Transfer functions of laminar premixed flames subjected to forcing by acoustic waves, AC electric fields, and non-thermal plasma discharges
Transfer functions of laminar premixed flames subjected to forcing by acoustic waves, AC electric fields, and non-thermal plasma discharges
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DOI：
10.1016/j.proci.2016.05.034
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
D. Lacoste;Y. Xiong;J. Moeck;S. Chung;W. Roberts;M. Cha
中科院分区：
文献类型：
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作者：
D. Lacoste;Y. Xiong;J. Moeck;S. Chung;W. Roberts;M. Cha
本文报道了层流甲烷-空气火焰对声波、交流电场和纳秒重复脉冲（NRP）辉光放电的响应。实验装置包括一个轴对称燃烧器和一个由石英管制成的喷嘴。研究了三种不同的火焰几何形状：锥形、m形和v形火焰。中心的不锈钢棒用作电场和等离子体激励的阴极。声强迫是由位于燃烧器底部的扬声器获得的。对于交流电场的强迫，在棒的上方放置一个金属栅格，并连接到交流电源。等离子体强迫是通过在杆和放置在石英管出口的环形不锈钢环之间施加10ns持续时间的10khz高压脉冲来获得的。用CH*的化学发光来测定放热速率波动。对于声波和等离子体强迫，火焰的几何形状对燃烧的响应起关键作用，而火焰的形状对燃烧对电场强迫的响应没有影响。火焰对约10%来流声强迫的响应与文献中得到的结果相似。火焰被发现对整个频率范围内的交流电场有反应。提出了一种基于离子风产生的强迫机制。发现等离子体强迫获得的传递函数增益比声强迫高5倍。介绍了一种可能的等离子体强迫机制。
The responses of laminar methane–air flames to forcing by acoustic waves, AC electric fields, and nanosecond repetitively pulsed (NRP) glow discharges are reported here. The experimental setup consists of an axisymmetric burner with a nozzle made from a quartz tube. Three different flame geometries have been studied: conical, M-shaped and V-shaped flames. A central stainless steel rod is used as a cathode for the electric field and plasma excitations. The acoustic forcing is obtained with a loudspeaker located at the bottom part of the burner. For forcing by AC electric fields, a metallic grid is placed above the rod and connected to an AC power supply. Plasma forcing is obtained by applying high-voltage pulses of 10-ns duration applied at 10 kHz, between the rod and an annular stainless steel ring, placed at the outlet of the quartz tube. The chemiluminescence of CH*is used to determine the heat release rate fluctuations. For forcing by acoustic waves and plasma, the geometry of the flame plays a key role in the response of the combustion, while the flame shape does not affect the response of the combustion to electric field forcing. The flame response to acoustic forcing of about 10% of the incoming flow is similar to those obtained in the literature. The flames are found to be responsive to an AC electric field across the whole range of frequencies studied. A forcing mechanism, based on the generation of ionic wind, is proposed. The gain of the transfer function obtained for plasma forcing is found to be up to 5 times higher than for acoustic forcing. A possible mechanism of plasma forcing is introduced.