The Problems of the Turbulent Burning Velocity
The Problems of the Turbulent Burning Velocity
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湍流燃烧速度问题
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
M. S. Mansour
中科院分区：
文献类型：
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作者：
D. Bradley;M. Lawes;M. S. Mansour
本文综述了紊流燃烧速度测量中的实际问题，给出了燃烧质量率。这些主要集中在确定一个适当的火焰表面，以联系湍流燃烧速度，ut和未燃烧混合物的密度。用平均反应过程变量$ar {c}$确定了在风机搅拌弹中爆炸火焰传播的火焰面。对$ar {c}$的测量可以从关系${it Sigma} =kar {c}左（{1-ar {c}}右）$中估计火焰表面密度Σ。结果表明，在这种爆炸中，由测量的总火焰表面积得到的燃烧质量率与由测量的湍流燃烧速度得到的燃烧质量率吻合得很好。小火焰考虑确定适当的无因次相关参数。结果，对于火焰应变率Masr的Markstein数的不同值，湍流燃烧速度除以有效均方根湍流速度的相关性与湍流Karlovitz拉伸因子K的关系被绘制出来。这些图涵盖了广泛的变量，包括压力和燃料，并表明了不同的湍流燃烧制度。在较低的K值下，由于火焰不稳定引起的高频火焰表面起皱，有一些证据表明ut和K增加。这些随着Masr变得更负而增加。从整个火焰刷的平均火焰表面密度的发展值可以发现，在第一个近似上，对于给定的混合物，ut的增加伴随着刷子体积的成比例的增加。分析表明，发生反应的湍流火焰刷的体积分数很小。
The paper reviews the practical problems in measuring a turbulent burning velocity that gives the mass rate of burning. These largely centre on identifying an appropriate flame surface to associate with the turbulent burning velocity, ut, and the density of the unburned mixture. Such a flame surface has been identified, in terms of the mean reaction progress variable, $ar {c}$, for explosive flame propagation in a fan-stirred bomb. Measurement of $ar {c}$ makes possible an estimation of the flame surface density, Σ, from the relationship ${it Sigma} =kar {c}left( {1-ar {c}}
ight)$. It is shown that in such explosions, mass rates of burning derived from the measured total flame surface area agreed well with those found from the measured turbulent burning velocity. Flamelet considerations identify appropriate dimensionless correlating parameters for ut. As a result, correlations of turbulent burning velocity divided by the effective rms turbulent velocity, are plotted against the turbulent Karlovitz stretch factor, K, for different values of the Markstein number for flame strain rate, Masr. These plots cover a wide range of variables, including pressure and fuels, and are indicative of different regimes of turbulent combustion. At the lower values of K, there is some evidence of increases in ut and k due to high-frequency flame surface wrinkling arising from flame instabilities. These increase as Masr becomes more negative. It is found from the developed value of the mean flame surface density throughout the flame brush that, to a first approximation, an increase in ut for a given mixture is accompanied by a proportional increase in the volume of the brush. The analysis shows that the volume fraction of the turbulent flame brush that is reacting is quite small.