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为了更深入地理解民用航空发动机低排放燃烧室中的同心旋流分层火焰脉动机制,以丙烷为燃料,在100Hz频率的外激条件下对该类旋流火焰的CH~*化学发光图像进行高频采样,重点通过本征正交分解法(POD)的统计学分析,提取其时间和空间域内的脉动特征。分析结果表明,旋流火焰中4个最主要的脉动模态分别是轴向振荡、径向振荡、火焰脱落和非对称螺旋运动,并且模态1轴向振荡和模态2径向振荡之间具有显著相关性。POD分析方法可作为中心分级贫油预混燃烧不稳定性机理探索的有效手段。
In order to better understand the concentric swirling stratified flame pulsation mechanism in low-emission combustion chambers of civil aero-engines, CH ~ * chemiluminescence images of such swirling flames were carried out with propane as fuel under external excitation at a frequency of 100 Hz High-frequency sampling, focusing on the adoption of the eigen-orthogonal decomposition (POD) statistical analysis, to extract its time and space domain pulse characteristics. The analysis results show that the four main modes of pulsation are axial oscillation, radial oscillation, flaming off and asymmetric spiral motion, and the difference between the mode 1 axial oscillation and the mode 2 radial oscillation There is a significant correlation. POD analysis method can be used as an effective means to explore the instability mechanism of lean-burn premixed combustion.