1D Thermo-Fluid Dynamic Modeling of Reacting Flows inside Three-Way Catalytic Converters

Montenegro, Gianluca; Onorati, Angelo

doi:10.4271/2009-01-1510

Cited by 18 publications

(4 citation statements)

References 13 publications

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“…In this context, the flow resistance component R g is typically modeled by the Hagen-Poiseuille theory for laminar flows [14] or exploiting the Churchill [15] or Darcy-Forchheimer correlations. The inter-phase heat and mass transfer terms (Equations (1) and ( 2)) are typically computed resorting to Hawthorn correlations [16,17] for the estimation of Nusselt and Sherwood numbers as a function of Reynolds, Prandtl, and Schmidt numbers:…”

Section: Multi-region Frameworkmentioning

confidence: 99%

CFD Investigation of an Innovative Additive Manufactured POCS Substrate as Electrical Heated Solution for After-Treatment Systems

et al. 2023

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In the last decade, additive manufacturing (AM) techniques have been progressively applied to the manufacturing of many mechanical components. Compared to traditional techniques, this technology is characterized by disruptive potential in terms of the complexity of the objects that can be produced. This opens new frontiers in terms of design flexibility, making it possible to create new components with optimized performances in terms of mechanical properties and weight. In this work, the focus is on a specific field of application: the development of novel porous media structures which can be the basis of advanced after-treatment systems for internal combustion engines. In particular, the possibility to design periodic open cellular structures (POCSs) that can be applied as catalytic substrates opens new perspectives in terms of flexibility and integrated functionalities. The present study investigates an innovative solution where the catalytic substrates are located in the pipes of the exhaust manifolds of a high-performance engine. A preliminary characterization of the pressure drop induced by the POCS structure is carried out, with a particular focus on the impact of the backpressure on the engine performances. Moreover, each POCS integrates an electrical circuit which is used to promote the heating of the device, with beneficial effects on the light-off of the catalytic reactions. An advanced CFD model is applied to evaluate the potential of the solution, comparing the pollutant conversion with that of the baseline configuration equipped with a standard after-treatment system solution.

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Section: Multi-region Frameworkmentioning

confidence: 99%

CFD Investigation of an Innovative Additive Manufactured POCS Substrate as Electrical Heated Solution for After-Treatment Systems

et al. 2023

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“…where Hawthorn correlation has been introduced in order to estimate Nusselt and Sherwood numbers as a function of Reynolds, Prantdl and Schmidt [14,15].…”

Section: Models For Coupling Between Regionsmentioning

confidence: 99%

Numerical Assessment of an After-Treatment System Equipped with a Burner to Speed-Up the Light-Off during Engine Cold Start

Torre¹,

Barillari²,

Montenegro³

et al. 2021

SAE Technical Paper Series

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In the next years, the upcoming emission legislations are expected to introduce further restrictions on the admittable level of pollutants from vehicles measured on homologation cycles and real drive tests. In this context, the strict control of pollutant emissions at the cold start will become a crucial point to comply with the new regulation standards. This will necessarily require the implementation of novel strategies to speed-up the light-off of the reactions occurring in the after-treatment system, since the cold start conditions are the most critical one for cumulative emissions. Among the different possible technological solutions, this paper focuses on the evaluation of the potential of a burner system, which is activated before the engine start. The hypothetical burner exploits the lean combustion of an air-gasoline mixture to generate a high temperature gas stream which is directed to the catalyst section promoting a fast heating of the substrate. In this work, an experimental test bench has been adopted to characterize the thermal transient of the after-treatment system when the burner-like system is activated, monitoring the temperature of the gas flow and the temperature of the metallic walls at different locations. Moreover, a CFD model has been developed to investigate the light-off of the reactions during the initial operation of the burner and the subsequent start of the engine. The model, developed on the basis of the OpenFOAM code, resorts to a multi-region approach, where different meshes are employed to describe the fluid domain and the solid regions, namely the catalytic porous substrates and the metallic walls constituting pipes and canning. Specific submodels are implemented to consider flow resistance, heat transfer, mass transfer and catalytic reactions occurring in the catalyst region. The CFD framework has been initially validated on the experimental data acquired on the test bench. The methodology has been then applied to the preliminary analysis of the catalyst light-off at engine cold start, considering a full exhaust line equipped with burner-like system.

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“…When starting from cold conditions in the New European Driving Cycle, there is a warm-up period of 200 s in a standard test duration of 1200 s . In the early stage of the cold start, water vapor in the exhaust gas condenses inside the catalytic converter, which hinders the temperature increase and results in a longer warm-up period. − De Angelis et al used subsecond X-ray tomography to demonstrate the rapid nature of water evaporation in catalytic converters, which occurred within approximately 3 s after the evaporation of the excess water surrounding these samples . The condensed water evaporation was presumed to be initiated from macroscopic cracks and subsequently from the interior of the pores.…”

Section: Introductionmentioning

confidence: 99%

In Situ Small-Angle Neutron Scattering Analysis of Water Evaporation from Porous Exhaust-Gas-Catalyst Supports

Yoshimune

Kato

Harada

2022

ACS Appl. Mater. Interfaces

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Porous media as catalyst supports are key to developing automotive exhaust purification systems. In particular, the water content of these porous media is attracting research attention because catalyst supports containing condensed water vapor at the early stage of cold start require a longer warm-up period. In this regard, water isotherms and evaporation in porous Al 2 O 3 were investigated in this study using in situ small-angle neutron scattering (SANS) experiments. Unlike conventional evaluation methods, such as weighing and X-ray tomography, SANS distinguishes water in the primary and secondary pores using a contrast-matching method. Time-resolved measurements showed that water started to evaporate from the secondary pores in tens of seconds and subsequently from the primary pores in a hundred seconds. Exhaustive experiments conducted using nine alumina-based samples revealed that the drying rate depended on the secondary pore size of the porous Al 2 O 3 . The proposed approach can enable the evaluation of controlling factors to additionally optimize the performance of automotive exhaust gas catalysts, especially during cold start.

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1D Thermo-Fluid Dynamic Modeling of Reacting Flows inside Three-Way Catalytic Converters

Cited by 18 publications

References 13 publications

CFD Investigation of an Innovative Additive Manufactured POCS Substrate as Electrical Heated Solution for After-Treatment Systems

CFD Investigation of an Innovative Additive Manufactured POCS Substrate as Electrical Heated Solution for After-Treatment Systems

Numerical Assessment of an After-Treatment System Equipped with a Burner to Speed-Up the Light-Off during Engine Cold Start

In Situ Small-Angle Neutron Scattering Analysis of Water Evaporation from Porous Exhaust-Gas-Catalyst Supports

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