Lattice Boltzmann Simulation on Particle Transport and Captured Behaviors in a 3D-Reconstructed Micro Porous DPF 2010-01-0534

In this study, particle transport and captured behaviors in a Diesel Particulate Filter (DPF) was investigated with Lattice Boltzmann Method. LBM calculation was performed to a 3D-reconstructed micro porous DPF substrate, which was obtained by micro-focus 3D X-ray technique.

Simulating advection-diffusion behaviors of diesel particulates in micro porous channel, we adapted a LBM method used for high Peclet number flow, simulating flow conditions in DPFs. We investigated flow behaviors in a wide variety of inlet velocity. LBM simulation has clearly shown that non-dimensional flow field is similar in wide range of flow conditions in the DPF, because flow Reynolds number in the micro porous substrate is sufficiently low, dominated by laminar flow regime. It was also revealed that less than 40% pore channels was responsible for more than 80% volume flux in the porous substrate without particle loading.

We also examined particle deposition behaviors in the porous substrate with LBM simulation. It was indicated that particle diameter and inlet velocity intensively affects deposition behaviors in the DPF, because Brownian motion of particle was highly influenced by particle diameter and thus Peclet number was predominantly determined by particle diameter and inlet velocity in the porous substrate. LBM simulation has shown that small particles around 1nm corresponding to lower Pectler number condition was not able to penetrate the porous substrate due to higher diffusion coefficient and was captured at the front side of the substrate. On the other hand, larger particles matched for higher Peclet number was found to penetrate the porous substrate in early stage of particle loading, suggesting that design and control of micro structures in DPF porous media is of great importance.