Particle accumulation model in 3D reconstructed wall of a catalytic filter validated with time-resolved X-ray tomography

A transient pore-scale model of particle deposit formation in 3D microstructure of a catalytic filter wall is introduced. It predicts location of particle deposits, dynamics of their growth, transition from deep to cake filtration regime as well as the impact on flow field, pressure drop and filtration efficiency. The model is validated against time-resolved X-ray tomography (XRT) data acquired during a filtration experiment. The validated model is then used in transient simulations of the soot filtration process in several different microstructures using cordierite filter substrate with varied Pd/γ-Al ₂O ₃ catalyst distribution. The sample with the coating solely inside the wall pores provides the lowest initial pressure drop but suffers from low clean filtration efficiency and high pressure drop after the cake is formed. The sample with partial on-wall coating achieves not only a higher filtration efficiency but also a lower pressure drop in long-term operation.