The flow field structure for aero-engine combustor is one of the most important factors for combustion performance. To investigate how the rotating direction of dual-axial swirlers affects the flow field and combustion characteristics, particle image velocimetry (PIV) experiments were conducted in the primary combustion and intermediate zones. Additionally, planar laser induced fluorescence (PLIF) was used to map the distribution of kerosene and OH in the primary combustion zone. The results show that the swirling jets in co-swirl exhibit greater jet momentum, resulting in a longer primary recirculation zone and a larger deflection angle of the primary jets. This ultimately leads to a higher recirculation rate compared to counter-swirl. The primary jets define the boundary of the flow field structure. The rotating direction primarily affects the flow field structure upstream of the primary jets, exerts a relatively weaker influence on the intermediate zone, which is mainly affected by the deflection direction of the primary jets, and essentially has no impact on the dilution jets. Co-swirl has a relatively stable flow field than counter-swirl, whereas the flow field in counter-swirl is more chaotic, featuring a greater number of vortex cores in the primary recirculation zone. The coupling between the primary and swirling jets affects the mass transfer direction in the intermediate zone, which is reflected in the fact that the mass transfer is from top-left to bottom-right in co-swirl, while it is in the opposite direction in counter-swirl. OH is predominantly found in the swirling shear layers, the primary and secondary combustion zones, whereas kerosene is mainly concentrated in the shear layers of swirling jets. The kerosene distribution in co-swirl shows a larger and more concentrated expansion angle compared to counter-swirl. In contrast, the OH distribution downstream of counter-swirl is broader, with more intense combustion due to enhanced kerosene decomposition and fuel-air mixing. The smaller primary recirculation zone in counter-swirl forces the primary combustion zone to extend downstream, leading to a more intense reaction in the secondary recirculation zone.

中文翻译：

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双轴旋流器旋转方向对航空发动机燃烧室流场及燃烧特性的实验研究


航空发动机燃烧室的流场结构是影响燃烧性能的最重要因素之一。为了研究双轴旋流器的旋转方向如何影响流场和燃烧特性，在主燃烧区和中间区进行了粒子图像测速（PIV）实验。此外，平面激光诱导荧光 (PLIF) 用于绘制主燃烧区煤油和 OH 的分布图。结果表明，同旋的旋流射流表现出更大的射流动量，导致主再循环区更长，主射流的偏转角更大。与反旋流相比，这最终导致更高的再循环率。主射流限定了流场结构的边界。旋转方向主要影响主射流上游的流场结构，对中间区影响相对较弱，主要受主射流偏转方向影响，对稀释射流基本没有影响。与逆涡流相比，同旋流场具有相对稳定的流场，而逆涡流流场更加混乱，在一次再循环区具有更多数量的涡核。主射流与旋流射流之间的耦合影响了中间区的传质方向，体现在同旋射流中传质方向是从左上到右下，而在中间区传质方向相反。反漩涡。 OH主要存在于旋流剪切层、初级和次级燃烧区，而煤油主要集中在旋流射流的剪切层中。 与反旋流相比，同旋流中的煤油分布显示出更大且更集中的扩展角。相比之下，反旋流下游的 OH 分布更广泛，由于煤油分解和燃料-空气混合的增强，燃烧更剧烈。反涡流中较小的初级再循环区迫使初级燃烧区向下游延伸，导致次级再循环区发生更强烈的反应。