Effect of nitrogen-containing plasmas on stability, NO formation and sooting of flames

Abstract

WE have been developing methods for burning leaner fuel/air mixtures at faster rates and with less pollution than is achieved in conventional systems^1–3. Mixtures of heat contents much below those corresponding to normal limits of flammability have been burned successfully at low temperatures using heat recirculation^4,5. At temperatures much above the melting point of heat exchangers large increases in burning rates for a small input of electricity were achieved when radicals from plasma jets were injected, using a magnetically rotated arc to achieve rapid mixing⁶. We now report on further effects which can be induced using even a much smaller plasma jet (of about the size of a conventional sparking plug), the addition of much smaller proportions of electrical energy (∼ 4% of the chemical through-put) and the absence of any magnetic field.