Oscillating flames in open tubes
Oscillating flames in open tubes
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DOI：
10.1016/j.proci.2014.07.052
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
J. Yang;F. Mossa;H. W. Huang;Qian Wang;R. Woolley;Yang Zhang
中科院分区：
文献类型：
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作者：
J. Yang;F. Mossa;H. W. Huang;Qian Wang;R. Woolley;Yang Zhang
当火焰沿着两端开口的管道时，产生火焰必须穿过的自感应波动压力/流场。在这里，燃料丰富（1.1 <λ < 1.4）的丙烷-空气火焰已被拍摄沿沿着20 mm内径的石英管行进。观察到火焰行进中的波动随着火焰传播而增加，在220 Hz下达到±10 mm的最大振荡幅度，随着火焰进一步朝向管的端部行进而衰减。周期性压力梯度对火焰形状的影响可以通过将未燃烧的反应物推入产物中的舌状物以及火焰进入未燃烧的混合物中的相应快速加速来辨别。火焰化学的波动的影响进行了监测，通过捕获的CH 3和C2化学发光使用高速彩色摄像机。观察到的CH 3/C2 3的比例，以减少火焰被拉回燃烧的混合物;和增加时，火焰被向前推。这是一致的整个火焰的进展，即使在火焰位置的小振荡进行了测量。这可能是这种环境中火焰的一个重要特征。
When a flame passes along a tube that is open at both ends a self induced fluctuating pressure/flow field is created which the flame has to traverse. Here fuel rich (1.1 <ϕ< 1.4) propane-air flames have been filmed travelling along a 20 mm internal diameter quartz tube. Fluctuations in the flame’s progression were observed to increase as the flame propagated, achieving a maximum oscillation amplitude of ±10 mm at 220 Hz that decayed as the flame progressed further towards the end of the tube. The impact of the periodic pressure gradients on the flame shape could be discerned with tongues of unburned reactants pushed into the products as well as the corresponding rapid acceleration of the flame into the unburned mixture. The impact of the fluctuations on flame chemistry was monitored by capturing the CH∗and C2chemiluminescence using a high speed colour camera. The CH∗/C2∗ratio was observed to decrease as the flame was pulled back towards the burned mixture; and increased when the flame was pushed forwards. This was consistent throughout the flame progress even when small oscillations in the flame position were measured. This could be a significant feature of flames in this environment.