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Prediction of Heat Transfer and Fluid Flow Effects on Entropy Generation in a Monolithic Catalytic Converter Using Large-Eddy Simulation

Li, Yongxiang ; Rico Cortes, Luis Felipe ; Hamel, Hardy ; Nishad, Kaushal ; Biondo, Luigi ; Ries, Florian (2022)
Prediction of Heat Transfer and Fluid Flow Effects on Entropy Generation in a Monolithic Catalytic Converter Using Large-Eddy Simulation.
In: Entropy, 2022, 24 (5)
doi: 10.26083/tuprints-00021283
Article, Secondary publication, Publisher's Version

Abstract

In the present work, heat transfer and fluid flow and their effects on entropy generation in a realistic catalytic converter of a Lada Niva 21214 vehicle are studied using large eddy simulation. At first, the pressure drop over the catalytic converter is measured for dry air at constant temperature (T=298 K), different volumetric flow rates, and extrapolated to large volumetric flow rates for dry air (T=298 K) and for the exhaust gas under realistic engine conditions (T=900 K) using the Darcy–Forchheimer relation. Then, coupled heat and fluid flow phenomena inside the catalytic converter are analyzed for nonreacting isothermal conditions and nonreacting conditions with conjugate heat transfer by using the large-eddy simulation. The predicted pressure drop agrees well with the measured and extrapolated data. Based on the obtained numerical results, the characteristic flow features are identified, namely: the impinging flow with stagnation, recirculation, flow separation and laminarization within the fine ducts of the monolith, which depends on the heat transfer through temperature-dependent thermophysical properties of exhaust gas. Moreover, due to high-velocity gradients at the wall of the narrow ducts in the monolith, entropy production by viscous dissipation is observed predominantly in the monolith region. In contrast, entropy production due to heat transport is relatively small in the monolith region, while it overwhelms viscous dissipation effects in the pipe regions.

Item Type: Article
Erschienen: 2022
Creators: Li, Yongxiang ; Rico Cortes, Luis Felipe ; Hamel, Hardy ; Nishad, Kaushal ; Biondo, Luigi ; Ries, Florian
Type of entry: Secondary publication
Title: Prediction of Heat Transfer and Fluid Flow Effects on Entropy Generation in a Monolithic Catalytic Converter Using Large-Eddy Simulation
Language: English
Date: 2022
Year of primary publication: 2022
Publisher: MDPI
Journal or Publication Title: Entropy
Volume of the journal: 24
Issue Number: 5
Collation: 18 Seiten
DOI: 10.26083/tuprints-00021283
URL / URN: https://tuprints.ulb.tu-darmstadt.de/21283
Corresponding Links:
Origin: Secondary publication DeepGreen
Abstract:

In the present work, heat transfer and fluid flow and their effects on entropy generation in a realistic catalytic converter of a Lada Niva 21214 vehicle are studied using large eddy simulation. At first, the pressure drop over the catalytic converter is measured for dry air at constant temperature (T=298 K), different volumetric flow rates, and extrapolated to large volumetric flow rates for dry air (T=298 K) and for the exhaust gas under realistic engine conditions (T=900 K) using the Darcy–Forchheimer relation. Then, coupled heat and fluid flow phenomena inside the catalytic converter are analyzed for nonreacting isothermal conditions and nonreacting conditions with conjugate heat transfer by using the large-eddy simulation. The predicted pressure drop agrees well with the measured and extrapolated data. Based on the obtained numerical results, the characteristic flow features are identified, namely: the impinging flow with stagnation, recirculation, flow separation and laminarization within the fine ducts of the monolith, which depends on the heat transfer through temperature-dependent thermophysical properties of exhaust gas. Moreover, due to high-velocity gradients at the wall of the narrow ducts in the monolith, entropy production by viscous dissipation is observed predominantly in the monolith region. In contrast, entropy production due to heat transport is relatively small in the monolith region, while it overwhelms viscous dissipation effects in the pipe regions.

Uncontrolled Keywords: catalytic converter, large-eddy simulation, entropy production, Darcy–Forchheimer relation, flow laminarization
Status: Publisher's Version
URN: urn:nbn:de:tuda-tuprints-212837
Classification DDC: 600 Technology, medicine, applied sciences > 600 Technology
600 Technology, medicine, applied sciences > 620 Engineering and machine engineering
Divisions: 16 Department of Mechanical Engineering
16 Department of Mechanical Engineering > Institute for Energy and Power Plant Technology (EKT)
16 Department of Mechanical Engineering > Institute of Reactive Flows and Diagnostics (RSM)
Date Deposited: 06 May 2022 11:13
Last Modified: 09 May 2022 06:23
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