Simulation on Flow and Heat Transfer in Diesel Particulate Filter

To reduce particulate matters including soot, a diesel particulate filter (DPF) has been developed for the after-treatment of exhaust gas. Since the filter is plugged with particles that would cause an increase of filter back-pressure, filter regeneration process is needed. However, there is not enough data on the phenomena in DPF because there are many difficulties in measurements. In this study, the flow in DPF is simulated by the lattice Boltzmann method. To focus on a real filter, the inner structure of the filter is scanned by a 3D X-ray computed tomography technique. By conducting tomography-assisted simulation, the local velocity and pressure distributions in the filter can be visualized, which is hardly obtained by measurements. Results show that, even in cold flow, the complex flow pattern is observed due to the nonuniformity of pore structure inside the filter. Based on the flow characteristics in the range of 0.2–20 m/s, simulation results show a good agreement with the empirical equation of Ergun equation. In the combustion simulation, the time-dependent temperature field inside the filter is visualized. As the temperature of inflow gas is increased, the filter regeneration process is promoted.