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Soot formation in annular non-premixed laminar flames of methane-air at pressures of 0.1 to 4.0 MPa.

机译：在0.1到4.0 MPa的压力下，在甲烷-空气的环状非预混合层流火焰中形成烟灰。

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摘要

Laminar non-premixed methane-air flames were studied over the pressure range of 0.5 to 4.0 MPa using a new high pressure combustion chamber. Flame characterization showed very good flame stability over the range of pressures, with flame tip rms flicker of less than 1% in flame height. At all pressures, soot is completely oxidized within the visible flames and the maximum optical thickness observed was 0.51. Spectral soot emission (SSE) and line-of-sight attenuation (LOSA) measurements provided radially resolved soot volume fraction and soot temperature at pressures from 0.5 to 4.0 MPa. Such measurements provide an improved understanding of the influence of pressure on soot formation and have not been obtained previously in laminar non-premixed flames for pressures above 0.4 MPa. The total uncertainty of the LOSA soot volume fraction measurements is estimated to be 20--30% (95% confidence interval). The total uncertainty of the SSE soot temperature measurements is estimated to be 3.5% and the total uncertainty of the SSE soot volume fraction measurements is estimated to be 35--40%. SSE and LOSA measurements of soot concentration typically agree to within 30% and both methods exhibit similar trends in the spatial distribution of soot concentration. Maximum soot concentration variation with pressure is described by a power law, where the exponent on pressure is about 2 for the range of pressures between 0.5 MPa and 2.0 MPa, and about 1.2 for pressures of 2.0 MPa to 4.0 MPa. The pressure dependence of peak carbon conversion to soot is also well described by a power-law relationship, where the pressure exponent is unity for pressures between 0.5 MPa and 2.0 MPa and 0.1 for 2.0 MPa to 4.0 MPa. The pressure dependence of sooting propensity diminished at pressures above 2.0 MPa. Soot concentration measured in this work, when transformed to line-integrated values, are consistent with measurements of line-integrated soot volume fraction available in the literature. Soot temperature measurements indicate that the overall, temperature at a given height above the nozzle exit of the burner decrease with increasing pressure; however, the differences across pressures diminish with increasing height in the flame. Low down in the flame, temperatures are about 150 K lower at pressures of 4.0 MPa than those at 0.5 MFa. In the upper half of the flame the differences reduce to 50 K.
机译：使用新的高压燃烧室在0.5至4.0 MPa的压力范围内研究了层状非预混甲烷-空气火焰。火焰表征在压力范围内显示出非常好的火焰稳定性，火焰尖端均方根闪烁在火焰高度上小于1％。在所有压力下，烟灰在可见火焰中被完全氧化，观察到的最大光学厚度为0.51。光谱烟尘排放（SSE）和视线衰减（LOSA）测量提供了在0.5至4.0 MPa压力下的径向烟尘体积分数和烟尘温度。这样的测量可以更好地理解压力对烟formation形成的影响，并且以前在层状非预混火焰中对于压力高于0.4 MPa尚未获得。 LOSA烟尘体积分数测量的总不确定度估计为20--30％（95％置信区间）。 SSE烟灰温度测量的总不确定度估计为3.5％，SSE烟灰体积分数测量的总不确定度估计为35--40％。烟尘浓度的SSE和LOSA测量值通常在30％之内，并且两种方法在烟尘浓度的空间分布中都显示出相似的趋势。最大烟灰浓度随压力的变化由幂定律描述，其中在0.5 MPa至2.0 MPa之间的压力范围内，压力指数约为2，而在2.0 MPa至4.0 MPa的压力下指数约为1.2。碳峰转化为烟灰的压力依赖性也可以通过幂律关系很好地描述，其中幂指数对于0.5 MPa至2.0 MPa之间的压力是统一的，而对于2.0 MPa至4.0 MPa的压力则是0.1。在高于2.0MPa的压力下，烟ing倾向的压力依赖性减小。这项工作中测得的烟灰浓度，当转换为线积分值时，与文献中可获得的线积分烟灰体积分数的测量结果一致。烟尘温度测量表明，燃烧器喷嘴出口上方给定高度的总体温度随着压力的增加而降低；但是，压力的差异随着火焰高度的增加而减小。火焰低落，在4.0 MPa的压力下温度比在0.5 MFa的温度低约150K。在火焰的上半部分，差异减小到50K。

著录项

  • 作者

    Thomson, Kevin A.;

  • 作者单位

    University of Waterloo (Canada).;

  • 授予单位 University of Waterloo (Canada).;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 296 p.
  • 总页数 296
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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