Fuel effects on diffusion flames at elevated pressures
Fuel effects on diffusion flames at elevated pressures
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DOI：
10.1016/j.fuel.2008.09.013
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发表时间：
2009-02
期刊：
影响因子：
7.4
通讯作者：
H. G. Darabkhani;J. Bassi;H. Huang;Yang Zhang
中科院分区：
文献类型：
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作者：
H. G. Darabkhani;J. Bassi;H. Huang;Yang Zhang
本研究解决了高达1.6MPa的高压对火焰几何形状和层流扩散火焰的闪烁行为的影响，并特别注意燃料可变性的影响。据观察，火焰特性对燃料类型和压力的反应非常敏感。观察到火焰的形状随着压力而急剧变化。当压力增加时，可见火焰直径减小。火焰的高度首先随压力增加而增加，然后随压力的进一步增加而降低。火焰的横截面积（Acs）显示出与压力的n次方（Acs <$P-n）的平均反比关系，其中对于乙烯火焰n=0.8±0.2，对于甲烷火焰n=0.5±0.1，对于丙烷火焰n=0.6±0.1。结果表明，随着压力的增加，稳定燃烧区明显减小。火焰化学发光的高速成像和功率谱显示，乙烯火焰闪烁至少有三个主导模式，每个与相应的谐波在升高的压力。相比之下，甲烷火焰闪烁一个主频率和多达六个谐波模式在高压。
This study addresses the influence of elevated pressures up to 1.6MPa on the flame geometry and the flickering behavior of laminar diffusion flames and particular attention has been paid to the effect of fuel variability. It has been observed that flame properties respond very sensitively to the fuel types and pressure. The shape of the flame was observed to change dramatically with pressure. When the pressure increases, the visible flame diameter decreases. The height of a flame increases first with pressure and then reduces with the further increase of pressure. The cross-sectional area of the flame (Acs) shows an average inverse dependence on pressure to the power of n (Acs∝P−n), where n=0.8±0.2 for ethylene flame, n=0.5±0.1 for methane flame and n=0.6±0.1 for propane flame. It was observed that the region of stable combustion was markedly reduced as pressure was increased. High speed imaging and power spectra of the flame chemiluminescence reveal that an ethylene flame flickers with at least three dominant modes, each with corresponding harmonics at elevated pressures. In contrast methane flames flicker with one dominant frequency and as many as six harmonic modes at elevated pressures.