Simulating the Flow and Soot Loading in Wall- Flow DPF Using a Two-Dimensional Mesoscopic Model

A two-dimensional mesoscopic approach has been developed to investigate the flow and soot loading in the micro-channels of diesel particulate filter. Soot particle size examined is in the range of 10 nm to 10 μm. The flow is solved by an incompressible lattice Boltzmann model and the transport of solid particle is described in a Lagrangian frame of reference by cell automation probabilistic model. The lattice Boltzmann-cell automation probabilistic model (LB-CA model) is validated with the results of previous studies. The heterogeneous porous wall of DPF is generated by quartet structure generation set (QSGS). The effects of porous wall on the pressure field and velocity field are investigated. The distribution and deposition of soot particles with different sizes in clean channels are simulated. The dynamic evolution of solid boundary in soot particle capture process is investigated and the effects of the deposited soot particles on flow field are evaluated. The results show that the porous structure significantly affects the distribution of velocity field and pressure field in the channel. A clear granular segregation phenomenon appears in the inlet channel for 1 μm , 100 nm particles. There is no clear parabolic boundary between particle swarms and flow field for 10 nm particles. All particles in the simulation preferentially deposit at the end of the channel (0.8 < X/L < 1). All particles have almost the same particle deposition probability at the middle part of the channel (0.3 < X/L < 0.8). Particles of 10 nm are more likely to deposit at the front of the channel (X/L < 0.3). The distribution of deposition probability follows the distribution of the through-wall velocity for all particles. The solid boundary made of the captured soot particles of 1 μm appears first in the rear part of the inlet channel and then moves gradually to the middle part of the inlet channel. The effects of the deposited soot particles of 1 μm on flow field lie at the rear of the inlet channel.