Impact of different air flow velocities on the performance of <?A3B2 pi6?>porous media micro-premixed burner

<bold> </bold>An experimental study was conducted on a clustered bluff-body burner employing a porous media micro-premixed structure under varying air flow velocities. The effects of different air flow velocities on the flame structure, combustion instability, and NO_{<italic>x</italic>} emissions of the porous media micro-premixed burner were investigated. High-frequency flame structure images were captured using the OH radical chemiluminescence method, pressure pulsation signals in the combustion chamber were measured with microphone sensors, and NO_{<italic>x</italic>} content in the combustion exhaust gas was analyzed using a gas component analyzer. The results indicate that as the air flow velocity increases, the reaction zone in the average flame image of the porous media micro-premixed clustered burner shifts slightly downstream, leading to an elongation of the flame length. At air flow velocities of 30 m/s and 42 m/s, the porous media micro-premixed burner exhibits significant thermoacoustic coupling oscillation combustion issues, resulting in higher NO_{<italic>x</italic>} emissions. However, at higher air flow velocities, the burner is able to achieve stable combustion with notably reduced NO_{<italic>x</italic>} emissions. By utilizing methods such as statistical distribution probability of the reaction zone along the axial direction and POD/DMD decomposition, it has been discovered that the thermoacoustic oscillations in the clustered burner exhibits axial oscillation characteristics. Additionally, the characteristic structures of pulsating flames under oscillating conditions are extracted, providing guidance for subsequent optimization of burner structural parameters and flow field control.