The ion current response of a laminar lifted non-premixed flame in a DC electric field

Abstract

This study investigates the impact of a DC electric field on the lift-off height and ion current of a laminar lifted non-premixed jet flame. The experimental setup includes two horizontal electrodes that creates a vertical electric field aligned with the jet flow, with a positive field directing from the burner toward the downstream electrode. Results show that a DC electric field, regardless of polarity, reduces the flame lift-off height, with sufficiently strong fields causing flame reattachment. Flames with higher fuel flow rates exhibit larger lift-off heights and require stronger electric fields for reattachment, whereas lower flow rates are more sensitive to the applied field. Negative electric fields are more effective at reducing lift-off height and generating higher ion currents than positive fields. Ion current measurements reveal a strong correlation between field strength and flame reattachment, with ion current increasing significantly as the flame transitions from lift-off to reattachment. The study proposes a scaling relation between ion current, flame lift-off height, and electric field strength, demonstrating that ionic wind driven by the electric force plays a crucial role in flame stabilization. These findings suggest that DC electric fields offer a promising approach for controlling flame behavior, with potential applications in enhancing combustion efficiency and stability.