Gliding arc plasma excitation on the atomization performance of pre-combustion injector in multi-swirl combustor

Realizable atomization and mixing of high temperature-rise combustors under wide operating conditions are critical for ensuring the stability of aviation turbine engines. Non-equilibrium plasma has garnered significant attention as a potential active control method to enhance engine atomization and ignition. This study introduces a novel “non-equilibrium gliding arc plasma-excited atomization” method. Experimental investigations were conducted using a specially designed multi-swirl combustor for laser diagnostics of atomization characteristics in kerosene-N₂ flows. Atomization characteristics were analyzed under varying gas–fuel ratios and nitrogen flow rates with the presence and absence of plasma excitation. Experimental results reveal that the coupled mechanisms of gas-fluid ratios and flow rates dominated the atomization process within the pre-combustion injector. Atomization deterioration in the combustion chamber was caused by higher gas-fluid ratios and lower flow rates, resulting in poor spray dispersion, a narrowed spray cone angle, and large fuel droplet sizes. Gliding arc discharge in kerosene–nitrogen spray had a dynamic self-regulation process related to gas fluid ratios and flow rates. An increase in the nitrogen flow rates, along with a higher concentration of fuel droplets per unit volume and the aggregation of droplet clusters, exacerbated discharge instability and enhanced energy dissipation. Gliding arc plasma induced the coupled electric-thermo-aerodynamic effect, forming a plasma/kerosene interaction zone at the exit of the pre-combustion injector. This, in turn, further strengthened the fragmentation, atomization, and mixing of fuel droplets, thereby improving the spatial spray distribution and the droplet size distribution in combustion chambers. Our work substantiates the potential of gliding arc plasma-excited atomization for advanced aviation turbine engine applications.