Investigation on the Flame Dynamics and Thermoacoustic Instability in a Novel Hydrogen Fuel Micro-Mix Burner with Time Delay Analysis

Experiments are conducted to investigate the effect of hydrogen content on the thermoacoustic instability in a novel hydrogen fuel micro-mix burner. The increase in hydrogen content tends to lead to the occurrence of high-frequency (approximately 800∼840 Hz) thermoacoustic oscillations. The oscillations of flames are axial modes, specifically manifested in the middle and tail of the flames. The analysis of total time delay to acoustic period ttotal/t reveals a critical limit k to distinguish the regimes of thermoacoustic oscillation and stable combustion. The importance of chemical reaction time delay is emphasized. As the hydrogen content increases, ttotal/t becomes smaller and less sensitive to adiabatic flame temperature.