Rayleigh Index Fields in Helically Perturbed Swirl-Stabilized Flames Using Doubly Phase Conditioned OH* Chemiluminescence Tomography
Rayleigh Index Fields in Helically Perturbed Swirl-Stabilized Flames Using Doubly Phase Conditioned OH* Chemiluminescence Tomography
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DOI：
10.1007/s10494-016-9727-4
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
B. D. Geraedts;C. Arndt;A. Steinberg
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文献类型：
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作者：
B. D. Geraedts;C. Arndt;A. Steinberg
本文介绍了一种计算热声能量传递的方法。使用高重复频率的OH*化学发光测量，在具有不对称3D流动结构的复杂旋涡稳定火焰中的场(瑞利指数)。测量是在各种完全预混的甲烷-空气火焰中获得的，每个火焰都包含一个螺旋速度扰动，并与一个进动涡核(PVC)相耦合。通过跟踪化学发光质心的位置来确定聚氯乙烯的方位位置和相对于视角的螺旋扰动。然后对多相条件平均化学发光场进行层析重建，以确定热声循环中不同阶段螺旋扰动热释放场的平均3D形状。这些场与测量的压力信号相结合，可以计算热声能量传递分布。发现了复杂的模式，通常涉及燃烧器外围(即向外回流区)的相当大的能量转移。总能量传递与极限环振荡幅度成比例关系。该方法为确定驱动热声振荡的燃烧室区域提供了一种相对简单和稳健的诊断方法。
This paper demonstrates a method for calculating thermoacoustic energy transfer (viz. Rayleigh Index) fields in complex swirl-stabilized flames having asymmetric 3D flow structures using high-repetition-rate OH* chemiluminescence measurements. Measurements were acquired in a variety of perfectly premixed methane-air flames, each of which contained a helical velocity disturbance that was coupled with a precessing vortex core (PVC). The azimuthal position of the PVC and helical disturbance relative to the viewing angle was determined by tracking the position of the chemiluminescence centoid. Tomographic reconstruction of multiply-phase-conditioned mean chemiluminescence fields then was performed to determine the mean 3D shape of the helically-perturbed heat release field at different phases over the thermoacoustic cycle. These fields, in combination with measured pressured signals, allowed calculation of the thermoacoustic energy transfer distribution. Complex patterns were found, which generally involved considerable energy transfer in the periphery of the burner (i.e. towards the outer recirculation zone). The total energy transfer was found to scale with the limit-cycle oscillation amplitude. This method provides a relatively simple and robust diagnostic for determining combustor regions driving thermoacoustic oscillations.