| 阳亚红,陶尚青,方俊.甲烷与乙烯低拉伸率驻点扩散火焰近极限燃烧行为表征[J].火灾科学,2025,34(2):77-85. |
| 甲烷与乙烯低拉伸率驻点扩散火焰近极限燃烧行为表征 |
| Characterization of the near-limit burning behaviors of methane and ethylene low stretch rate stagnation-point diffusion flames |
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| DOI：10.3969/j.issn.1004-5309.2025.02.01 |
| 基金项目:国家自然科学基金青年项目(52306172);安徽省自然科学基金青年项目(2308085QE169) |
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| 中文关键词: 甲烷与乙烯 低拉伸率 点火延迟时间 边缘火焰位移速度 熄灭极限 |
| 英文关键词:Methane and ethylene Low stretch rate Ignition delay time Edge flame displacement speed Extinction limit |
| 摘要点击次数: 28 |
| 全文下载次数: 33 |
| 中文摘要: |
| 低拉伸率扩散火焰是微重力火灾中常见的火焰形式,采用大曲率球形多孔燃烧器,建立了常重力下浮力诱导的等效低拉伸率驻点扩散火焰,对甲烷和乙烯两种燃料的近极限燃烧行为进行了表征。两种燃料的点火极限喷射速度均随拉伸率的增大而增大,呈现甲烷大于乙烯的趋势。当喷射速度大于临界值时,两种气体的点火延迟时间均随喷射速度增大而急剧减小。对乙烯周期性不稳定行为边缘火焰动力学位移速度的分析表明,在一个周期内,回退位移速度初期大于前进位移速度,随后回退位移速度逐渐减小,前进位移速度则稍有滞后地增加。两种燃料在近熄灭时,均出现了不稳定现象。对于甲烷,其内部出现孔洞,孔洞逐渐扩张导致火焰熄灭;对于乙烯,其边缘火焰不断回退直至火焰熄灭。两种气体的熄灭极限,均随着拉伸率的增大而增大,呈现甲烷大于乙烯趋势。这项研究可以丰富对低拉伸率驻点扩散火焰的理解,从而更好地服务于微重力火灾安全防控。 |
| 英文摘要: |
| Low-stretch diffusion flames are common in microgravity fires. A buoyancy-induced equivalent low-stretch-rate stagnation-point diffusion flame was established using a large-curvature spherical porous burner in normal gravity. The near-limit burning behaviors of two fuels, methane and ethylene, were characterized. The ignition-limit injection velocities of both fuels increased with the stretch rate, exhibiting a trend where methane had a larger value than ethylene. The ignition delay times of both gases decreased sharply with increasing injection speed when the injection speed exceeded the critical value. Analysis of the kinetic flame displacement velocity at the edge of the cyclic instability behavior of ethylene revealed that the retreat displacement speed was initially greater than the forward displacement speed during a cycle. Subsequently, the retreat displacement speed gradually decreased, while the forward displacement speed increased with a slight lag. Both fuels showed instability at near extinction. For methane, holes appeared inside the flame, gradually expanding, leading to extinction. For ethylene, the edge of the flame continually receded until it was extinguished. The extinction limits of both gases increased with the increase in stretch rate and showed that the trend for methane was larger than that for ethylene. This study can enhance the understanding of low-stretch rate stagnation-point diffusion flames, thereby informing microgravity fire safety prevention and control. |
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