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本文采用OH-PLIF探测系统对在McKenna平面火焰炉上产生CH_4/H_2/CO_2/O_2细胞状火焰进行了定量测量和分析。研究发现,平面火焰在稀燃极限附近会出现胞状结构,细胞数量随当量比/掺氢比的增加而增加,主要是由火焰自身不稳定性导致。同时我们通过OH-PLIF图片定量提取并定义了相关参数以表征平面火焰的不稳定程度,并发现随着火焰悬浮距离的减少火焰趋向于稳定,火焰对炉面的热损失有抑制不稳性发生的作用。通过线性理论分析,我们发现RS模型能够很好预测火焰稳定性随当量比变化趋势,但无法预测随掺氢比的变化趋势。在掺氢状态下,火焰面离炉面更近,炉面对火焰不稳定性的抑制作用不可忽视,故理论模型对掺氢影响的预测失效。
In this paper, OH-PLIF detection system was used to quantitatively measure and analyze the CH_4 / H_2 / CO_2 / O_2 cellular flame produced on the McKenna flat flame furnace. It was found that the planar structure of the flame flashed near the lean burn limit. The number of cells increased with the equivalence ratio / hydrogen addition ratio, which was mainly caused by the instability of flame itself. At the same time, we quantitatively extracted and defined OH-PLIF images to characterize the instability of planar flame and found that the flame tends to be stable with the reduction of the flame suspension distance, and the flame can not suppress the instability of the heat loss of the furnace surface Role. Through the linear theory analysis, we find that the RS model can well predict the flame stability with equivalence ratio trend, but can not predict the trend with the hydrogen incorporation ratio. In the hydrogen-doped state, the flame surface closer to the furnace surface, the furnace surface to suppress the instability of the flame can not be ignored, so the theoretical model of hydrogen doping prediction failure.