Advances in the science and technology of diesel particulate filter simulation

As diesel emissions regulations are becoming more stringent, diesel particulate filters (DPFs) have become possibly the most important and complex diesel emission control device. A traditional design of experiments approach becomes very time consuming and costly if one wants to address DPF design, system integration, regeneration control strategy optimization and ash ageing assessment, due to the very large number of tests needed. The application of simulation tools provides a promising alternative and hence simulation is increasingly being used for the design of exhaust emission control systems. In a DPF many coupled physico-chemical phenomena occur over widely disparate spatial and temporal scales and the simulation approach should account for and exploit these features. This becomes possible with the introduction of certain defensible assumptions and/or simplifications to arrive at an accurate but computationally tractable DPF simulation approach, for the needs of industrial users. The present chapter summarizes the current state of the science and technology of DPF simulation, from the Aerosol & Particle Technology Laboratory (APTL), addressing consistent and rigorous refinements in a number of areas including: the aerodynamics at the filter and channel inlet, flow, filtration and reaction phenomena at the DPF material microstructure scale, and in coupling/interfacing DPF simulation with three-dimensional (3D) Computational Fluid Dynamics (CFD) codes. Experimental results are cited where appropriate, to re-enforce/validate the points brought forward by the simulation approach.