Premixed methane–air turbulent flame is generated in a single-nozzle jet-stabilized combustor designed based on the FLOX^® concept¹. Confinement-induced, self-sustained jet oscillation is observed. Its influence on combustion stability near lean blow-out (LBO) is investigated using simultaneous particle imaging velocimetry (PIV), planar laser-induced fluorescence of OH radicals (OH PLIF), and OH chemiluminescence imaging at 5-kHz repetition rate. Via proper orthogonal decomposition (POD) of the velocity field and extended POD of the scalar fields, pronounced variations in the flame shape are observed during a cycle of jet oscillation. In extreme cases, flame is partially blown out in the combustor due to jet impingement on the wall during the first half of its oscillation cycle. In the subsequent half cycle following jet detachment, flame is restabilized after robust flashback and re-light. Statistical analysis shows that such pattern is by far the most prevalent mechanism for blow-out and restabilization to take place at the operating condition. Additionally, these events are found with much higher probability during slow-paced jet oscillations.

预混甲烷-空气湍流火焰在单喷嘴喷射稳定的燃烧器产生的设计的基础上，FLOX ^®概念¹。观察到局限性诱发的，自我维持的射流振荡。使用同步粒子成像测速仪（PIV），平面激光诱导的OH自由基荧光（OH PLIF）和OH化学发光成像（重复频率为5 kHz）研究了其对稀薄吹气（LBO）附近燃烧稳定性的影响。通过速度场的适当正交分解（POD）和标量场的扩展POD，可以在喷射振荡的周期内观察到火焰形状的明显变化。在极端情况下，由于在燃烧室的振荡周期的前半段中，射流撞击在燃烧室上，火焰在燃烧室中被部分吹出。在射流脱离后的下一个半周期中，在强劲的反吹和重新点燃后，火焰会恢复稳定。统计分析表明，到目前为止，这种模式是在运行条件下发生爆裂和再稳定化的最普遍机制。此外，在慢节奏的射流振荡期间，发现这些事件的可能性要高得多。