Research on the Characteristics of Oscillation Combustion Pulsation in Swirl Combustor

This study focuses on the center-staged swirl model combustion chamber, conducting experiments and numerical simulations to investigate the unstable combustion characteristics of diffusion flames under different Reynolds numbers and air–fuel ratios. The results were analyzed using methods such as Empirical Mode Decomposition (EMD), Fast Fourier Transform (FFT), and Proper Orthogonal Decomposition (POD). The research found that the first three intrinsic mode functions (IMFs) of the combustion chamber pressure fluctuation signal (DP) correspond to different physical fluctuation characteristics. Specifically, the 1st IMF represents the fluctuation characteristics of the heat release rate, corresponding to the flame shear region in the heat release rate field; the 2nd IMF represents the fluctuation characteristics of airflow swirl, corresponding to the swirl vortex structure region in the vorticity field; the 3rd IMF represents the flame detachment fluctuation characteristics, corresponding to the flame detachment region in the heat release rate field. Using the same experimental and numerical calculation methods to study another swirl model combustion chamber, the results also showed the aforementioned correspondence, further demonstrating the accuracy of the experimental results and the universality of this conclusion.