Feasibility of the Constrained Free Energy Method for Modeling NO Formation in Combustion

Petteri Kangas, Pertti Koukkari, Anders Brink, Mikko Hupa

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)

Abstract

Emissions of nitrogen oxide (NO) from combustion are modeled based on the constrained free energy method (CFE). The CFE method is an extension of the Gibbs' free energy minimization technique, using additional immaterial constraints which allow for the calculation of local thermodynamic equilibria. Chemical reactions, enthalpic effect, and thermochemical state variables are calculated concurrently. Various kinetic constraints were applied in this study for modeling thermal and fuel-based NO emissions for a number of combustion problems. The results were validated against data obtained from detailed kinetic models. The results indicate that the CFE method can be used for modeling post-flame thermal and fuel-based NO emissions. Where more specific estimation of radical buildup, radical overshoot, and ignition delay is needed, however, the accuracy of the applied CFE method was deemed insufficient.
Original languageEnglish
Pages (from-to)1173-1182
JournalChemical Engineering and Technology
Volume38
Issue number7
DOIs
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed

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Nitrogen oxides
Free energy
Nitric Oxide
Kinetics
Gibbs free energy
Ignition
Chemical reactions
Thermodynamics
Hot Temperature

Keywords

  • Gibbs' free energy
  • global reaction rate
  • local thermodynamic equilibrium
  • NO emission
  • reduced kinetic model

Cite this

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title = "Feasibility of the Constrained Free Energy Method for Modeling NO Formation in Combustion",
abstract = "Emissions of nitrogen oxide (NO) from combustion are modeled based on the constrained free energy method (CFE). The CFE method is an extension of the Gibbs' free energy minimization technique, using additional immaterial constraints which allow for the calculation of local thermodynamic equilibria. Chemical reactions, enthalpic effect, and thermochemical state variables are calculated concurrently. Various kinetic constraints were applied in this study for modeling thermal and fuel-based NO emissions for a number of combustion problems. The results were validated against data obtained from detailed kinetic models. The results indicate that the CFE method can be used for modeling post-flame thermal and fuel-based NO emissions. Where more specific estimation of radical buildup, radical overshoot, and ignition delay is needed, however, the accuracy of the applied CFE method was deemed insufficient.",
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Feasibility of the Constrained Free Energy Method for Modeling NO Formation in Combustion. / Kangas, Petteri; Koukkari, Pertti; Brink, Anders; Hupa, Mikko.

In: Chemical Engineering and Technology, Vol. 38, No. 7, 2015, p. 1173-1182.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Feasibility of the Constrained Free Energy Method for Modeling NO Formation in Combustion

AU - Kangas, Petteri

AU - Koukkari, Pertti

AU - Brink, Anders

AU - Hupa, Mikko

PY - 2015

Y1 - 2015

N2 - Emissions of nitrogen oxide (NO) from combustion are modeled based on the constrained free energy method (CFE). The CFE method is an extension of the Gibbs' free energy minimization technique, using additional immaterial constraints which allow for the calculation of local thermodynamic equilibria. Chemical reactions, enthalpic effect, and thermochemical state variables are calculated concurrently. Various kinetic constraints were applied in this study for modeling thermal and fuel-based NO emissions for a number of combustion problems. The results were validated against data obtained from detailed kinetic models. The results indicate that the CFE method can be used for modeling post-flame thermal and fuel-based NO emissions. Where more specific estimation of radical buildup, radical overshoot, and ignition delay is needed, however, the accuracy of the applied CFE method was deemed insufficient.

AB - Emissions of nitrogen oxide (NO) from combustion are modeled based on the constrained free energy method (CFE). The CFE method is an extension of the Gibbs' free energy minimization technique, using additional immaterial constraints which allow for the calculation of local thermodynamic equilibria. Chemical reactions, enthalpic effect, and thermochemical state variables are calculated concurrently. Various kinetic constraints were applied in this study for modeling thermal and fuel-based NO emissions for a number of combustion problems. The results were validated against data obtained from detailed kinetic models. The results indicate that the CFE method can be used for modeling post-flame thermal and fuel-based NO emissions. Where more specific estimation of radical buildup, radical overshoot, and ignition delay is needed, however, the accuracy of the applied CFE method was deemed insufficient.

KW - Gibbs' free energy

KW - global reaction rate

KW - local thermodynamic equilibrium

KW - NO emission

KW - reduced kinetic model

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JO - Chemical Engineering and Technology

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SN - 0930-7516

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