Rong FENG, Zhipeng MENG, Jiajian ZHU, Bo WANG, Mingbo SUN, Xiaoqing CHEN, Chao DING
DOI Number: XXX-YYY-ZZZ
Conference number: HiSST2024-00232
A multi-channel gliding arc (MCGA) plasma is utilized to extend the lean blow-off limit of the cavity shear-layer flame in the scramjet combustor. Optical measurements including high-speed flame chemiluminescence, high-speed CHemissions, and high-speed schlieren are employed to characterize the combustion process assisted by the plasma. The results show that the lean blow-off limit of the cavity shear-layer flame is extended by 21% when the MCGA plasma is added. The flame is blown out eventually due to the strong turbulence and the unstable fuel/air mixing near the lean blow-off limit. When the plasma is added, the plasma can sustain the flame in the entire combustion process. The small flakes of the flame which is nearly extinguished tend to attach to the plasma region, indicating that the MCGA plasma can strengthen the flame stability near the lean blow-off limit, leading to the cavity shear-layer flame held by the plasma. A plausible mechanism for the flame stabilized by the MCGA plasma is revealed that the temperature near the plasma is enhanced by the heat and active radicals (N, H atom) produced by the MCGA plasma, which sustain the flame near the plasma region. Meanwhile, the small flakes of the flame spread to the half back of the cavity to form the global flame with suitable turbulence conditions and approximate local equivalence ratios.