Simulation of particle-layer rearrangement events in ceramic cross flow filters using Lattice Boltzmann Methods
Cross or wall flow filters are primarily used in the exhaust aftertreatment system of combustion engines. Current law tightenings of emission limits (introduction of a particle number limit and mandatory measurements of real driving emissions) result in increased filtration requirements both in diesel and gasoline-powered vehicles. The expansion of potential application areas leads to the necessity of a deeper examination of wall flow filter behaviour in a process-engineering context, beyond sole engine applications.
During its operation soot is trapped in the filter and frequently oxidized via continuous or periodic regeneration. However, inert components remain and accumulate in the filter, forming specific deposition patterns. Depending on these patterns, an improvement in the filter separation efficiency, an increase in pressure loss and a subsequent increase in energy consumption can be observed. The various patterns are formed by rearrangement events during the regeneration due to the detachment of individual particle agglomerates from the filter surface.
The goal of this project is to investigate the main influencing factors, such as local flow conditions, filter and particle properties, for the rearrangement processes in wall flow filters independently of engine applications. Furthermore the project aims at determining the system sensitivity on the deposition topology employing Lattice Boltzmann fluid flow simulations.