Understanding of the mechanisms that affect flow and pressure drop in porous ceramic diesel particulate filters is important in the design optimization of this class of diesel exhaust after- treatment systems. Furthermore, determination of the parameters involved in the calculation of pressure drop as a function of collected soot mass is important for successful filter loading and regeneration modelling. This paper presents the results of an experimental analysis of pressure drop as a function of the geometric and operating parameters of cordierite and SiC diesel filters. Single- cell filters from cordierite and silicon carbide were prepared to single out any effects from the complex flow processes that take place in a full-sized filter. The product of soot layer permeability and density was experimentally determined by employing a specially designed experimental apparatus. The calculation was supported by a simple computer calculation that is also presented in this paper. The distribution of soot loading inside the channels of a full-sized filter, in various loaded and partially regenerated conditions, was assessed by connecting the apparatus to discharge through selected channels of the filter. The results are shown to improve understanding of the effects of partial regeneration and fuel additive residuals on filter back pressure and flow and soot loading distribution.
Packed bed of spherical particles approach for pressure drop prediction in wall-flow DPFs (diesel particulate filters) under soot loading conditions
