A two-dimensional gas-particle two-phase model has been developed based on Eulerian-Eulerian and Eulerian-Lagrangian approach. In this paper, the performance of the Diesel Particulate Filter (DPF) with a thin dense layer on the substrate wall of inlet channel is investigated by coupling microcosmic channel model with filtration model. The velocity field and filtration efficiency of the DPF with thin dense layer was studied and compared with that of the DPF without thin dense layer considering different space velocities, layer permeabilities and particle sizes. Besides, the dynamic of particle deposition inside the porous media of the DPF with layer was simulated by coupling the transient deep-bed filtration model with the DPF microcosmic channel model. The deposition mass distributions inside porous wall of particles with three different sizes were discussed. Results show that the existence of the thin dense layer can bring a much more uniform through-wall velocity along the inlet channel. The presence of the thin dense layer can raise the filtration efficiency of the DPF obviously, especially for particles with medium size. Meanwhile, affected by the existence of the thin dense layer, most particles are collected by the layer and the amount of particles penetrating into the porous wall decreases significantly. The penetration depth into the porous wall of 100 nm particles is much deeper than that of 10 nm and 1000 nm particles.
Keywords Diesel Particulate Filter, inhomogeneous wall structure, gas-solid two-phase flow, velocity field, particle deposition distribution