Simulation of particulate matter structure detachment from surfaces of wall-flow filters applying lattice Boltzmann methods

Abstract

Wall-flow particulate filters are used for particulate matter removal from exhaust in aftertreatment systems of combustion engines. Inside these filters, the gas flow passes through a porous wall between oppositely arranged inlet and outlet channels. Due to continuously introduced solid material, the filters have to be regenerated resulting in a breakup of continuous layers deposited on the walls into individual fragments. Those can re-arrange and impact operational filter performance significantly.This process is governed by the interaction of hydrodynamic and adhesive forces, which can only be accurately modelled by taking the surfaces of individual layer fragments into account. With surface resolved simulations, those forces can be evaluated and detailed investigations of detachment and rearrangement processes can be performed.The present work, therefore, presents a lattice Boltzmann approach for the simulation of particulate matter structure detachment capable of capturing the time dependent evolution of the flow field during the filter’s regeneration. First, a numerical model of a single wall-flow filter channel is presented and its validity for the particle-free case is substantiated by showing super-linear grid convergence and good agreement with a reference solution. Then, the model’s capability is shown by applying it to the transient simulation of the rearrangement process.