3D Macroscopic Model for Fluid Flow and Soot Deposit in Wall Flow Honeycomb DPF 2003-01-0834

This paper presents an original three dimensional model for fluid flow and soot deposition in the overall wall flow honeycomb DPF. First, hot-wire experimental velocity measurements carried out along the DPF outlet cross-section are shown to highlight the flow heterogeneity. Then coupled 1D local momentum and mass balance equations to describe a bundle of channels are proposed and discussed. The model is applied to simulate the loading of a bundle of channels. Two typical cases are considered to illustrate heterogeneity problems: (i) a transverse wall permeability gradient and (ii) the initial blockage of two entrance channels. In this latter case, the heterogeneity effect is found to be confined in the neighbor channels. Finally, a macroscopic form of this set of 1D local equations, obtained using a method of volume averaging applied on a cross-section filter element which consists of several unit elements, is described. First simulations of loading of a square cross-section DPF, having an initial spatial distribution of wall permeability, are performed. Results clearly show the heterogeneity distribution of both the flow and soot deposition through the DPF.