Influence of non-thermal plasma and electric field on non-premixed methane flame

Abstract

Non-thermal plasma possesses several distinctive features such as low energy consumption, strong selectivity, and high activity. Consequently, it holds significant promise for applications in combustion control. Given the strong interdependence of its function with combustion physics and chemical processes, it is imperative to gain a comprehensive understanding of its underlying mechanism from various perspectives. Therefore, this paper aims to investigate the effects of the inherent electromagnetic properties of non-thermal plasma and electric field on methane combustion. Specifically, the focus is on the effects of electric field-driven ionic wind and electric field-enhanced chemical kinetics. Firstly, a design for a coaxial micro-tube burner was developed. By employing a method that involves the continuous modulation of the loading electric field and the utilization of PIV detection, this study aimed to observe the combustion characteristics of methane diffuse and lift-off flames. Additionally, the research sought to determine the variation patterns of the critical de-fire rate and combustion stability. The combustion velocity of a methane laminar flame was measured using the heat flux method, and the impact of an electric field on the flame velocity was determined. The main findings of this study reveal that the electric field and discharge current field play significant roles in ensuring combustion stability. Additionally, it is observed that ionic winds, acting as carriers for flame chemical reactions, and the chemical kinetic effects of non-thermal plasmas contribute positively to flame stability. Furthermore, both AC and DC electric fields generate an adsorption volume force on the surface of the flame.