Extinction of pool flames by means of a DC electric field

The application of an electric field to a combustion system can produce large and potentially useful effects, such as reducing carbon formation, affecting flame velocity, extending flammability limits, increasing flame luminosity, and stabilizing and extinguishing flame. The present study is concerned primarily with the corona discharge interaction with pool fires. The fuel surface served as the blunt electrode and several specially designed sharp probes have been examined as the high-voltage electrode. The most effective sharp electrode appeared to be a simple thin wire parallel to the liquid surface situated above it at a distance of several millimeters. The flame was repelled from the probe, thus creating a possible pool flame extinction device. Similar results were achieved with a mechanical blower that reproduced the velocity profile of the electric wind. The gas composition in different locations was examined for both the corona and blower cases. No significant difference was found, and it was concluded that ion pumping has no influence on the extinction performance. It is suggested that extinction by corona discharge is caused solely by the aerodynamic action of the electric wind with its remarkably flat, sharp velocity profile. Fire extinctions under hot and aggressive environments are possible applications of the present device.