Changhuai Hu

Against the background of demanding ignition stability requirements for high-temperature-rise aero-engine combustors, this paper numerically explores transient ignition and flame evolution in a gliding arc plasma-assisted multi-swirl combustor via a 3D two-phase URANS turbulent combustion approach. It employs the realizable k-ε, eddy dissipation concept, and discrete phase models alongside a self-built gliding arc trajectory and thermal-reaction coupling model to reproduce the full process of arc discharge, initial flame kernel generation, flame propagation, and self-sustained combustion. Results show that gliding arc plasma deposits energy and momentum to regulate local flow structure, fuel atomization, and active species generation including O and OH radicals. The initial flame kernel forms at 6.4 ms dominated by plasma-induced radical reactions and optimal local equivalence ratio. A newly defined heat release-dissipation Damköhler number (Da_hd) is proposed as a criterion for flame stability: Da_hd > 1 enables self-sustained flame propagation while Da_hd < 1 leads to flame extinction due to dominant turbulent dissipation. The intermediate recirculation zone and low-velocity zone provide favorable low-turbulence environments for flame anchoring. Eventually, the flame evolves into a stable V-shaped global propagation structure under the synergistic effect of plasma periodic energy supplementation, flow recirculation, and turbulent mixing. This paper reveals the multi-field coupling mechanism of plasma-flow-chemistry and provides a theoretical basis for the application of gliding arc plasma in aero-engine combustor ignition enhancement.

A gliding arc discharge is a typical method of producing non-equilibrium plasma, presenting excellent advantages in the field of enhanced combustion. In this study, a rotating gliding arc (RGA) plasma was combined with an aero-engine combustor dome to develop a RGA plasma-enhanced combustion dome. Experiments were conducted to investigate discharge, spectral, and infrared radiation temperature characteristics in the RGA plasma-enhanced combustion dome. Experimental results showed that two different discharge modes occurred during the RGA discharge process, the breakdown gliding mode and the steady arc gliding mode. The results had major implications for understanding the effects of the airflow rate and input voltage on the arc gliding mode transformation. The breakdown voltage, the average power, and the gliding arc rotational velocity increased with an increase in the airflow rate and a decrease of the input voltage. The spectral emission intensities of OH, O ₂ , and O and vibrational temperature of N ₂ (C ³ Π _u →B ³ Π _g ) were relatively high at a high airflow rate. Additionally, the RGA discharge had a weak temperature rise effect on electrode, which had no obvious impact on the discharge process. These characteristics could be important for future applications for controlling plasma-enhanced combustion process.