Study of the volumetric effect of Transient Plasma Ignition in quiescent ethylene-air

Summary form only given: transient plasma ignition (TPI) uses short pulse lengths (typically < 100 ns) and high voltages (10´s of kV) to generate a non-equilibrium transient plasma discharge, allowing radicals and other electronically excited species to be produced over a relatively large volume compared to traditional spark ignition. Studies show that nanosecond pulsed power technology can lead to much shorter ignition delay times and pressure rise times than conventional spark ignition, and that ignition occurs along the anode. We report here studies of different length electrodes for TPI and traditional spark ignition in a combustion reactor with C₂H₄-air mixtures. The length of the anode and the output voltage of the pulse generator were varied, resulting in a change in the number of ignition kernels. As the length of the anode is decreased, the peak pressure approaches that achieved using a traditional spark plug, however the pressure rise and ignition delay remain shorter. The shape of the pressure curves for the TPI case with short electrodes indicates a more volumetric ignition in comparison to the spark plug, despite similar ignition geometry.