work is devoted to the investigation of magnetic separation for cleaning automatic transmission fluids. The experimental methods used for the study and the algorithmic approach for the coupled simulation of fluid flow and particle transport are presented are illustrated by examples and the results are discussed...