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Journal of Combustion
Volume 2011, Article ID 451351, 8 pages
http://dx.doi.org/10.1155/2011/451351
Research Article

Influence of Turbulent Scalar Mixing Physics on Premixed Flame Propagation

1Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94557-0969, USA
2Department of Engineering, Cambridge University, Cambridge CB2 1PZ, UK

Received 27 January 2011; Revised 26 May 2011; Accepted 20 June 2011

Academic Editor: Andrei N. Lipatnikov

Copyright © 2011 H. Kolla and N. Swaminathan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The influence of reactive scalar mixing physics on turbulent premixed flame propagation is studied, within the framework of turbulent flame speed modelling, by comparing predictive ability of two algebraic flame speed models: one that includes all relevant physics and the other ignoring dilatation effects on reactive scalar mixing. This study is an extension of a previous work analysing and validating the former model. The latter is obtained by neglecting modelling terms that include dilatation effects: a direct effect because of density change across the flame front and an indirect effect due to dilatation on turbulence-scalar interaction. An analysis of the limiting behaviour shows that neglecting the indirect effect alters the flame speed scaling considerably when 𝑢 / 𝑠 𝑜 𝐿 is small and the scaling remains unaffected when 𝑢 / 𝑠 𝑜 𝐿 is large. This is evident from comparisons of the two models with experimental data which show that the quantitative difference between the two models is as high as 66% at 𝑢 / 𝑠 𝑜 𝐿 = 0 . 3 but only 4% at 𝑢 / 𝑠 𝑜 𝐿 = 5 2 . 4 . Furthermore, neglecting the direct effect results in a poor prediction of turbulent flame speed for all values of 𝑢 / 𝑠 𝑜 𝐿 , and both effects are important for practically relevant values of this velocity ratio.