Experimental investigations on the pulsating jet-impinging diffusion flame were executed. A solenoid valve was aligned upstream of tile jet orifice and the methane fuel was controlled in open-closed cycles from 0 Hz t...Experimental investigations on the pulsating jet-impinging diffusion flame were executed. A solenoid valve was aligned upstream of tile jet orifice and the methane fuel was controlled in open-closed cycles from 0 Hz to 20 Hz. Results show that the open-closed cycles indeed increase the fluctuations of the methane fuel obviously. The evolutions of pulsating flame therefore develop faster than the continuous impinging flame. The optimized pulsating frequencies are near 9 to 11 Hz from the Re = 170 to 283. The temperature differences between that under optimized pulsating rate and full open condition (no pulsation) are ranging from 100 to 150 degree. The pulsating effect is more significant at low Reynolds number. The cross section of continuous impinging flame behaves as elliptic shape with axial ratio equals to 2/3. The tip of the impinging flame obviously crosses at 42 mm above the impinging point. Because of the phenomenon of pulsation flame, the flame sheet or flame front may not be identified clearly in the averaged temperature contours. Results show that the averaged end-contour of pulsation flame rears at 38 mm above the impinging point. By observation and experiment, the pulsating flame behaves more stable and efficient than the continuous impinging flame.展开更多
文摘Experimental investigations on the pulsating jet-impinging diffusion flame were executed. A solenoid valve was aligned upstream of tile jet orifice and the methane fuel was controlled in open-closed cycles from 0 Hz to 20 Hz. Results show that the open-closed cycles indeed increase the fluctuations of the methane fuel obviously. The evolutions of pulsating flame therefore develop faster than the continuous impinging flame. The optimized pulsating frequencies are near 9 to 11 Hz from the Re = 170 to 283. The temperature differences between that under optimized pulsating rate and full open condition (no pulsation) are ranging from 100 to 150 degree. The pulsating effect is more significant at low Reynolds number. The cross section of continuous impinging flame behaves as elliptic shape with axial ratio equals to 2/3. The tip of the impinging flame obviously crosses at 42 mm above the impinging point. Because of the phenomenon of pulsation flame, the flame sheet or flame front may not be identified clearly in the averaged temperature contours. Results show that the averaged end-contour of pulsation flame rears at 38 mm above the impinging point. By observation and experiment, the pulsating flame behaves more stable and efficient than the continuous impinging flame.
