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在Rijke管产生的强迫脉动驻波声场下,以甲烷层流部分预混火焰为研究对象,比较了脉动燃烧与稳态燃烧下NO_x随当量比的变化规律,结合微细热电偶、火焰探针,讨论了火焰内部温度场和组分浓度变化,分析了脉动燃烧下NO_x降低机理。结果表明脉动燃烧下甲烷部分预混火焰的NO_x降低,其主要机理为:脉动燃烧下火焰的峰值温度低,温度分布均匀,局部高温区小;脉动使火焰内部的空气掺混量增加,强化了化学反应速率;脉动燃烧减小了反应区域,缩短了气体在高温区的停留时间,使得NO_x生成量小。
In the forced pulsation standing wave field generated by Rijke tube, the laminar premixed flame of methane laminar flow is taken as the research object. The variation law of equivalence ratio of NO_x under pulsating combustion and steady combustion is compared. Combined with the micro thermocouple, flame probe, The change of temperature field and component concentration in flame were discussed. The mechanism of NO_x reduction under pulsating combustion was analyzed. The results show that the NO_x of the premixed flame of methane is decreased under pulsatile combustion. The main mechanism is as follows: the peak temperature of pulsating combustion is low, the temperature is uniform and the local high temperature zone is small; pulsation increases the amount of air in the flame, Chemical reaction rate; pulsed combustion reduces the reaction area, shorten the gas residence time in the high temperature region, making NO_x generation small.