Reynolds number scaling of burning rates in spherical turbulent premixed flames
Reynolds number scaling of burning rates in spherical turbulent premixed flames
复制标题
球形湍流预混火焰中燃烧速率的雷诺数缩放
DOI：
10.1017/jfm.2020.784
复制
发表时间：
2021
影响因子：
3.7
通讯作者：
Bisetti, Fabrizio
中科院分区：
文献类型：
--
作者：
Kulkarni, Tejas;Buttay, Romain;Kasbaoui, M. Houssem;Attili, Antonio;Bisetti, Fabrizio
在湍流预混燃烧的小火焰区，燃烧速率的提高主要来源于表面扰动。在这项工作中，我们研究了衰减各向同性湍流中的球形湍流甲烷/空气预混火焰燃烧速率的雷诺数依赖性的直接数值模拟。通过改变雷诺数进行了几次模拟，同时保持Karlovitz数相同，火焰表面的时间演化进行比较，通过结合火焰表面从原点的径向距离的概率密度函数与表面密度函数形式主义。由于由半径等于平均火焰半径的球体面积归一化的褶皱火焰表面的平均面积与湍流火焰刷厚度和刷内的峰值表面密度的乘积成比例，因此分别研究了刷和峰值表面密度的时间演化。刷的厚度示出的流动的整体规模的规模，由于衰减的速度波动和拉伸的演变。当通过积分尺度进行归一化时，定义为峰值表面密度的倒数的湍流尺度示出为在整个模拟和湍流衰减中与雷诺数成比例。其结果是，面积比和燃烧速率被发现增加，与最近的球形湍流预混火焰的实验。我们观察到，当雷诺数保持不变时，面积比不随湍流强度而变化。
In the flamelet regime of turbulent premixed combustion the enhancement in the burning rates originates primarily from surface wrinkling. In this work we investigate the Reynolds number dependence of burning rates of spherical turbulent premixed methane/air flames in decaying isotropic turbulence with direct numerical simulations. Several simulations are performed by varying the Reynolds number, while keeping the Karlovitz number the same, and the temporal evolution of the flame surface is compared across cases by combining the probability density function of the radial distance of the flame surface from the origin with the surface density function formalism. Because the mean area of the wrinkled flame surface normalized by the area of a sphere with radius equal to the mean flame radius is proportional to the product of the turbulent flame brush thickness and peak surface density within the brush, the temporal evolution of the brush and peak surface density are investigated separately. The brush thickness is shown to scale with the integral scale of the flow, evolving due to decaying velocity fluctuations and stretch. When normalized by the integral scale, the wrinkling scale defined as the inverse of the peak surface density is shown to scale with Reynolds number across simulations and as turbulence decays. As a result, the area ratio and the burning rate are found to increase as , in agreement with recent experiments on spherical turbulent premixed flames. We observe that the area ratio does not vary with turbulent intensity when holding the Reynolds number constant.
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DOI：
10.1016/s0082-0784(77)80450-5
发表时间：
1977
期刊：
--
影响因子：
--
作者：
R. Abdel-Gayed;D. Bradley
通讯作者：
R. Abdel-Gayed;D. Bradley
预混湍流燃烧中的通过时间和小焰交叉频率
影响因子：
1.9
作者：
K. Bray;P. Libby
通讯作者：
P. Libby
密闭容器中预混湍流燃烧的应变层流火焰计算
DOI：
--
发表时间：
1989
期刊：
影响因子：
--
作者：
R. Cant;K. Bray
通讯作者：
K. Bray
影响因子：
4.6
作者：
N. Chakraborty;R. Cant
通讯作者：
N. Chakraborty;R. Cant
力学调查
影响因子：
1.8
作者：
G. Batchelor;R. M. Davies;A. Beiser
通讯作者：
A. Beiser