Structure of n-heptane/air triple flames in partially-premixed mixing layers

Results of a detailed numerical analysis of an n-heptane/air edge flame are presented. The equations of a low-Mach number reacting flow are solved in a two-dimensional domain using detailed models for species transport and chemical reactions. The reaction mechanism involves 560 species and 2538 reve...

Full description

Saved in:
Bibliographic Details
Published in:Combustion and flame 2011-11, Vol.158 (11), p.2128-2144
Main Authors: Prager, J., Najm, H.N., Valorani, M., Goussis, D.A.
Format: Article
Language:English
Subjects:
Accuracy
Applied sciences
Combustion
Combustion. Flame
Computation
Diffusion flames
Edge flames
Energy
Energy. Thermal use of fuels
Equivalence ratio
Exact sciences and technology
Mathematical models
n-heptane
Reduction
Theoretical studies. Data and constants. Metering
Triple flames
Two dimensional
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Results of a detailed numerical analysis of an n-heptane/air edge flame are presented. The equations of a low-Mach number reacting flow are solved in a two-dimensional domain using detailed models for species transport and chemical reactions. The reaction mechanism involves 560 species and 2538 reversible reactions. We consider an edge flame that is established in a mixing layer with a uniform velocity field. The mixing layer spans the equivalence ratios between pure air and 3.5. The detailed model enables us to analyze the chemical structure of the n-heptane edge flame. We identify major species profiles, discuss reactions causing the heat-release, and exploit Computational Singular Perturbation (CSP) to discuss the main fuel-consumption pathways and the structure of explosive modes in the edge flame. This analysis is performed for several regions in the edge flame to discuss the different processes at work in the premixed branches and the trailing diffusion flame. We compare different cuts through the 2D edge flame to canonical 1D premixed and diffusion flames. We also analyze the accuracy of a skeletal mechanism which was previously developed using CSP from homogeneous ignition calculations of n-heptane and show that a significant reduction in size of the mechanism can be achieved without a significant decrease in accuracy of the edge flame computation. This skeletal mechanism is then used to study the effects of increasing the equivalence ratio in the partially-premixed fuel stream.
ISSN:0010-2180
1556-2921
DOI:10.1016/j.combustflame.2011.03.017