Simulation of Particle-Agglomerate Transport in a Particle Filter using Lattice Boltzmann Methods

Wall-flow filters are used as particle filters in the exhaust gas after treatment of combustion engines. Soot is deposited in the filter and removed from it by regeneration through oxidation. However, an inert portion (ash) remains in the filter and forms different deposition patterns. Those patterns affect the separation efficiency as well as the overall pressure drop. The formation of deposition patterns is caused by rearrangement processes during regeneration, which result from the break-up of the particle layer as well as the resuspension and transport of individual agglomerates. With the help of the Homogenized Lattice Boltzmann Method (HLBM), resolved particle simulations are carried out within the framework of the open source software OpenLB. This allows the forces acting on the agglomerates to be determined and detachment and transport processes to be modelled. The focus of the present work is on a detailed investigation of the flow-induced transport of individual particle-agglomerates.