Ignition Parameters and Early Flame Kernel Development of Laser-Ignited Combustible Gas Mixtures

Laser induced breakdown of focused pulsed laser radiation, the subsequent plasma formation and thermalisation offers a possibility of combustible gas mixtures free from electrode interferences, an arbitrary choice of the location within the medium and exact timing regardless of the degree of turbulence. The development and the decreasing costs of solid state laser technologies approach the pay-off for higher complexity of such an ignition system due to several features unique to laser ignition. The early flame kernel development was investigated by time-resolved planar laser induced fluorescence of the OH-radical which occurs predominantly in the flame front. The flame front propagation shows typical features like toroidal initial flame development, flame front return and highly increased flame speed along the laser focus axis.