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采用Rijke型自激式脉动燃烧器,结合纹影摄像,对不同脉动频率、脉动振幅和燃烧功率下的NOx排放量进行了比较和机理分析.结果表明:在试验工况范围内,甲烷自激励脉动燃烧与非脉动燃烧相比可降低NOx的生成,NOx最高降低了99%,对应的CO降低了13.8%;当燃烧功率增大时,会出现燃烧不完全和燃烧效率降低的现象;脉动火焰符合分形特征,其分形维数大于非脉动燃烧,火焰内流场褶皱、卷曲的程度更高;脉动燃烧下NOx降低的原因是掺混程度更好、传热率更高;随着脉动频率的增加,NOx的排放量降低,说明频率增加促进了气体掺混,减少了气体在高温区的停留时间;脉动燃烧下NOx的排放随燃烧功率的增大而升高.
The Rijke self-excited pulsation combustor was used to compare and analyze the NOx emissions at different pulsation frequencies, pulsation amplitudes and combustion powers with the combination of the smear imaging.The results show that under the experimental conditions, methane self-excitation Compared with non-pulsating combustion, pulsatile combustion can reduce the generation of NOx, the highest NOx reduction is 99% and the corresponding CO is reduced by 13.8%; when the combustion power is increased, the incomplete combustion and the decrease of combustion efficiency will occur; and the pulsating flame The fractal dimension is higher than that of non-pulsation combustion and the flow field in the flame is more wrinkled and curled. The reason for the decrease of NOx under pulsed combustion is that the blending degree is better and the heat transfer rate is higher. With the increase of pulsation frequency Increase, NOx emissions decreased, indicating that increased frequency to promote gas mixing, reducing gas residence time in the high temperature zone; pulsatile combustion NOx emissions with the combustion power increases.