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Simulation of a thermoelectric gas sensor that determines hydrocarbon concentrations in exhausts and the light-off temperature of catalyst materials

Titelangaben

Ritter, Thomas ; Wiegärtner, Sven ; Hagen, Gunter ; Moos, Ralf:
Simulation of a thermoelectric gas sensor that determines hydrocarbon concentrations in exhausts and the light-off temperature of catalyst materials.
In: Journal of Sensors and Sensor Systems. Bd. 6 (22 Dezember 2017) . - S. 395-405.
ISSN 2194-878X
DOI: 10.5194/jsss-6-395-2017

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Link zum Volltext (externe URL): Volltext

Abstract

Catalyst materials can be characterized with a thermoelectric gas sensor. Screen-printed thermopiles measure the temperature difference between an inert part of the planar sensor and a part that is coated with the catalyst material to be analyzed. If the overall sensor temperature is modulated, the catalytic activity of the material can be varied. Exothermic reactions that occur at the catalyst layer cause a temperature increase that can then be measured as a sensor voltage due to the Seebeck coefficient of the thermopiles. This mechanism can also be employed at stationary conditions at constant sensor temperature to measure gas concentrations. Then, the sensor signal changes linearly with the analyte concentration. Many variables influence the sensing performance, for example, the offset voltage due to asymmetric inflow and the resulting inhomogeneous temperature distributions are an issue. For even better understanding of the whole sensing principle, it is simulated in this study by a 3-D finite element model. By coupling all influencing physical effects (fluid flow, gas diffusion, heat transfer, chemical reactions, and electrical properties) a model was set up that is able to mirror the sensor behavior precisely, as the comparison with experimental data shows. A challenging task was to mesh the geometry due to scaling problems regarding the resolution of the thin catalyst layer in the much larger gas tube. Therefore, a coupling of a 3-D and a 1-D geometry is shown. This enables to calculate the overall temperature distribution, fluid flow, and gas concentration distribution in the 3-D model, while a very accurate calculation of the chemical reactions is possible in a 1-D dimension. This work does not only give insight into the results at stationary conditions for varying feed gas concentrations and used substrate materials but shows also how various exhaust gas species behave under transient temperature modulation.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Institutionen der Universität: Fakultäten > Fakultät für Ingenieurwissenschaften
Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Funktionsmaterialien > Lehrstuhl Funktionsmaterialien - Univ.-Prof. Dr.-Ing. Ralf Moos
Profilfelder > Advanced Fields > Neue Materialien
Forschungseinrichtungen > Forschungszentren > Bayreuther Materialzentrum - BayMAT
Forschungseinrichtungen > Forschungsstellen > ZET - Zentrum für Energietechnik
Forschungseinrichtungen > Forschungsstellen > BERC - Bayreuth Engine Research Center
Fakultäten
Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Funktionsmaterialien
Profilfelder
Profilfelder > Advanced Fields
Forschungseinrichtungen
Forschungseinrichtungen > Forschungszentren
Forschungseinrichtungen > Forschungsstellen
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften
Eingestellt am: 10 Jan 2018 08:06
Letzte Änderung: 10 Jan 2018 08:06
URI: https://eref.uni-bayreuth.de/id/eprint/41592