激光诱导击穿光谱法研究低放热率火焰的稳定性

IF 2.8 2区工程技术 Q2 ENGINEERING, MECHANICAL

Experimental Thermal and Fluid Science Pub Date : 2024-12-06 DOI:10.1016/j.expthermflusci.2024.111386

Ching-Kang Huang , Jun Hayashi , Takahiro Sako , Hiroshi Kawanabe , Masashi Katsuki

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引用次数: 0

摘要

本研究研究了燃烧器边缘厚度对低热释放率（HRR）非预混射流火焰稳定特性的影响，这对于扩大低热释放率燃料（如氨）在实际燃烧器中的应用至关重要。火焰的HRR是一个重要的参数，因为HRR和热损失率的平衡影响火焰的稳定性。在本研究中，低HRR燃料采用CH4-N2混合物进行模拟，其火焰在不同边缘厚度的四槽燃烧器上方形成。OH*化学发光成像表明，燃料中CH4含量较低的火焰在较薄边缘上方的三重火焰结构中升起并稳定；较厚的边缘阻止了火焰的升起，但降低了火焰基部的反应强度。用激光诱导击穿光谱（LIBS）测定了CH4、O2和N2在晶缘附近的摩尔分数分布，并讨论了氮谱线的选择。LIBS结果表明，在较厚的边缘附近，燃料-空气混合更有效。而在较薄边缘以上的火焰基部，物质扩散速度更快，反应强度更高。结果表明，薄轮辋和厚轮辋上的火焰稳定机制可能不同。

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Study on the stability of low heat release rate flames by laser-induced breakdown spectroscopy

This study investigated the effects of burner rim thickness on the stabilization characteristics of non-premixed jet flames with low heat release rate (HRR), which is crucial for expanding the application of low HRR fuels (e.g., ammonia) in practical burners. HRR of a flame is a significant parameter since flame stability is influenced by the balance of HRR and heat loss rate. In this study, low HRR fuels were simulated by CH₄-N₂ mixtures and their flames were formed above a quadruple-slot burner with different rim thicknesses. OH* chemiluminescence imaging showed that flames with low CH₄ content in fuel lifted off and stabilized by triple flame structures above the thinner rim; thicker rim prevented flame liftoff but reduced the reaction intensity at flame bases. Mole fraction distributions of CH₄, O₂ and N₂ in the vicinity of the rims were measured by laser-induced breakdown spectroscopy (LIBS), and the appropriate choice of nitrogen spectral lines was discussed. LIBS results indicated that fuel–air mixing was more effective near the thicker rim. However, species diffusion at the flame bases above the thinner rim was faster, resulting in higher reaction intensity. The results suggest that the flame stabilization mechanism above thinner rims and thicker rims may be different.

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来源期刊

Experimental Thermal and Fluid Science 工程技术-工程：机械

CiteScore

6.70

自引率

3.10%

发文量

159

审稿时长

34 days

期刊介绍： Experimental Thermal and Fluid Science provides a forum for research emphasizing experimental work that enhances fundamental understanding of heat transfer, thermodynamics, and fluid mechanics. In addition to the principal areas of research, the journal covers research results in related fields, including combined heat and mass transfer, flows with phase transition, micro- and nano-scale systems, multiphase flow, combustion, radiative transfer, porous media, cryogenics, turbulence, and novel experimental techniques.