Pore-scale filtration model for coated catalytic filters in automotive exhaust gas aftertreatment

• Published in: Chemical engineering science 2020-11, Vol.226, p.115854, Article 115854
• Main Authors: Plachá, Marie, Kočí, Petr, Isoz, Martin, Svoboda, Miloš, Price, Emily, Thompsett, David, Kallis, Kyriakos, Tsolakis, Athanasios
• Format: Article
• Language: English
• Subjects: Automotive exhaust gas aftertreatment; Catalyst; CFD; Filtration; Mathematical modeling; Particulate filter
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2020.115854

•Catalytic filters with in-wall, on-wall and combined washcoat distribution are compared.•Pore-scale filtration model is developed for 3D microstructures obtained from XRT.•Filtration efficiency is predicted depending on particle size, flow rate and coating distribution.•Model predictions are compared to experimental data from engine test bench.•Partial on-wall coating significantly improves filtration performance. In this paper we explore the impact of catalyst distribution on the filtration efficiency of automotive exhaust gas filters (GPF and DPF). The structure of filter wall is reconstructed from 3D X-ray tomography (XRT), including spatial distribution of catalytic material. The filtration process is simulated by a custom solver developed and implemented in OpenFOAM using Lagrangian approach for soot particles. GPF samples based on a cordierite substrate are examined with the same amount but different distribution of washcoat, ranging from in-wall to on-wall arrangement. Clean filtration efficiencies are predicted depending on gas velocity and particle size. Brownian motion strongly improves the filtration of particles smaller than 50 nm. On-wall catalyst layer significantly increases the clean filtration efficiency. The obtained results are compared to experimental data from engine test bench.