Time-resolved 3D investigation of the ignition process of a methane diffusion impinging flame

The ignition process of a methane diffusion impinging flame was investigated experimentally, using high speed schlieren/stereo imaging and image processing techniques. Two types of flame can be identified during the ignition process: premixed like flame with weak blue colour and diffusion flame with yellow-reddish colour. The 3D structure of blue flame after enhancement and yellow flame has been reconstructed and analysed seperately. The ratio between green and blue colour intensity is used to provide indications of the global fuel/air mixture state of the blue flame, which is found to correlate well with the flow conditions and flame propagation characteristics.