Effects of electric fields on the blowoff limits of a methane-air flame

Abstract

The flame was always ignited at low velocities (approximately 33 cmVs) with an alcohol burner. The field was then turned on and the methane and air flow rates increased simultaneously up to the total velocity at which the blowoff limits were to be determined. Blowoff points were obtained by maintaining a constant flow of either the methane or air, while varying the other flow until the flame left the burner port.By decreasing the gas flow rates, the lower blowoff limits were obtained, with and without electric fields. The upper blowoff points could not be obtained by increasing the gas flow rates because the flame picked up more air from the open surroundings at higher rates. As a result, another set of lower blowoff limits were obtained by keeping the gas flow rate constant and increasing the airflow rate. Figure 2 represents the configuration for the second geometry. A longitudinal electric field was obtained by placing an aluminum foil ring around the glass tube for one electrode and making the brass burner the other electrode. Following the procedures of the first geometry, lower blowoff limits were obtained, with and without electric fields.

The influence of pressure on the control of premixed turbulent flames using an electric field

“…They attributed the effect to an ionic wind induced by the interaction of the electric field with chemi-ions present in the flame. Noorani and Holmes [2] obtained an extension of 83% in the blowoff limit of a laminar premixed flame of methane and air. A systematic experimental study of the effects of electric fields on flame stability was presented by Calcote and Berman [3], who revealed effects on flame stability for laminar as well as turbulent flow.…”

Effects of Direct Current Electric Field on the Blowoff Characteristics of Bluff-Body Stabilized Conical Premixed Flames

“…In some of the early work on electric fieldflame interactions, Weinberg and coworkers (Lawton and Weinberg, 1969;Lawton et al, 1968;Browser and Weinberg, 1972) and Calcote and coworkers (Berman et al, 1991;Calcote, 1949;Calcote and Berman, 1989;Calcote and Pease, 1951) as well as others (Bradley and Nasser, 1984;Noorani and Holmes, 1985) have found a significant effect when an electric field is applied in the flame stabilization region. For example, the Bunsen burner flames studied by Calcote and Pease (1951) were stabilized at leaner fuel=air stoichiometries in the presence of an imposed electric field.…”

Observation of multi-scale oscillation of laminar lifted flames with low-frequency AC electric fields

“…The collision between the accelerated ions and neutral molecules transfers momentum such that bulk flow can be induced, generating the ionic wind effect. Flame speed modification, soot reduction, and improved flame stabilization have been observed [1][2][3][4][5][6][7][8][9]. Especially, the ionic wind effect has been extensively investigated by applying DC and pulsed DC electric fields, whereas, studies on the influence of AC electric fields are rather limited [10][11][12].…”