The present work investigated the flame structures and oscillations of oxy-fuel combustions in a heavy oil boiler using OH planar laser-induced fluorescence imaging. Combustion instabilities, such as flame oscillation and combustion fluctuation, can assess the performance of an industrial burner in the boiler. The peak position variation in OH concentration was associated with the change of the reaction zone that corresponded with the fluctuation of the heat-release zone in the combustion chamber, which provides a valuable reference for the design of the combustion chamber. The experimental results suggest that the phenomenon of stratified flame combustion is related to the characteristic of flame oscillation. The substitution of N₂ with CO₂ will not significantly influence the flame oscillation frequency but increases the number of flame surface. As O₂ concentration increased in the O₂/CO₂ atmosphere, the phenomenon of stratified flame combustion disappeared, and the flame presented an island-like structure. The bimodal oscillation of the combustion center was demonstrated by means of the probability density method; CO₂ played a role in the extension of the combustion center. The combustion fluctuation of inner regions was quantitatively described; CO₂ could maintain interregional stabilization to some extent. Compared with traditional measurement methods, PLIF technology has great advantages in evaluating burner performance and optimizing the design of the combustion chamber.

中文翻译：

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OH平面激光诱导荧光在重油锅炉中氧燃料火焰振荡特性的统计分析

本工作使用OH平面激光诱导的荧光成像技术研究了重油锅炉中含氧燃料燃烧的火焰结构和振荡。燃烧不稳定性，例如火焰振荡和燃烧波动，可以评估锅炉中工业燃烧器的性能。OH浓度的峰值位置变化与反应区的变化有关，该变化与燃烧室中放热区的波动相对应，这为燃烧室的设计提供了有价值的参考。实验结果表明，分层燃烧现象与火焰振荡特性有关。N ₂被CO ₂取代不会显着影响火焰的振荡频率，但会增加火焰表面的数量。的O ₂浓度在将O增加₂ / CO ₂气氛下，将分层燃烧火焰的现象消失，且火焰呈现的岛状结构。通过概率密度法证明了燃烧中心的双峰振荡。CO ₂在燃烧中心的扩展中发挥了作用。定量描述了内部区域的燃烧波动；一氧化碳₂可以在一定程度上保持区域间的稳定。与传统的测量方法相比，PLIF技术在评估燃烧器性能和优化燃烧室设计方面具有巨大优势。