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Walter R, Neumann J, Velroyen A, Hinrichsen O. Applying 3D X-ray Microscopy to Model Coated Gasoline Particulate Filters under Practical Driving Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:12014-12023. [PMID: 35994629 DOI: 10.1021/acs.est.2c01244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recent progress in 3D X-ray microscopy allows the analysis of coated gasoline particulate filters on a detailed pore-scale level. However, derivable detailed three-dimensional models for filter simulation are not applicable under transient driving conditions of automotive aftertreatment systems due to their inherent complexity. Here, we present a novel concept to utilize highly resolved 3D X-ray microscopy scans and their quantitative analysis for a macroscopic model of coated gasoline particulate filters intended to be applied in a driving cycle. A previously developed filtration model build on a 1D + 1D flow model on the channel scale of a filter is utilized. Accompanying measurements conducted on a dynamic engine test bench serve as validation for pressure drop and filtration characteristics. With the determined properties from 3D X-ray microscopy, the macroscopic model successfully replicates the measurements. Regarding the filter coating, the reduced porosity and a decrease of medium sized pores relative to an uncoated substrate reduce the filtration efficiency under steady-state as well as transient conditions.
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Affiliation(s)
- Raimund Walter
- Development Powertrain, BMW Group, Schleißzheimer Str. 422, 80937 Munich, Germany
- Department of Chemistry, Technical University of Munich, Lichtenbergstraßze 4, 85748 Garching near Munich, Germany
- Catalysis Research Center, Technical University of Munich, Ernst-Otto-Fischer-Straßze 1, 85748 Garching near Munich, Germany
| | - Jens Neumann
- Development Powertrain, BMW Group, Schleißzheimer Str. 422, 80937 Munich, Germany
| | - Astrid Velroyen
- Technology Material and Process Analysis, BMW Group, Hufelandstr. 5, 80937 Munich, Germany
| | - Olaf Hinrichsen
- Department of Chemistry, Technical University of Munich, Lichtenbergstraßze 4, 85748 Garching near Munich, Germany
- Catalysis Research Center, Technical University of Munich, Ernst-Otto-Fischer-Straßze 1, 85748 Garching near Munich, Germany
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Lyu Q, Ou Q, Chen W, Wang Y, Chang C, Li Y, Che D, Pui DY. Impacts of catalyst coating on the filtration performance of catalyzed wall-flow filters: From the viewpoint of microstructure. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2021.120417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Walter R, Neumann J, Hinrichsen O. Modeling the Catalytic Performance of Coated Gasoline Particulate Filters under Various Operating Conditions. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c03631] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Raimund Walter
- BMW Group, Development Powertrain, Schleißheimer 422, D-80937 Munich, Germany
- Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching near Munich, Germany
- Catalysis Research Center, Technical University of Munich, Ernst-Otto-Fischer-Straße 1, D-85748 Garching near Munich, Germany
| | - Jens Neumann
- BMW Group, Development Powertrain, Schleißheimer 422, D-80937 Munich, Germany
| | - Olaf Hinrichsen
- Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching near Munich, Germany
- Catalysis Research Center, Technical University of Munich, Ernst-Otto-Fischer-Straße 1, D-85748 Garching near Munich, Germany
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Full-Field Comparison of MRV and CFD of Gas Flow through Regular Catalytic Monolithic Structures. Processes (Basel) 2021. [DOI: 10.3390/pr9030566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Understanding the influence of gas flow maldistribution in honeycombs can be beneficial for the process design in various technical applications. Although recent studies have investigated the effect of maldistribution by comparing the results of numerical simulations with experimental measurements, an exhaustive 3D full-field comparison is still lacking. Such full-field comparisons are required to identify and eliminate possible limitations of numerical and experimental tools. For that purpose, spatially resolved flow patterns were simulated by computational fluid dynamics (CFD) and measured experimentally by non-invasive NMR velocimetry (MRV). While the latter might suffer from a misinterpretation of artefacts, the reliability of CFD is linked to correctly chosen boundary conditions. Here, a full-field numerical and experimental analysis of the gas flow within catalytic honeycombs is presented. The velocity field of thermally polarized methane gas was measured in a regular 3D-printed honeycomb and a commercial monolith using an optimized MRV pulse sequence to enhance the obtained signal-to-noise ratio. A second pulse sequence was used to show local flow propagators along the axial and radial direction of the honeycomb to quantify the contribution of diffusion to mass transport. A quantitative comparison of the axially averaged convective flow as determined by MRV and CFD shows a very good matching with an agreement of ±5% and 10% for printed and commercial samples, respectively. The impact of maldistribution on the gas flow pattern can be observed in both simulation and experiments, confirming the existence of an entrance effect. Gas displacement measurements, however, revealed that diffusive interchannel transport can also contribute to maldistribution, as was shown for the commercial sample. The good agreement between the simulation and experiments underpins the reliability of both methods for studying gas hydrodynamics within opaque monolith structures.
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Leskovjan M, Němec J, Plachá M, Kočí P, Isoz M, Svoboda M, Novák V, Price E, Thompsett D. Multiscale Modeling and Analysis of Pressure Drop Contributions in Catalytic Filters. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c05362] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martin Leskovjan
- University of Chemistry and Technology, Prague, Department of Chemical Engineering, Technická 5, Praha 166 28, Czech Republic
| | - Jan Němec
- University of Chemistry and Technology, Prague, Department of Chemical Engineering, Technická 5, Praha 166 28, Czech Republic
| | - Marie Plachá
- University of Chemistry and Technology, Prague, Department of Chemical Engineering, Technická 5, Praha 166 28, Czech Republic
| | - Petr Kočí
- University of Chemistry and Technology, Prague, Department of Chemical Engineering, Technická 5, Praha 166 28, Czech Republic
- New Technologies Research Centre, University of West Bohemia, Univerzitní 8, Pilsen 306 14, Czech Republic
| | - Martin Isoz
- University of Chemistry and Technology, Prague, Department of Mathematics, Technická 5, Praha 166 28, Czech Republic
- Czech Academy of Sciences, Institute of Thermomechanics, Dolejškova 5, Praha 182 00, Czech Republic
| | - Miloš Svoboda
- New Technologies Research Centre, University of West Bohemia, Univerzitní 8, Pilsen 306 14, Czech Republic
| | - Vladimír Novák
- Swiss Light Source, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Emily Price
- Johnson Matthey Technology Centre, Blounts Court Road, Sonning Common, Reading RG4 9NH, United Kingdom
| | - David Thompsett
- Johnson Matthey Technology Centre, Blounts Court Road, Sonning Common, Reading RG4 9NH, United Kingdom
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Walter R, Neumann J, Hinrichsen O. Extended Model for Filtration in Gasoline Particulate Filters under Practical Driving Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:9285-9294. [PMID: 32598146 DOI: 10.1021/acs.est.0c02487] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In order to reliably predict the particle number filtration of gasoline particulate filters (GPF) under practical driving conditions, an extension to established filtration models is developed. For the validation of this approach and in order to close a gap of available measurement data at high space velocity in the literature, the particle-size-resolved fresh filtration efficiency of seven different cordierite filters is determined experimentally. Moreover, the experiments on a dynamic engine test bench focus on the impact of the pore-size distribution and the filter wall thickness under steady-state as well as transient, cold-start conditions. In order to model all trends observed, a new correlation for the particle collection due to inertial deposition is proposed and embedded in a heterogeneous multiscale model framework for a GPF. The presented approach can predict all trends observed in the measurements, including a stabilization of the filtration efficiency with increasing space velocities above a certain level. A comparison of several modeling approaches reveals the partly different behaviors at varying space velocities for the here presented model as well as for established filtration models.
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Affiliation(s)
- Raimund Walter
- Development Powertrain, BMW Group, Hufelandstraße 4, D-80788 Munich, Germany
- Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching, Germany
| | - Jens Neumann
- Development Powertrain, BMW Group, Hufelandstraße 4, D-80788 Munich, Germany
| | - Olaf Hinrichsen
- Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching, Germany
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Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9245384] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Late fuel post-injections are the most usual strategy to reach high exhaust temperature for the active regeneration of diesel particulate filters. However, it is important to optimise these strategies in order to mitigate their negative effect on the engine fuel consumption. This work aims at understanding the influence of the post-injection parameters, such as its start of injection and its fuel quantity, on the duration of the regeneration event and the fuel consumption along it. For this purpose, a set of computational models are employed to figure out in a holistic way the involved phenomena in the interaction between the engine and the exhaust gas aftertreatment system. Firstly, an engine model is implemented to evaluate the effect of the late fuel post-injection pattern on the gas properties at the exhaust aftertreatment system inlet in different steady-state operating conditions. These are selected to provide representative boundary conditions of the exhaust gas flow concerning dwell time, exhaust temperature and O 2 concentration. In this way, the results are later applied to the analysis of the diesel oxidation catalyst and wall-flow particulate filter responses. The dependence of the diesel particulate filter (DPF) inlet temperature is discussed based on the efficiency of each post-injection strategy to increase the exhaust gas temperature. Next, the influence on the dynamics of the regeneration of the post-injection parameters through the change in gas temperature and O 2 concentration is finally studied distinguishing the pre-heating, maximum reactivity and late soot oxidation stages as well as the required fuel consumption to complete the regeneration process.
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