Experimental Investigation on Gliding Arc Plasma Ignition and Assisted Combustion Actuator

In a scramjet engine, the viscosity of kerosene increases, the oxygen content decreases, the atomization evaporation rate and chemical reaction rate of kerosene decrease significantly, and the flame propagation speed decreases significantly under the condition of low total temperature, leading to the difficulty of ignition. Therefore, it is urgent to innovate the repeatable ignition method suitable for ramjet from the source. Gliding arc plasma has the advantages of both thermal equilibrium and nonequilibrium plasma. It can be used as a stable high-temperature heat source and chemical reaction source to strengthen the whole process from ignition to flame combustion, which has a critical application prospect in broadening the ignition boundary of scramjet engines at low total temperature and improving flame stability. In this article, a gliding arc plasma igniter is designed and developed. The research of gliding arc plasma ignition technology in scramjet combustor is carried out from two aspects of the discharge characteristics of gliding arc plasma igniter and kerosene cracking characteristics experiment. The results show that the average power of the gliding arc igniter in the air environment is higher than that in the nitrogen environment. With the increase of flow rate, the average power of the igniter increases first and then decreases. The maximum average power of the igniter with nitrogen is 193.56 W, and the maximum average power in the air environment is 323.49 W. The cracking products of kerosene are mainly hydrogen, methane, ethylene, acetylene, and other hydrocarbons below C3. The concentration of the product was positively correlated with the excitation voltage and channel length, and the concentration of hydrogen was the largest. The concentration of cracking products is higher in air, where hydrogen is three times higher than that in nitrogen. The main flow ignition of scramjet was successfully achieved under the condition of 2-Ma inlet velocity and 1000 K inlet temperature.