Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon
Uncertainty quantification (UQ) methods are implemented to obtain a quantitative characterization of the evolution of electrons and ions during the ignition of methane–oxygen mixtures under lean and stoichiometric conditions. The GRI-Mech 3.0 mechanism is combined with an extensive set of ion chemis...
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sg-ntu-dr.10356-1063672019-12-06T22:09:59Z Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon Kim, Daesang Rizzi, Francesco Cheng, Kwok Wah Han, Jie Bisetti, Fabrizio Knio, Omar Mohamad School of Civil and Environmental Engineering DRNTU::Engineering::Environmental engineering Uncertainty quantification (UQ) methods are implemented to obtain a quantitative characterization of the evolution of electrons and ions during the ignition of methane–oxygen mixtures under lean and stoichiometric conditions. The GRI-Mech 3.0 mechanism is combined with an extensive set of ion chemistry pathways and the forward propagation of uncertainty from model parameters to observables is performed using response surfaces. The UQ analysis considers 22 uncertain rate parameters, which include both chemi-ionization, proton transfer, and electron attachment reactions as well as neutral reactions pertaining to the chemistry of the CH radical. The uncertainty ranges for each rate parameter are discussed. Our results indicate that the uncertainty in the time evolution of the electron number density is due mostly to the chemi-ionization reaction CH + O ⇌ HCO+ + E− and to the main CH consumption reaction CH + O2 ⇌ O + HCO. Similar conclusions hold for the hydronium ion H3O+, since electrons and H3O+ account for more than 99% of the total negative and positive charge density, respectively. Surprisingly, the statistics of the number density of charged species show very little sensitivity to the uncertainty in the rate of the recombination reaction H3O+ + E− → products, until very late in the decay process, when the electron number density has fallen below 20% of its peak value. Finally, uncertainties in the secondary reactions within networks leading to the formation of minor ions (e.g., C2H3O+, HCO+, OH−, and O−) do not play any role in controlling the mean and variance of electrons and H3O+, but do affect the statistics of the minor ions significantly. The observed trends point to the role of key neutral reactions in controlling the mean and variance of the charged species number density in an indirect fashion. Furthermore, total sensitivity indices provide quantitative metrics to focus future efforts aiming at improving the rates of key reactions responsible for the formation of charges during hydrocarbon combustion. Accepted version 2015-07-14T01:09:27Z 2019-12-06T22:09:59Z 2015-07-14T01:09:27Z 2019-12-06T22:09:59Z 2015 2015 Journal Article Kim, D., Rizzi, F., Cheng, K. W., Han, J., Bisetti, F., & Knio, O. M. (2015). Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon. Combustion and flame, 162(7), 2904-2915. 0010-2180 https://hdl.handle.net/10356/106367 http://hdl.handle.net/10220/34962 http://dx.doi.org/10.1016/j.combustflame.2015.03.013 en Combustion and flame © 2015 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Combustion and Flame, Elsevier. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1016/j.combustflame.2015.03.013]. 49 p. application/pdf |
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DRNTU::Engineering::Environmental engineering Kim, Daesang Rizzi, Francesco Cheng, Kwok Wah Han, Jie Bisetti, Fabrizio Knio, Omar Mohamad Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon |
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Uncertainty quantification (UQ) methods are implemented to obtain a quantitative characterization of the evolution of electrons and ions during the ignition of methane–oxygen mixtures under lean and stoichiometric conditions. The GRI-Mech 3.0 mechanism is combined with an extensive set of ion chemistry pathways and the forward propagation of uncertainty from model parameters to observables is performed using response surfaces. The UQ analysis considers 22 uncertain rate parameters, which include both chemi-ionization, proton transfer, and electron attachment reactions as well as neutral reactions pertaining to the chemistry of the CH radical. The uncertainty ranges for each rate parameter are discussed. Our results indicate that the uncertainty in the time evolution of the electron number density is due mostly to the chemi-ionization reaction CH + O ⇌ HCO+ + E− and to the main CH consumption reaction CH + O2 ⇌ O + HCO. Similar conclusions hold for the hydronium ion H3O+, since electrons and H3O+ account for more than 99% of the total negative and positive charge density, respectively. Surprisingly, the statistics of the number density of charged species show very little sensitivity to the uncertainty in the rate of the recombination reaction H3O+ + E− → products, until very late in the decay process, when the electron number density has fallen below 20% of its peak value. Finally, uncertainties in the secondary reactions within networks leading to the formation of minor ions (e.g., C2H3O+, HCO+, OH−, and O−) do not play any role in controlling the mean and variance of electrons and H3O+, but do affect the statistics of the minor ions significantly. The observed trends point to the role of key neutral reactions in controlling the mean and variance of the charged species number density in an indirect fashion. Furthermore, total sensitivity indices provide quantitative metrics to focus future efforts aiming at improving the rates of key reactions responsible for the formation of charges during hydrocarbon combustion. |
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School of Civil and Environmental Engineering |
author_facet |
School of Civil and Environmental Engineering Kim, Daesang Rizzi, Francesco Cheng, Kwok Wah Han, Jie Bisetti, Fabrizio Knio, Omar Mohamad |
format |
Article |
author |
Kim, Daesang Rizzi, Francesco Cheng, Kwok Wah Han, Jie Bisetti, Fabrizio Knio, Omar Mohamad |
author_sort |
Kim, Daesang |
title |
Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon |
title_short |
Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon |
title_full |
Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon |
title_fullStr |
Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon |
title_full_unstemmed |
Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon |
title_sort |
uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon |
publishDate |
2015 |
url |
https://hdl.handle.net/10356/106367 http://hdl.handle.net/10220/34962 http://dx.doi.org/10.1016/j.combustflame.2015.03.013 |
_version_ |
1681043890884313088 |