Experimental Investigation of the Transition Mechanism From Stable Flame to Flashback in a Generic Premixed Combustion System With High-Speed Micro-PIV and Micro-PLIF Combined With Chemiluminescence Imaging
Experimental Investigation of the Transition Mechanism From Stable Flame to Flashback in a Generic Premixed Combustion System With High-Speed Micro-PIV and Micro-PLIF Combined With Chemiluminescence Imaging
复制标题
高速Micro-PIV和Micro-PLIF结合化学发光成像的通用预混燃烧系统从稳定火焰到回火的过渡机制的实验研究
DOI：
10.1115/gt2015-42605
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发表时间：
2015
影响因子：
4.4
通讯作者：
T. Sattelmayer
中科院分区：
文献类型：
--
作者：
G. Baumgartner;L. R. Boeck;T. Sattelmayer
可持续发电导致二氧化碳和氮氧化物等污染物排放量较低，在不久的将来是一项非常具有挑战性的任务。燃气轮机中富氢燃料的预混合燃烧是应对日益严格的排放水平法规的一种有前途的方法。然而，这种方法存在火焰从所需火焰位置回火到预混合部分的风险，从而导致并非针对如此高温设计的机器部件发生灾难性故障。当前研究的目的是可视化并描述一般氢气-空气燃烧系统中从稳定火焰到回火的过渡，并开发一个基于物理的模型来描述该过渡。为了实现捕获相关效应所需的高时间和空间分辨率，采用了高速粒子图像测速（PIV）和高速平面激光诱导荧光（PLIF）。为了详细表征火焰与流动的相互作用，两种测量技术都使用（UV）长距离显微镜应用于非常小的视场。 PLIF 的重复率为 20 kHz，PIV 的重复率为 3 kHz。在 PLIF 和 PIV 测量过程中，从垂直于 PLIF/PIV 相机视角的角度捕获火焰的 OH*-化学发光，以进一步表征火焰。微观测量表明，在稳定模式下，无约束火焰对燃烧器进入流量的影响可以忽略不计。然而，在接近闪回条件时，燃烧器流的速度分布由于预混合管道内火焰的存在而明显扭曲。直接位于火焰上游的气流被阻滞并在引导火焰尖端周围偏转。根据实验中观察到的效果，提出了一种新的闪回模型，该模型将向燃烧器边缘的传热和火焰速度确定为闪回发生的主要驱动因素，而火焰背压是随后上游火焰传播的控制因素。版权所有 © 2015 by ASME
Sustainable power generation resulting in low pollutant emissions, such as CO2 and NOx, poses a very challenging task in the near future. Premixed combustion of hydrogen-rich fuels in gas turbines is a promising approach to cope with ever more stringent regulations on emission levels. This method, however, involves the risk of flame flashback from the desired flame position into the premixing section, leading to catastrophic failure of the machine components that are not designed for such high temperatures. The objective of the current study was to visualize and describe the transition from stable flame to flashback in a generic H2-air combustion system and develop a physics-based model for the description of the transition. In order to achieve the high temporal and spatial resolution required for capturing the involved effects, high-speed Particle Image Velocimetry (PIV) and high-speed Planar Laser-Induced Fluorescence (PLIF) were employed. In order to characterize the interaction of the flame with the flow in detail, both measurement techniques were applied to very small fields-of-view using (UV) long-distance microscopes. The repetition rates were 20 kHz for PLIF and 3 kHz for PIV, respectively. During both the PLIF and the PIV measurements, the flame’s OH*-chemiluminescence was captured from a perspective perpendicular to that of the PLIF/PIV camera for further flame characterization. The microscopic measurements revealed that there is negligible influence of the unconfined flame on the incoming burner flow in stable mode. Upon approaching flashback conditions, however, the velocity profile of the burner flow is distinctly distorted by the presence of the flame inside the premixing duct. The flow directly upstream of the flame is retarded and deflected around the leading flame tip. Based on the effects observed in the experiments, a new flashback model is proposed, which identifies the heat transfer to the burner rim and the flame speed as the main drivers for the onset of flashback, whereas the flame backpressure is the governing factor for the subsequent upstream flame propagation.Copyright © 2015 by ASME