Effect of electric fields on flame displacement speed of propagating premixed flames in tube

The effect of electric fields on flame displacement speed has been investigated experimentally by observing propagating premixed flames in a tube for methane/air mixtures. The flame displacement speeds were measured in both the normal and micro gravity conditions to substantiate the measurements. The results show that the flame displacement speeds were enhanced by both the AC and DC electric fields, as the flame approached to the high voltage electrode located on the one end of the tube. The enhancement of flame displacement speed was proportional to the square root of the electric field intensity, defined as the voltage applied divided by the distance of flame from the high voltage electrode, when the electric field intensity is sufficiently large. When the electric field intensity was low, there existed critical intensities, below which the electric fields did not influence the flame displacement speed. This critical electric field intensity correlated well with the flame displacement speed.