Large-eddy Simulations of Combustion Instabilities

Abstract

One of the most important issues in combustion researches is the prediction and suppression of combustion instability, which induces flashback, generates combustion noise and damages combustor. Although a number of studies on combustion instability have been performed, the underlying physics have not been well clarified yet, especially for spray combustion. In this article, authors' recent numerical works on Large-eddy Simulations (LES) of combustion instabilities are introduced. The combustion instabilities of gas and spray combustion in back-step flows are demonstrated in terms of LES, and effects of initial droplet diameter on the combustion instability are investigated for spray combustion. Methane and kerosene are used as fuels for gas and spray combustion, respectively, and two-step global reaction models are used for calculations of the reactions. A dynamic thickened flame model is employed as a turbulent combustion model.