A methodology for estimating the permeability of a soot deposit in a wall-flow diesel particulate filter

Abstract

An estimation of the realistic permeability of a soot deposit layer accumulated in a wall-flow diesel particulate filter was performed in this study. A unique contribution of this work is that the current methodology is highly applicable to the real-world design and development processes of diesel particulate filters. To conduct baseline simulation, a one-dimensional numerical model describing the behaviours of the exhaust gas and soot within a diesel particulate filter was constructed, employing the well-known single-channel approach. On the basis of this in-house model, the microstructural properties of a soot deposit layer were calibrated by finding the best fit to the measurement data adopted from the open literature. For the optimal applicability of the proposed methodology, the permeability of the deposit is modelled as a variable which depends on the temperature and the average wall velocity, while the porosity is constant. The current model and methodology were validated by comparison with the measurement data for pressure drops through diesel particulate filters. In particular, to boost the practical implementation of the current methodology, a map of the permeability of the soot deposit was created as a function of the operating conditions. In the last part of this study, the pressure drop characteristics through a diesel particulate filter under various operating conditions were examined using an analysis of the breakdown of the individual pressure drop mechanisms.