Lean Blowout Limit Prediction for Combustion in a Swirler by a New IndicatorAssisted RANS Approach
Conference
Lin, CXC, Al-Rifai, S, Polanka, MD et al. (2022). Lean Blowout Limit Prediction for Combustion in a Swirler by a New IndicatorAssisted RANS Approach
. 10.2514/6.2022-0824
Lin, CXC, Al-Rifai, S, Polanka, MD et al. (2022). Lean Blowout Limit Prediction for Combustion in a Swirler by a New IndicatorAssisted RANS Approach
. 10.2514/6.2022-0824
Although popularly used in combustor design, Reynolds Averaged Navier-Stokes (RANS) equations based Computational Fluid Dynamics (CFD) approach faces difficulties in predicting the blowout limit. In this study, a simple indicator-assisted RANS CFD approach was evaluated to predict lean blowout (LBO) limit for a single swirler used in an ultra-compact combustor. The realizable k-ε turbulence model and steady diffusion flamelet combustion model were used to simulate the turbulent combustion of a propane-air mixture. Two forms of this LBO indicator, measuring either the relative change rate of average Damköhler number (Da) or temperature with respect to global equivalence ratio, were investigated with a new procedure to identify the lean blowout point. The two indicators were evaluated on four characteristic planes: two fixed cross-sectional planes, a 2/3rd flame height plane, and a temperature-range clipped flame section (TCFS). The indicator predicted LBO limits were also compared with experimental measurements with good agreement at different airflow rates. In general, the Da-based LBO indicator was more accurate than the temperature-based one within the examined parameter ranges. The indicator calculated on the TCFS plane was effective over a wider range of airflow rates than on other planes. The methodology was more suitable for moderate to high airflow rates than low airflow rates.
