Prediction of limit cycle oscillations in gas turbine combustion systems using the Flame Describing Function

摘要: Thermo-acoustic analysis is crucial for a successful development of new gas turbine combustion systems. In this context, it becomes more and more necessary to predict the limit cycle pressure amplitude thermo-acoustic combustion instabilities figure out if they are within critical design or will cause damage engine. For prediction amplitudes, nonlinear flame response system needed, which represented in work by Flame Describing Function (FDF). It investigated can be predicted using combination FDF, calculated from Computational Fluid Dynamics (CFD) simulations, low order thermoacoustic stability code. Two test cases investigated. The first case generic atmospheric swirl flame. saturation heat release response flame was observed during measurements, correctly captured by CFD, meaning that measured FDF showed good comparison. Next from CFD used together with thermo-acoustic stability code GIM amplitude. frequency instability 5%, 3.3 dB. A sensitivity study, however, small deviations between the measured simulated FDF’s lead significant differences the predicted This shows high fidelity CFD simulations must these kinds predictions. Most limit cycle predictions presented work correspond well experimental data, indicating quality FDF. The second corresponds an industrial system. The pressure 4.8 dB 6%, compared measurements. An important change identified: it was found burner could improved shifting the location fuel injection downstream, towards analysis therefore demonstrates strength proposed method cycle prediction.