【摘要】 为了探究氧燃混合比变化对CH₄/O₂点火性能、点火过程以及火焰结构尺寸的影响规律，开展了CH₄/O₂点火实验研究。考虑到CH基是当CH₄燃料燃烧时发出化学发光信号的主要物种，代表了燃烧化学反应的起点，同样是燃烧火焰结构分布的指标，实验使用了高速摄像加CH基滤光片的方法，拍摄了不同氧燃混合比下的火焰结构。实验结果表明：不同的氧燃混合比条件下点火器附近的流动掺混以及点火燃烧情况有所不同，进而点火延迟时间不同，表现为随着氧燃混合比的增大，燃烧室压强开始建立时间提前，同样点火能量下点火延迟时间缩短；延长阀门开启与点火器开始工作的时间间隔增加了燃烧室内未燃烧气体的质量，导致点火时出现更高的压力峰值，在极端情况下，火焰直接显著膨胀；氧燃混合比对建压过程中火焰结构尺寸的影响较大，主要表现为火焰扩张角度衰减速率随氧燃混合比的增大而增大，不同氧燃混合比下稳定段火焰结构尺寸无明显差异，燃烧稳定性较好。更多还原

【Abstract】 In order to investigate the influence of changes in oxygen fuel mixing ratio on the ignition performance, ignition process and flame structure size, CH₄/O₂ ignition experiments were carried out in this paper. Considering that the CH group is the main species that chemiluminescence signal when CH₄ is burned, representing the start point of combustion chemical reactions and also an indicator of the distribution of combustion flame structure, so the flame structures under different oxygen fuel mixing ratios were photographed by using high-speed camera and CH based filter. The conclusions are as follows: Under different oxygen fuel mixing ratios, the flow mixing and ignition combustion conditions near the igniter vary, resulting in different ignition delay times. This is manifested as the time when the pressure begins to establish increases with the increase of oxygen fuel mixing ratio, and the ignition delay time decreases with the same ignition energy. Extending the time interval between valve opening and igniter operation increases the mass of unburned gas in the combustion chamber, leading to higher pressure peaks during ignition. In extreme cases, the flame directly expands significantly. The oxygen fuel mixing ratio has a great impact on the flame structure size in the pressure building process, which is mainly manifested in that the flame expansion angle and attenuation rate increase with the increase of the oxygen fuel mixing ratio. There is no obvious difference in the flame structure size in the stable section under different oxygen fuel mixing ratios, and the combustion stability is good.更多还原