Hydrodynamic theory of premixed flames: effects of stoichiometry, variable transport coefficients and arbitrary reaction orders
Hydrodynamic theory of premixed flames: effects of stoichiometry, variable transport coefficients and arbitrary reaction orders
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DOI：
10.1017/s0022112003004683
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发表时间：
2003-06
影响因子：
3.7
通讯作者：
M. Matalon;C. Cui;J. Bechtold
中科院分区：
文献类型：
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作者：
M. Matalon;C. Cui;J. Bechtold
基于流体动力学长度，这是典型的大于标称火焰厚度，预混火焰可以被看作是一个表面的密度不连续，平流和扭曲的流动。的速度和压力遭受突然的变化，在整个火焰前，包括朗肯-Hugoniot跳跃条件，以领先的顺序，与校正的顺序的火焰厚度，占横向通量和积累。为了完成配方，火焰温度和传播速度，其中变化沿着火焰的流场和火焰前曲率的局部不均匀性的结果，表达式推导。与以往的研究，假设一个单一的不足反应物组成的混合物，本研究使用了两个反应物的计划，因此认为混合物的组成从贫到富的条件。此外，非统一和一般的反应顺序被认为是在试图模仿更广泛的反应机制，并更好地代表实际的实验条件下，所有的传输系数被允许任意依赖于温度。本模型，在一个坐标自由的形式表示，是有效的任意形状的火焰在一般的流体流动中传播，无论是层流或湍流。
Based on a hydrodynamic length, which is typically larger than the nominal flame thickness, a premixed flame can be viewed as a surface of density discontinuity, advected and distorted by the flow. The velocities and the pressure suffer abrupt changes across the flame front that consist of Rankine–Hugoniot jump conditions, to leading order, with corrections of the order of the flame thickness that account for transverse fluxes and accumulation. To complete the formulation, expressions for the flame temperature and propagation speed, which vary along the flame as a result of local non-uniformities in the flow field and of flame front curvature, are derived. Unlike previous studies that assumed a mixture consisting of a single deficient reactant, the present study uses a two-reactant scheme and thus considers mixtures whose compositions vary from lean to rich conditions. Furthermore, non-unity and general reaction orders are considered in an attempt to mimic a wider range of reaction mechanisms and, to better represent actual experimental conditions, all transport coefficients are allowed to depend arbitrarily on temperature. The present model, expressed in a coordinate-free form, is valid for flames of arbitrary shape propagating in general fluid flows, either laminar or turbulent.