Experimental Investigation on Ignition of Hyperburner Based on Gliding Arc Plasma Igniter Driven by Pressure Difference

Abstract

The hyperburner is a key component of a TBCC engine, and its reliable ignition and stable operation are critical. The gliding arc plasma igniter driven by differential pressure has the technical advantages of low energy consumption and high jet temperature. In this paper, the electrical and flow characteristics of the gliding arc plasma igniter are studied, and the basic ignition experiment in the hyperburner is carried out. Electrical characteristic experiments show that the discharge duration, the evolution of the gliding arc and the fracture frequency are affected by the pressure difference between the inlet and outlet of the igniter (Δp). With the increase in Δp, the frequency of the trapezoidal envelope in the voltage and current waveforms increases, and the frequency of the evolution and fracture of the gliding arc increases. The continuous discharge time of the gliding arc decreases when Δp = 550 Torr. The flow characteristic experiments show that the velocity of the swirl sheath is increased and the protective effect on the gliding arc is enhanced with the increase in Δp. In the range of 20–550 Torr, the jet length first increases and then decreases with the increase in Δp. The jet length reaches a maximum of 31 mm at Δp = 50 Torr. Basic ignition experiments show that proper Δp can widen the lean ignition limit and shorten the ignition delay time. In the working conditions of this paper, the ignition effect is the best when Δp = 350 Torr, which can widen the lean ignition limit by 37.5% and shorten the ignition delay time by 17%. After increasing the oil–gas ratios, the combustion is more complete and the ignition delay time can be shortened by 93.1% at most.