Throat Unit Collector Modeling for Gasoline Particulate Filter Performance
Pengze Yang, Texas A&M University
The wide application of Gasoline Direct Injection (GDI) engines and the continuously more stringent Particulate Matter (PM) and Particulate Number (PN) regulations make Gasoline Particulate Filters (GPFs) with high filtration efficiency and low pressure drop highly desirable. However, design of these filters is more challenging as compared to their diesel counterparts and research is ongoing to understand how GPF wall microstructure impacts its performance. Previous work has demonstrated that CFD studies are effective ways to investigate these filters. In particular, our previous 2-D CFD study elucidated the pore size and pore size distribution effects on GPF filtration efficiency and pressure drop. The “throat unit collector” model developed in this study furthers this work in order to characterize the GPF wall microstructure more precisely. Throat unit collectors with different diameter ratios were created and run in ANSYS FLUENT to calculate the size-dependent filtration efficiency. The simulation results indicated a non-linear change of single collector efficiency as the efficiency first decreased and then increased with a decreasing throat unit collector diameter ratio. The simulation results also showed the total wall filtration efficiency increased as the throat unit collector diameter ratio decreased. The throat unit collector model was also used to simulate the wall filtration efficiency change during particulates loading. The decrease of pore size in throat unit collector was to mimic the pore bridging process during loading.