Simulating the Soot Loading in Wall-flow DPF Using a Three-Dimensional Macroscopic Model 2006-01-0264
A three-dimensional macroscopic numerical model is developed to simulate the soot loading process in a typical wall-flow type of diesel particulate filter. The objective of this model is to provide a method for predicting the interaction between the soot loading and the flow distribution. The three-dimensional filter is partitioned into sectors, and each sector represents a group of single DPF channels. The partition of the filter is fine enough to resolve the air flow across the filter. It is assumed that the inlet flow conditions and the soot loadings of channels in each group are the same, and therefore the flow and soot loading in this group can be represented by the global characteristics of each sector. Each sector is further discretized in axial direction and a one-dimensional DPF soot loading model is applied to the sector to compute the velocity distribution and the soot loading in the axial direction for each time step. The permeability distribution is computed from the distribution of the deposited soot, and a porous media model is used with the permeability data to compute the pressure drop across the filter. The three-dimensional macroscopic model is validated with experimental data under uniform inlet boundary conditions. The non-uniform flow distribution is then studied with a generic exhaust pipe geometry.