High Speed Digital Imaging for Flame Studies: Potentials and Limitations

Experience has shown that higher shutter speed or framing rate may cause signal drop out and the loss of the weak flame emission. On the other hand, slow shutter speed or frame rate will not be able to resolve the higher flame oscillation frequency. In this study, two synchronised high speed cameras are used to investigate the effect of camera shutter speed and frame rates on the colour imaging quality and oscillation frequency of a premixed methane flame. Through an innovative digital imaging enhancement technique, the weak blue flame colour pixels can be selectively enhanced for better visualisation and analysis. As a result, the same flame imaged at different shutter speed can be compared and contrasted with good accuracy. Test cases are carried out to provide better understanding of flame structure and dynamics.