BEHAVIOUR OF LAMINAR PREMIXED FLAME EXPOSED TO ALTERNATING ELECTRIC FIELD

Abstract

Combustion in the lean regime is an efficient way to improve combustion efficiency, minimize the emission of pollutants and fuel consumption. The drawback is that instabilities appear which may lead to extinction of the flame or blow-out. Among the different methods for improving the flame characteristics at lean mixtures is the application of electric field. The purpose of the present work is to elucidate experimentally the effect of electric field on laminar partial premixed flame characteristics. Temperature distribution inside flame, flame geometry (height and width), and reaction zone thickness were measured at different mixture strengths with and without the application of electric field and its orientation. The results showed that under the effect of electric field, the flame height decreases with enriching the mixture in the lean side, while the width increases with a higher rate. The minimum difference between change of the flame height and flame width occurs at slightly rich mixture of equivalence ratio equals to 1.03. The reaction zone thickness increases as the electric field is applied on the flame. The change in temperature inside the flame when the electric field is applied is marginal. Electric field makes flame stabilized until reaching a lean flammability limit (ϕ = 0.67). Horizontal electrodes give a little effect on the flame characteristics represented by temperature.