论文标题
关于在封闭和半开管中形成郁金香火焰
On the formation of a tulip flame in closed and semi-open tubes
论文作者
论文摘要
本文研究了郁金香火焰形成的机理，以在各种纵横比和半开管中闭合试管中传播的火焰。使用高分辨率的直接数值模拟，对2D通道中的郁金香火焰的形成，对反应性Navier Stokes方程以及用于化学计量氢/空气火焰的详细化学模型的直接数值模拟。结果表明，在减速阶段，火焰产生的稀疏波在郁金香形的火焰形成中起着关键作用。稀疏波与先前产生的反向流的相互作用在未燃烧的气体中加速了火焰流，从而导致火焰前近场区和边界层厚度增加的近场区域的流速下降。轴向速度在火焰前面接近的曲线采用倒郁金香的形式。因此，火焰前部获得了郁金香形状，在很大程度上重复了上游流动中轴向速度曲线的形状。
The paper examines the mechanism of the tulip flame formation for the flames propagating in closed tubes of various aspect ratios and in a half-open tube. The formation of tulip flames in 2D channels is studied using high resolution direct numerical simulations of the reactive Navier Stokes equations coupled with a detailed chemical model for a stoichiometric hydrogen/air flame. It is shown that rarefaction waves generated by the flame during the deceleration stage play a key role in the tulip-shaped flame formation. The interaction of the reverse flow created behind the rarefaction wave with previously produced be accelerating flame flow in the unburned gas, results in the decrease of the flow velocity in the near field zone ahead of the flame and in the increase of the boundary layer thickness. The profile of the axial velocity close ahead of the flame takes the form of an inverted tulip. Therefore, the flame front acquires a tulip shape repeating to a large extent the shape of the of the axial velocity profile in the upstream flow.
