City Research Online

Abstract

Wake flows are the preferred mode of flame stabilization in lean premixed combustion in gas turbine engines, low NOx burners, afterburners etc. These flows exhibit inherent unsteadiness and for their numerical modeling and simulations, large eddy simulation (LES) techniques with an appropriate combustion model and reaction mechanism afford a balance between computational complexity and predictive accuracy. Before using them in practical systems, these techniques must be validated against experimental measurements in a number of canonical cases. In this work, results from LES of non-reacting and reacting flows are compared to data from a number of experiments, corresponding to the following configurations: a triangular bluff body in a rectangular duct, a backward facing step, and a cylindrical sudden expansion with swirl. The artificial flame thickening approach is applied for modeling turbulence-combustion interactions at small scales. Algebraic and equationbased efficiency function models are implemented, along with an appropriate reduced chemistry mechanism. A novel dynamic formulation for the efficiency function based on the flame-wrinkling equation that explicitly incorporates the influence of strain and time-history effects is proposed, and a detailed combustion chemistry mechanism is also used. Results show that the approaches are effective in simulating turbulent premixed combustion.

Publication Type:	Article
Additional Information:	© 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
Subjects:	T Technology > TJ Mechanical engineering and machinery
Departments:	School of Science & Technology > Engineering

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