Simulation of deep-bed filtration of a gasoline particulate filter with inhomogeneous wall structure under different particle size distributions

In order to describe the microstructure of the porous wall of a gasoline particulate filter (GPF), a pore size distribution based on a probability density function (PDF) and a non-uniform porosity distribution are introduced. The dynamic process of deep-bed filtration in GPF with inhomogeneous wall structure is studied, considering different particle size distributions (PSDs). The results show that most of the particles are captured in the top region of the porous wall, in which the porosity and permeability reduce more obviously during dynamic filtration, and the bottom of the porous wall contributes little to the overall filtration. As time increases, the filtration efficiency of the porous wall for each particle size increases, and the most penetrating particle’s diameter becomes smaller gradually. The dynamic evolution of characteristic parameters of the porous wall, the most efficient filtration region, the pressure drop and the duration of deep-bed filtration are strongly influenced by PSD. This research illustrates the necessity to consider difference of PSDs when working on the filtration process of GPFs.