Steady laminar flow structures with mixing, chemical reaction, and normal strain qualitatively representative of turbulent combustion at the small scales are analysed. A contrived counterflow configuration is examined to focus more easily on the premixed flames that are known to occur in multiple-flame structures; the premixed flame can be driven by a controlled heat source which is a surrogate for the diffusion flame in the practical multi-flame structure. Reduction to a one-dimensional similar form is obtained with density and properties variations. It is shown that premixed flames at fuel-rich or fuel-lean conditions sufficiently far from the stoichiometric condition are diffusion-controlled with a propagation velocity very weakly dependent on chemical kinetic details. In particular, heat diffused from a downstream source (i.e. the surrogate for a diffusion flame) is needed to sustain the flame. Effects of normal-strain rate, pressure level, and transport properties, combustible mixture composition, and heat source strength are determined through a parameter study with variations in Damköhler number, Prandtl number, upstream mass fractions of oxygen and propane fuel, and wall temperature. The premixed flame becomes less dependent on the downstream source as strain rate decreases and pressure increases. Small changes in heat and mass diffusivities have stronger effects than an order-of-magnitude change in Damköhler number.

分析了具有混合、化学反应和法向应变的稳态层流结构，这些结构在小尺度上定性地代表了湍流燃烧。检查了人为的逆流配置，以更容易地关注已知发生在多火焰结构中的预混火焰；预混火焰可由受控热源驱动，该热源可替代实际多火焰结构中的扩散火焰。随着密度和特性的变化，可以减少到一维相似的形式。结果表明，在离化学计量条件足够远的富燃料或贫燃料条件下，预混火焰是由扩散控制的，其传播速度非常弱地取决于化学动力学细节。特别是，热量从下游源（即 需要扩散火焰的替代品）来维持火焰。法向应变率、压力水平和传输特性、可燃混合物成分和热源强度的影响通过参数研究确定，其中 Damköhler 数、Prandtl 数、氧气和丙烷燃料的上游质量分数以及壁温的变化。随着应变率降低和压力增加，预混火焰对下游源的依赖性降低。热量和质量扩散率的微小变化比 Damköhler 数的数量级变化具有更强的影响。热源强度和热源强度是通过参数研究确定的，包括 Damköhler 数、Prandtl 数、上游氧气和丙烷燃料的质量分数以及壁温。随着应变率降低和压力增加，预混火焰对下游源的依赖性降低。热量和质量扩散率的微小变化比 Damköhler 数的数量级变化具有更强的影响。热源强度和热源强度是通过参数研究确定的，包括 Damköhler 数、Prandtl 数、上游氧气和丙烷燃料的质量分数以及壁温。随着应变率降低和压力增加，预混火焰对下游源的依赖性降低。热量和质量扩散率的微小变化比 Damköhler 数的数量级变化具有更强的影响。