Soot control of laminar jet-diffusion lifted flame excited by high-frequency acoustic oscillation

A novel technology to reduce soot is developed utilizing a high-frequency standing wave of 20 kHz applied to a methane-air lifted jet flame base. The amount of soot was measured using the transmitted light attenuation method. A mixing profile of the fuel jet was visualized using acetone planar-laser-induced fluorescence in order to measure the mixing status when the ultrasonic wave was applied. The blow-off and reattached limit were increased by the standing wave. Soot was also clearly decreased under some conditions. This was detected both through a disappearance of the luminous flame and a qualitative measurement using the transmitted light attenuation method. The luminous intensity of the acetone fluorescence at the middle of the fuel jet decreased with height because the fuel jet diffused more efficiently with ultrasonic waves.