Heat release rate estimation in laminar premixed flames using laser-induced fluorescence of CH2O and H-atom
Heat release rate estimation in laminar premixed flames using laser-induced fluorescence of CH2O and H-atom
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DOI：
10.1016/j.combustflame.2015.12.023
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发表时间：
2016-03
影响因子：
4.4
通讯作者：
I. Mulla;A. Dowlut;T. Hussain;Z. Nikolaou;S. Chakravarthy;N. Swaminathan;R. Balachandran
中科院分区：
文献类型：
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作者：
I. Mulla;A. Dowlut;T. Hussain;Z. Nikolaou;S. Chakravarthy;N. Swaminathan;R. Balachandran
本工作证明了在层流预混火焰中使用原子氢（H-原子）和甲醛（CH 2 O）的激光诱导荧光（LIF）的热释放率成像的可行性。H原子LIF和CH_2O LIF信号的乘积在逐像素的基础上进行评估，并与OH × CH_2O技术进行比较。当量比范围从0.8到1.1的这些结果进行了比较与一维自由传播火焰的计算。从局部热释放率的空间精度和总热释放率随当量比的变化趋势两个方面对这些标记的性能进行了研究。自由基空间分布的测量趋势和推导的热释放速率与计算值吻合得很好。空间积分的热释放率作为当量比的函数的变化也进行了研究。结果表明，综合热释放率的变化趋势和热释放率的空间位置可以通过这些标志物中的任何一个来评估。与基于H原子的标记物相比，基于OH的标记物显示出对化学机制的一定灵敏度。基于OH和基于H原子的技术都提供了热释放速率的接近估计。与基于H原子的方法相比，基于OH的技术具有实际优势，主要是由于H原子LIF是双光子过程的事实。
The present work demonstrates the feasibility of heat release rate imaging using the laser-induced fluorescence (LIF) of atomic hydrogen (H-atom) and formaldehyde (CH2O) in laminar premixed flames. The product of H-atom LIF and CH2O LIF signals is evaluated on a pixel-by-pixel basis and is compared with that of the OH × CH2O technique. These results for equivalence ratio ranging from 0.8 to 1.1 are compared with computations of one-dimensional freely-propagating flames. The performance of these markers is studied based on the following two aspects: the spatial accuracy of the local heat release rate and the trend in the total heat release rate with equivalence ratio. The measured trend in the spatial distribution of radicals and the deduced heat release rate agree well with the computational values. The variation in the spatially integrated heat release rate as a function of equivalence ratio is also investigated. The results suggest that the trend in the variation of the integrated heat release rate and the spatial location of heat release rate can be evaluated by either of these markers. The OH-based marker showed certain sensitivity to the chemical mechanism as compared to the H-atom based marker. Both the OH-based and H-atom based techniques provide close estimates of heat release rate. The OH based technique has practical advantage when compared to the H-atom based method, primarily due to the fact that the H-atom LIF is a two-photon process.