Effects of electric fields on the combustion of methane gas

Abstract

Methane gas is a highly prized fuel in the world. However, the low burning velocity and instability of a flame creates some problems for the burning of natural gas. By applying an electric field, a means may be provided for effectively modifying the combustion process and subsequently stabilizing the flame. Although observations have been made over the years to explain the mechanism of the interaction of electric fields with flames in combustion, the interpretations have often been in doubt and inconsistencies abound in the literature. The main objective of this research was to develop a clear understanding of the interaction between electric fields and flames in combustion. Other objectives are: (i) determine, (a) the flame propagation velocity in a vertical tube, with and without applied longitudinal and transverse electric fields, and (b) the stability of methane gas flame; (ii) determine engineering applications and the directions for future research. Guided by theoretical consideration, experiments were conducted on the lower blowoff limits and flame propagation velocities of methane gas flames, with and without electric fields. By means of electrodes, transverse and longitudinal electric fields were applied to the flames. The results of the research indicate that electric fields, under suitable electrode configurations, can be used as a useful technique in controlling the combustion process. The power consumption from electric fields is very low (less than 1 watt, compared to about 10('3) watts of power obtained by burning 15 cc/sec of methane gas at standard conditions). However, since the major observed effects have been with flames of low flow rate, practical hardware-type applications have not been forthcoming. Further research is necessary before these results are extrapolated to large commercial applications.