Abstract
The lift-off phenomenon in turbulent jet flames has garnered significant attention, but it also presents the risk of fuel leakage and flame blowout. Stabilizing flames remains a significant challenge in aeroengines and gas turbines. Plasma-assisted combustion (PAC) is considered a promising and active technology for practical applications as it has the potential to improve flame stability and reduce pollutant emissions. This study investigates the combustion characteristics of lifted methane/air flames using high-voltage nanosecond and sinusoidal plasma generators. While nanosecond pulsed excitation of cold atmospheric plasmas is thought to offer advantages over sinusoidal excitation, direct comparisons between the two are rare, especially in the field of PAC. A needle-type plasma actuator was used in a swirl combustor near the nozzle exit, and the electrical characteristics and LBO limits of the two different types of plasma generators were compared. The flame structures with plasma discharge were characterized using high-speed chemiluminescence from electronically excited CH* and OH* radicals. Proper Orthogonal Decomposition (POD) of CH* and OH* chemiluminescence images was used to identify the dominant flame structures using different plasma generators.
