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The analysis of chemical time scales in a partial oxidation flame

Prüfert, U. and Hunger, F. and Hasse, C. (2014):
The analysis of chemical time scales in a partial oxidation flame.
In: Combustion and Flame, pp. 416-426, 161, ISSN 0010-2180,
DOI: 10.1016/j.combustflame.2013.09.001,
[Online-Edition: http://dx.doi.org/10.1016/j.combustflame.2013.09.001],
[Article]

Abstract

Abstract Time scale analysis is a well-established method in combustion science to identify slow and fast processes, but is also required for multi-scale modeling of turbulence-chemistry interaction. Models such as flamelet are based on scale separation arguments, which require a suitable definition of chemical time scales. In this article we study different time scale definitions. Two definitions previously published in the literature as well as two new definitions are investigated in detail. Most time scales require the computation of the eigenvalues of the chemical Jacobian, which is computationally expensive especially for larger chemical reaction mechanisms. One of the new definitions also requires the Jacobian of the chemical source term, whereas the computation of the second newly proposed time scale is computationally straight-forward since neither one is needed. We evaluate the four methods on a simple one-step reacting system and a partial oxidation flame which combines an oxy-fuel type reaction and a fuel-rich reforming post flame zone. Most of the considered time scale definitions provide similar results whereas the computational effort differs significantly.

Item Type: Article
Erschienen: 2014
Creators: Prüfert, U. and Hunger, F. and Hasse, C.
Title: The analysis of chemical time scales in a partial oxidation flame
Language: English
Abstract:

Abstract Time scale analysis is a well-established method in combustion science to identify slow and fast processes, but is also required for multi-scale modeling of turbulence-chemistry interaction. Models such as flamelet are based on scale separation arguments, which require a suitable definition of chemical time scales. In this article we study different time scale definitions. Two definitions previously published in the literature as well as two new definitions are investigated in detail. Most time scales require the computation of the eigenvalues of the chemical Jacobian, which is computationally expensive especially for larger chemical reaction mechanisms. One of the new definitions also requires the Jacobian of the chemical source term, whereas the computation of the second newly proposed time scale is computationally straight-forward since neither one is needed. We evaluate the four methods on a simple one-step reacting system and a partial oxidation flame which combines an oxy-fuel type reaction and a fuel-rich reforming post flame zone. Most of the considered time scale definitions provide similar results whereas the computational effort differs significantly.

Journal or Publication Title: Combustion and Flame
Volume: 161
Divisions: 16 Department of Mechanical Engineering > Simulation of reactive Thermo-Fluid Systems (STFS)
16 Department of Mechanical Engineering
Date Deposited: 29 Nov 2017 14:59
DOI: 10.1016/j.combustflame.2013.09.001
Official URL: http://dx.doi.org/10.1016/j.combustflame.2013.09.001
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