Large Eddy Simulation to Predict Flame Front Position for Turbulent Lean Premixed Jet Flame at High Pressure

Abstract

To predict the flame front position, we adopt the large eddy simulation (LES) and incorporate into it a combustion model, the hybrid turbulent combustion model (HTC model), applicable to any flame mode. We take previously obtained test results for the axisymmetric jet lean premixed flame in a cylindrical chamber at high pressure and investigate the effects of equivalence ratio variation on flame front positions. Full details of these tests are available in the literature. We find the simulation results of the axial positions of the flame front points, defined by the inflection point of the OH concentration distributions, show good agreement with test results (less than 4% difference between them). Therefore, we conclude that the HTC model is capable of capturing the actually observed tendency when changing the equivalence ratios and that the combination of the HTC model with LES suggests that flame stretch effect is important to predict the flame front position for lean premixed combustion.

Prediction of CO emissions in turbulent super lean premixed combustion under pressurized conditions using an LES/non-adiabatic FGM approach

“…The decrease in the flame propagation rate is caused by the flame stretch effect. Previous studies [3] have suggested that introducing a flame stretch effect [27] into the combustion model improves the prediction accuracy of the flame length, particularly under lower equivalence ratio conditions. Further consideration is needed to yield any findings regarding the introduction of the flame stretch effect into the NA-FGM approach to improve the prediction accuracy of the flame length.…”

“…In particular, a large-eddy simulation (LES), which models an eddy smaller than the cell size, has gained increasing application in recent years, because the application of an LES to complex reacting flows has been realistic with advancements in the supercomputing performance [e.g. [2][3][4][5][6][7][8]. As the turbulent combustion model, the flamelet approach [9], which utilizes the flame characteristics in the database (i.e., the flamelet library), is effective in terms of computational costs and is widely used instead of directly solving the Arrhenius equations when considering the detailed chemical reaction mechanisms.…”

Numerical Simulation of CO Concentration on Flame Propagation in the Vicinity of the Wall -Validity of Non-Adiabatic FGM Approach-

“…Computational fluid dynamics (CFD) is a powerful tool to investigate the detailed distributions of various chemical species and temperature under the complicated combustion fields. CFD has been used to support to engineers in predicting the property of flame dynamics during the combustor design process [3][4][5][6][7][8][9]. Prediction of CO emission with high accuracies is required consideration of the detailed reaction mechanism in general.…”