关键词: 自适应湍流模型（SATES）, 建表燃烧模型（FGM）, 热声耦合振荡燃烧, 部分预混燃烧, 火焰面密度（FSD）模型

Abstract:

The lean-fuel combustion method is widely used in the combustion chamber of aircraft engines and gas turbines. However， this method often encounters destructive unsteady thermoacoustic combustion instability problems. Numerical prediction of unsteady combustion instability is a long-term research hotspot and challenging problem. In this study， a coupled direct numerical simulation method for combustion instability is developed， coupling a high-fidelity Self-Adaptive Turbulence Eddy Simulation （SATES） method with optimized dynamic model parameters and a compressible tabulated FGM combustion model with detailed chemical reaction. Three turbulent combustion models are selected including the finite rate model （W1） and two Flame Surface Density （FSD） models of Zimont （W2） and Fureby （W3）. Numerical studies were carried out for the classical partially-premixed LIMOUSINE combustion chamber with combustion instability. It is found that the three combustion models under the SATES framework accurately predict the instability frequency of oscillating combustion， and the difference from the experimental data is small， which less than 6.4%. As to the prediction results of the instability amplitude of oscillating pressure， the finite rate model （W1） and Zimont （W2） model results are significantly larger than the experimental data， with the difference larger than 380%， and the Fureby （W3） model results are in good agreement with the experiments with the difference less than 17.9%. It is shown that the numerical prediction of combustion instability has high sensitivity to different turbulence and turbulent combustion models. The results from different test cases show that there are complete instability modes and transition modes in the combustion instability. The dominant frequency predicted by the numerical simulations in the complete instability mode tends to be consistent at multiple positions upstream and downstream of the combustion chamber. There are bimodal peaks in the predicted peak frequencies at different positions upstream and downstream in the transition instability mode， that is， dual-frequency mode. These results demonstrate that the numerical simulation method developed in the present study has high computational accuracy and reliability for the prediction of combustion instability.

Key words: Self-Adaptive Turbulence Eddy Simulation (SATES), Flame Generated Manifolds (FGM), thermoacoustic combustion instability, partially premixed flame, Flame Surface Density (FSD) models