Laser Diagnostics of Combustion Enhancement on a CH ₄ /Air Bunsen Flame by Dielectric Barrier Discharge

Abstract

We investigate plasma-assisted combustion for premixed CH4/air Bunsen flames. Dielectric barrier discharge (DBD) is employed to produce non-equilibrium plasma for combustion enhancement. The transient planar laser induced fluorescence (PLIF) technique of CH and OH radicals is used to image reaction zones for enhancement measurement, and the emission spectra of the Bunsen flame are monitored to explore the kinetics mechanism. From the drift of radicals in PLIF images, the quantitative enhancement of plasma on the flame velocities of premixed methane/air flames is experimentally measured, and the data show that the flame velocities are increased by at least 15% in the presented equivalence ratio range. Furthermore, the well analyzed emission spectra of the Bunsen flame (300-800 nm) with/without DBD reveal that the emissions as well as the concentrations of the crucial radicals (like C2, CH, OH etc.) in combustion all are intensified greatly by the discharge. In addition, the appearance of excited spectral bands of N2 and N + 2 during discharge indicates that the premixed gas is also heated and ionized partially by the DBD.

Identification of flow structures in a closed chamber in the presence of a needle plasma actuator

“…They confirmed that with the use of AC-DBDPA, flame length and soot formation were decreased. Shao-Hua et al 32 concentrated the activation of methane/air flame by using cylindrical AC-DBDPA. The transient OH/CH-PLIF imaging was recorded to acquire the physical appearance and its changes in the Bunsen flame.…”