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首页> 外文期刊>European Journal of Mechanics, B. Fluids >Statistical behaviour of vorticity and enstrophy transport in head-on quenching of turbulent premixed flames
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Statistical behaviour of vorticity and enstrophy transport in head-on quenching of turbulent premixed flames

机译：湍流预混火焰头淬火涡流和敌对运输的统计行为

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摘要

The transport of vorticity and enstrophy in the near-wall region for head-on quenching of turbulent combustion by an isothermal inert wall has been analysed using three-dimensional Direct Numerical Simulation (DNS) data of statistically planar turbulent premixed flames characterised by various global Lewis numbers Le (ranging from 0.8 to 1.2) and turbulence intensities. In all cases the vorticity magnitude shows its maximum value at the wall and the vorticity magnitude drops significantly from the unburned to the burned gas side of the flame-brush. Moreover, the vorticity magnitude shows an increasing trend with decreasing Le, and increasing turbulence intensity. A significant amount of anisotropy has been observed between the vorticity components within the flame-brush and this anisotropy increases as the wall is approached. The baroclinic torque term has been found to be principally responsible for this anisotropic behaviour. The vortex-stretching and viscous dissipation terms remain the leading order contributors to the vorticity and enstrophy transport for all cases when the flame is away from the wall, but as flame approach the wall, the baroclinic torque begins to play an increasingly important role. The combined molecular diffusion and dissipation contribution to the enstrophy transport remains negative away from the wall but it changes its sign near the wall due to the torque arising from dilatation rate gradient. Detailed physical explanations have been provided for the observed influences of flame and wall on the statistical behaviours of vorticity and enstrophy and the various terms of their transport equations. (C) 2016 Elsevier Masson SAS. All rights reserved.
机译：使用由等温惰性壁的湍流燃烧的近壁区域在近壁区域中的运输通过三维直接数值模拟（DNS）数据，其特征在于各种全球刘易斯数字LE（范围从0.8到1.2）和湍流强度。在所有情况下，涡流幅度都显示出其在壁上的最大值，并且涡流大小从燃烧到火焰刷的燃烧的气体侧下降显着下降。此外，涡流幅度显示出较小的LE减小和增加湍流强度的趋势。在火焰刷子内的涡流组分之间观察到大量各向异性，并且随着墙壁接近壁而增加的这种各向异性增加。已发现曲金扭矩术语主要是负责这种各向异性的行为。涡旋拉伸和粘性耗散条款仍然是所有情况的涡旋和敌对运输的领先订单贡献者，当火焰远离墙壁时，但随着火焰接近墙壁，曲尾扭矩开始发挥越来越重要的作用。对敌意运输的组合分子扩散和耗散贡献远离壁保持负面，但由于从扩张速率梯度产生的扭矩，它会改变其墙壁附近的标志。已经为Voltic和野兽统计行为以及其传送方程的各种方面的统计行为提供了详细的物理解释。 （c）2016 Elsevier Masson SAS。版权所有。

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