Wind-aided flame spread under oblique forced flow
Wind-aided flame spread under oblique forced flow
复制标题
斜向强制流下风助火焰蔓延
DOI：
10.1016/s0010-2180(99)00038-3
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发表时间：
1999
影响因子：
4.4
通讯作者：
A. Liñán
中科院分区：
文献类型：
--
作者：
J. Tizón;J. Salvá;A. Liñán
分析了无重力和重力诱导流占主导地位时，固体燃料棒在斜向强迫流作用下的风助火焰沿着传播过程。横向速度足够大，以确保燃料蒸汽和空气的混合发生在燃料棒周围的薄边界层中，我们可以使用边界层近似来描述气相化学反应和顺风火焰传播过程。一个全球性的，二阶，阿克里乌斯表达式被用来描述气相反应，而固体表面气化反应是在一个恒定的热解温度建模。固体被从火焰中对流出来的热气体加热，热气体的对流是通过速度在火焰传播方向上的轴向分量进行的。假设固体中加热层的厚度与棒半径相比很小，则固体将被视为热厚。分析确定了火焰传播速度和火焰前沿区域的流动结构。分析还表明，火焰传播是不可能的，在大流速由于有限速率的影响，而在低速度的气相反应是扩散控制。通过包括从表面的辐射损失的火焰传播极限，在低速下，也发现在本分析。
The wind-aided flame spread process along a solid fuel rod under oblique forced flow is analyzed in absence of gravity or when the forced flow dominates the gravity-induced flow. The transverse velocity is large enough to ensure that mixing of the fuel vapors and air occurs in a thin boundary layer surrounding the fuel rod and we can use the boundary layer approximation to describe the gas-phase chemical reaction and downwind flame spread process. A global, second-order, Arrhenius expression is employed to describe the gas-phase reaction, while the solid surface gasification reaction is modeled in terms of a constant pyrolysis temperature. The solid is heated by the hot gases convected from the flame by the axial component of the velocity in the direction of the flame spread. The solid will be considered thermally thick, assuming the thickness of the heated layer in the solid to be small compared with the rod radius. The analysis determines the flame spread velocity and the flow structure in the flame front region. The analysis also shows that flame spread is not possible at large flow velocities due to finite rate effects, while at low velocities the gas-phase reaction is diffusion-controlled. By including radiation losses from the surface a flame spread limit, at low velocities, is also found in the present analysis.