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Effects of elliptical burner geometry on partially premixed gas jet flames in quiescent surroundings.

机译：椭圆形燃烧器的几何形状对静态环境中部分预混气体喷射火焰的影响。

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摘要

This study is the investigation of the effect of elliptical nozzle burner geometry and partial premixing, both 'passive control' methods, on a hydrogen/hydrocarbon flame. Both laminar and turbulent flames for circular, 3:1, and 4:1 aspect ratio (AR) elliptical burners are considered. The amount of air mixed with the fuel is varied from fuel-lean premixed flames to fuel-rich partially premixed flames. The work includes measurements of flame stability, global pollutant emissions, flame radiation, and flame structure for the differing burner types and fuel conditions. Special emphasis is placed on the near-burner region. Experimentally, both conventional (IR absorption, chemiluminecent, and polarographic emission analysis,) and advanced (laser induced fluorescence, planar laser induced fluorescence, Laser Doppler Velocimetry (LDV), Rayleigh scattering) diagnostic techniques are used. Numerically, simulations of 3-dimensional laminar and turbulent reacting flow are conducted. These simulations are run with reduced chemical kinetics and with a Reynolds Stress Model (RSM) for the turbulence modeling.; It was found that the laminar flames were similar in appearance and overall flame length for the 3:1 AR elliptical and the circular burner. The laminar 4:1 AR elliptical burner flame split into two sub-flames along the burner major axis. This splitting had the effect of greatly shortening the 4:1 AR elliptical burner flame to have an overall flame length about half of that of the circular and 3:1 AR elliptical burner flames. The length of all three burners flames increased with increasing burner exit equivalence ratio.; The blowout velocity for the three burners increased with increase in hydrogen mass fraction of the hydrogen/propane fuel mixture. For the rich premixed flames, the circular burner was the most stable, the 3:1 AR elliptical burner, was the least stable, and the 4:1 AR elliptical burner was intermediate to the two other burners. This order of stability was due to two reasons. The elliptical burners have enhanced turbulence generation that lowers their stability when compared to the circular burner. The 4:1 AR elliptical burner had greater stability due to a greater velocity decay rate and wider OH reaction zones particularly in the region between the two jets.; The 3:1 AR elliptical and circular burners produced similar carbon monoxide and nitric oxide emission indexes over the range of equivalence ratios of 0.55 to 4.0, for laminar flames. (Abstract shortened by UMI.)
机译：这项研究是研究椭圆喷嘴燃烧器的几何形状和部分预混合（这两种“被动控制”方法）对氢/烃火焰的影响。圆形，3：1和4：1长径比（AR）椭圆形燃烧器的层流和湍流火焰都应考虑在内。与燃料混合的空气量从贫燃料的预混合火焰到富燃料的部分预混合火焰不等。这项工作包括针对不同燃烧器类型和燃料条件的火焰稳定性，全球污染物排放，火焰辐射和火焰结构的测量。特别强调的是靠近燃烧器的区域。实验上，既使用了常规的（红外吸收，化学发光和极谱发射分析）诊断技术，又使用了先进的（激光诱导荧光，平面激光诱导荧光，激光多普勒测速（LDV），瑞利散射）诊断技术。在数值上进行了三维层流和湍流反应流的模拟。这些模拟是在降低的化学动力学和湍流建模的雷诺应力模型（RSM）下进行的。发现对于3：1 AR椭圆形燃烧器和圆形燃烧器，层流火焰的外观和总火焰长度相似。层流4：1 AR椭圆形燃烧器火焰沿着燃烧器主轴分成两个子火焰。这种分裂的效果是大大缩短了4：1 AR椭圆形燃烧器火焰，使其总火焰长度约为圆形和3：1 AR椭圆形燃烧器火焰的一半。所有三个燃烧器的火焰长度随着燃烧器出口当量比的增加而增加。三个燃烧器的吹出速度随着氢气/丙烷燃料混合物的氢气质量分数的增加而增加。对于浓的预混火焰，圆形燃烧器最稳定，3：1 AR椭圆形燃烧器最不稳定，而4：1 AR椭圆形燃烧器在其他两个燃烧器中间。这种稳定性的顺序是由于两个原因。与圆形燃烧器相比，椭圆形燃烧器产生的湍流增强，从而降低了其稳定性。 4：1 AR椭圆形燃烧器具有更高的速度衰减率和更宽的OH反应区，尤其是在两个喷嘴之间的区域，因此具有更高的稳定性。 3：3 AR椭圆形和圆形燃烧器在层流火焰的当量比为0.55至4.0的范围内产生了相似的一氧化碳和一氧化氮排放指数。 （摘要由UMI缩短。）

著录项

  • 作者

    Baird, Benjamin.;

  • 作者单位

    The University of Oklahoma.;

  • 授予单位 The University of Oklahoma.;
  • 学科 Engineering Aerospace.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 362 p.
  • 总页数 362
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 航空、航天技术的研究与探索;
  • 关键词

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