Investigating the effect of local addition of hydrogen to acoustically excited ethylene and methane flames
Investigating the effect of local addition of hydrogen to acoustically excited ethylene and methane flames
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DOI：
10.1016/j.ijhydene.2019.02.182
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发表时间：
2019-04-23
影响因子：
7.2
通讯作者：
Balachandran, Ramanarayanan
中科院分区：
文献类型：
--
作者：
Hussain, Taaha;Talibi, Midhat;Balachandran, Ramanarayanan
虽然已知燃气轮机中的稀薄燃烧可减少NOx，但其使燃烧器更易于发生热声不稳定性，这可导致发动机性能的劣化。本文研究了二次注入氢气对不完全预混的甲烷和乙烯火焰在减少放热振荡方面的有效性。研究了声学强迫和非强迫火焰，并同时进行了OH和H原子PLIF（平面激光诱导荧光）。试验是在一台带有中心V形海崖体的实验室钝体燃烧室上进行的。采用双传声器法从压力测量中估计速度扰动，采用高速Mie散射获取火焰边界图像，同时通过OH* 化学发光确定全局放热波动，结果表明，除了甲烷火焰在315 Hz的强迫频率下，氢气的加入显著降低了甲烷和乙烯火焰在所有强迫频率下的放热波动，其中振荡随着氢的加入而增加。氢气的加入降低了甲烷和乙烯火焰的火焰卷起的程度，然而，这种减少甲烷火焰更大。NOx废气排放量增加，观察到氢气除了甲烷和乙烯火焰，与绝对NOx浓度较高的乙烯火焰，由于较高的火焰温度。(C)2019年氢能出版有限责任公司。由爱思唯尔有限公司出版。保留所有权利。
While lean combustion in gas turbines is known to reduce NOx, it makes combustors more prone to thermo-acoustic instabilities, which can lead to deterioration in engine performance. The work presented in this study investigates the effectiveness of secondary injection of hydrogen to imperfectly premixed methane and ethylene flames in reducing heat release oscillations. Both acoustically forced and unforced flames were studied, and simultaneous OH and H atom PLIF (planar laser induced fluorescence) was conducted. The tests were carried out on a laboratory scale bluff-body combustor with a central V-shaped bluff body. Two-microphone method was used to estimate velocity perturbations from pressure measurements, flame boundary images were captured using high speed Mie scattering, while global heat release fluctuations were determined from OH* chemiluminescence.The results showed that hydrogen addition considerably reduced heat release oscillations for both methane and ethylene flames at all the forcing frequencies tested, with the exception of methane flames forced at 315 Hz, where oscillations increased with hydrogen addition. The addition of hydrogen reduced the extent of flame roll-up for both methane and ethylene flames, however, this reduction was larger for methane flames. NOx exhaust emissions were observed to increase with hydrogen addition for both methane and ethylene flames, with absolute NOx concentrations higher for ethylene flames, due to higher flame temperatures. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.