Wall-Flow Particulate Filters With Asymmetric and Variable Cell Geometry
Athanasios Konstandopoulos, APT Lab, CPERI/CERTH
Asymmetric and Variable Cell geometry Diesel Particulate Filters (DPFs) hold high promise, to provide higher filtration area, lower pressure drop and ash storage capacity. In the present work we present an approach for designing and optimizing such DPFs by providing a quantitative description of the flow and deposition of soot in their structure. Soot deposit growth dynamics in asymmetric and variable cell geometry DPFs is studied computationally, primary and secondary flows over the inlet channels cross-sectional perimeters are analyzed and their interactions are elucidated. The result is a rational description of the observed growth of soot deposits, as the flow readjusts to transport the soot particles along the path of least resistance (which is not necessarily the shortest geometric path between the inlet and outlet channel, i.e. the wall thickness). The theoretical description is in excellent agreement with experimental data obtained with two different families of such DPFs operated in the exhaust of a diesel engine and can be employed to design new DPF configurations with substantially lower pressure drop than existing designs.