Jet flame heights, lift-off distances, and mean flame surface density for extensive ranges of fuels and flow rates
Jet flame heights, lift-off distances, and mean flame surface density for extensive ranges of fuels and flow rates
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DOI：
10.1016/j.combustflame.2015.09.009
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发表时间：
2016-02-01
影响因子：
4.4
通讯作者：
Palacios, Adriana
中科院分区：
文献类型：
--
作者：
Bradley, Derek;Gaskell, Philip H.;Palacios, Adriana
对射流火焰高度和结构进行了广泛的回顾和重新思考，扩展到窒息/超音速状态，并讨论了以前火焰高度相关性的局限性。在没有横风的情况下，提出了全新的羽流高度、升空距离和大气喷射火焰平均火焰表面密度的无量纲相关性。研究发现，相同的流量参数可以用于羽流高度和火焰起飞距离的关联。这些与火焰结构、射流火焰不稳定性和火焰熄灭拉伸率有关，这是通过补充实验和计算研究揭示的。这些相关性是基于覆盖880个火焰高度的庞大实验数据库得出的。它们包括池火和火焰，以及CH4， C2H2, C2H4, C3H8， C4H10和H-2的窒息和未窒息喷射火焰，在各种条件下。供应压力范围从0.06到90mpa，排放直径从4 × 10（-4）到1.32米，火焰高度从0.08到110米。计算研究可以估计反应区体积占羽流体积的比例，这是根据火焰照片和温度等高线测量的。这样就可以估计平均火焰表面密度，以及平均体积热释放率。有证据表明，“饱和”平均表面密度和湍流燃烧速率的增加是通过反应混合物总体积的接近成比例的增加来实现的。(C) 2015燃烧研究所。Elsevier Inc.出版。版权所有。
An extensive review and re-thinking of jet flame heights and structure, extending into the choked/supersonic regime is presented, with discussion of the limitations of previous flame height correlations. Completely new dimensionless correlations for the plume heights, lift-off distances, and mean flame surface densities of atmospheric jet flames, in the absence of a cross wind, are presented. It was found that the same flow rate parameter could be used to correlate both plume heights and flame lift-off distances. These are related to the flame structure, jet flame instability, and flame extinction stretch rates, as revealed by complementary experiments and computational studies. The correlations are based on a vast experimental data base, covering 880 flame heights. They encompass pool fires and flares, as well as choked and unchoked jet flames of CH4, C2H2, C2H4, C3H8, C4H10 and H-2, over a wide range of conditions. Supply pressures range from 0.06 to 90 MPa, discharge diameters from 4 x 10(-4) to 1.32 m, and flame heights from 0.08 to 110 m. The computational studies enabled reaction zone volumes to be estimated, as a proportion of the plume volumes, measured from flame photographs, and temperature contours. This enabled mean flame surface densities to be estimated, together with mean volumetric heat releases rates. There is evidence of a "saturation" mean surface density and increases in turbulent burn rates being accomplished by near pro rata increases in the overall volume of reacting mixture. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.