ARC Research
Kinetic Ignition Enhancement of Diffusion Flames by Nonequilibrium Magnetic Gliding Arc Plasma
Timothy Ombrello, Yiguang Ju and Alexander Fridman
Published 2 May 2012
Kinetic ignition enhancement of CH 4 –air and H 2 –air diffusion flames by a nonequilibrium plasma discharge of air was studied experimentally and numerically through the development of a well-defined counterflow system. Measurements of ignition temperatures and major species, as well as computations of rates of production and sensitivity analyses, were performed to understand the kinetic enhancement pathways for ignition by plasma discharge of air. It was found that plasma discharge of air led to significant kinetic ignition enhancement illustrated by large decreases in the ignition temperatures for a broad range of strain rates. Examination of the radical and NO x production in the plasma showed that the enhancement was caused primarily by the catalytic effect of NO x . The results of numerical simulations of the counterflow burner with preheated air and NO x addition showed the existence of different ignition regimes, which appeared due to the competition between radical production by NO x and other pathways, as well as heat release. There were two ignition regimes for small concentrations of NO x and three ignition regimes for large concentrations of NO x . Numerical simulations agreed well with the experimental measurements and suggested a new strategy for plasma-assisted ignition in supersonic flow, where a combination of thermal and nonthermal plasma would work more efficiently for ignition enhancement.
