Explicit reduced reaction models for ignition, flame propagation, and extinction of C{sub 2}H{sub 4}/CH{sub 4}/H{sub 2} and air systems

Journal Article · Sun Jul 15 00:00:00 EDT 2007 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2007.03.003· OSTI ID:20919412

Zambon, A C; Chelliah, H K ^[1]

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1. Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904-4746 (United States)

Large-scale simulations of multidimensional unsteady reacting flows with detailed chemistry and transport can be computationally extremely intensive even on distributed computing architectures. With the development of computationally efficient reduced chemical kinetic models, the smaller number of scalar variables to be integrated can lead to a significant reduction in the computational time required for the simulation with limited loss of accuracy in the results. A general MATLAB-based automated procedure for the development of reduced reaction models is presented. Based on the application of the quasi-steady-state (QSS) approximation for certain chemical species and on the elimination of selected fast elementary reactions, any complex starting reaction mechanism (detailed or skeletal) can be reduced with minimal human intervention. A key feature of the reduction procedure is the decoupling of the QSS species appearing in the QSS algebraic relations, enabling the explicit solution of the QSS species concentrations, which are needed for the evaluation of the elementary reaction rates. In contrast, previous approaches mainly relied on an implicit solution, requiring computationally intensive inner iterations. The automated procedure is first tested with the generation of an implicit 5-step reduced reaction model for CH{sub 4}/air flame propagation. Next, two explicit robust reduced reaction models based on ignition data (18-step) and on flame propagation data (15-step) are systematically developed and extensively validated for ignition delay time, flame propagation, and extinction predictions of C{sub 2}H{sub 4}/air, CH{sub 4}/air, and H{sub 2}/air systems over a wide range of equivalence ratios, initial temperatures, pressures, and strain rates. In order to assess the computational advantages of the explicit reduced reaction models, comparisons of the computational time required to evaluate the chemical source terms as well as for the integration of unsteady nonpremixed flames for each model are also presented. (author)

• OSTI ID: 20919412
• Journal Information: Combustion and Flame, Vol. 150, Issue 1-2; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
METHANE
ETHYLENE
AIR
HYDROGEN
CHEMICAL REACTION KINETICS
FLAME PROPAGATION
COMPARATIVE EVALUATIONS
IGNITION
APPROXIMATIONS
MATHEMATICAL SOLUTIONS
STEADY-STATE CONDITIONS
COMPUTERIZED SIMULATION
FLAME EXTINCTION
STRAIN RATE
TIME DELAY
ACCURACY
DECOUPLING
FLAMES
SCALARS