Investigation on the characteristics of dielectric barrier discharge in methane with parallel-plate and multi needle-plate electrode in low pressure

摘要

Summary form only given. Non-equilibrium plasma-assisted combustion has been extensively studied over the last few decades and has shown promising effects on combustion controlling, such as reducing ignition delay time, increasing flame propagation speed, enhancing flame stabilization and so on. In this paper, we investigated on the characteristics of dielectric barrier discharge (DBD) in methane with parallel-plate and multi-needle-to-plate electrodes under low pressure with sinusoidal waveform (20 kHz, 0-30 kV) power supply. A mechelle spectrometer (Mechelle 5000, Andor) is used to capture the plasma spectra. The results show that the discharge produces abundant active components related to combustion, such as CH (λ=392.5, 430.1, 438.7, 440.9nm), and C2 (A=473.6nm) in the excited level. Temperature of the active particles is calculated by LIFBASE software and platinum-rhodium thermocouple. With the increasing of applied voltage, the gas temperature and the number and average energy of the high-energy electrons are increased, leading to more free particles which are in the excited state, and finally the corresponding emission spectrum intensity is enhanced. Under the same gas pressure and electrode gap except for generation by different the electrode structure, the temperature of gas in multi needle-plate electrode is lower than plate-plate electrode. And it is proven that multi needles in a honeycomb structure layout can be made in more stable discharge, which can be used in sub-atmospheric even under atmospheric pressure, and it is better for plasma-assisted combustion application.