Investigation of Modeling for Non-Premixed Turbulent Combustion

Authors: de Bruyn Kops S.M.¹; Riley J.J.¹; Kosály G.¹; Cook A.W.²

Source: Applied Scientific Research, Volume 60, Number 1, 1998 , pp. 105-122(18)

Publisher: Springer

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Abstract:

A method for predicting filtered chemical species concentrations and filtered reaction rates in Large-Eddy Simulations of non-premixed, non-isothermal, turbulent reacting flows has been demonstrated to be quite accurate for higher Damköhler numbers. This subgrid-scale model is based on flamelet theory and uses presumed forms for both the dissipation rate and subgrid-scale probability density function of a conserved scalar. Inputs to the model are the chemistry rates, the Favre-filtered scalar, and its subgrid-scale variance and filtered dissipation rate. In this paper, models for the filtered dissipation rate and subgrid-scale variance are evaluated by filtering data from 5123-point Direct Numerical Simulations of a single-step, isothermal reaction developing in the isotropic, incompressible, decaying turbulence field of Comte-Bellot and Corrsin. Both the subgrid-scale variance and the filtered dissipation rate models (the ``sub-models'') are found to be reasonably accurate. The effect of the errors introduced by the sub-models on the overall model is found to be small, and the overall model is shown to accurately predict the spatial average of the filtered species concentrations over a wide range of times.

Keywords: large-eddy simulations; reacting flows; subgrid-scale models

Language: English

Document Type: Regular paper

Affiliations: 1: Department of Mechanical Engineering, University of Washington, Box 352600, Seattle, WA 98195-2600, U.S.A. 2: L-2, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94550, U.S.A.

Publication date: 1998-01-01