Experimental Investigation of the Ignition by Repetitive Streamer Discharges

A time-resolved study of the flame kernel growth after the ignition of different H 2/air mixtures at atmospheric pressure is reported. For this purpose, hydroxyl radicals are measured by means of planar laser-induced fluorescence (OH-PLIF). The H 2/air mixtures are ignited by repetitively pulsed streamer discharges which occur at atmospheric pressure within a rod/plane electrode configuration using alternating voltage amplitudes of up to 20 kV with a frequency of 740 kHz. The flame propagation is examined evaluating the flame front position from the signal intensities of the OH-PLIF. Numerical simulations of the ignition of H 2/air mixtures are performed using well-known detailed chemistry and transport models based on a one-dimensional model. Numerical and experimental flame kernel growths are compared showing excellent agreement. The results will be used to achieve a better understanding of the molecular reactions in the non-equilibrium plasma of repetitive streamer discharges.