Preferential-Diffusion/Stretch Interactions in Laminar Premixed Flames

PI最近证明，在实际应用中，拉伸和优先扩散可以对层流燃烧速度产生显著影响，从而对湍流火焰速度产生影响。这一建议是这项工作的延伸，将包括在低重力条件下层流燃烧速度的一些测量，以尽量减少浮力的影响。PI建议使用向外传播的球形层流火焰技术和短滴塔（测试时间~ 500 ms）来进行这些测量。具体目标将包括：(1)使用各种燃料、氧化剂/稀释剂混合物和压力，对未拉伸层流燃烧速度和优先扩散/拉伸相互作用（或马克斯坦数）进行新的测量。(2)未拉伸和拉伸预混火焰的数值模拟，包括化学动力学和多组分扩散的详细模型。(3)利用这些结果来评估理论预测，并帮助诊断优先扩散/拉伸相互作用的机制，并估计负拉伸条件下的火焰行为。

The PI has recently demonstrated that stretch and preferential diffusion can have a significant effect on laminar burning velocities and consequently on turbulent flame speeds in practical applications. This proposal is an extension of this work and will include some measurements of laminar burning velocities under low-gravity conditions in order to minimize the effects of buoyancy. The PI proposes to use an outwardly-propagating spherical laminar flame technique and a short drop tower (test time ~ 500 ms) to carry out these measurements. Specific objectives will include: (1) New measurements of unstretched laminar burning velocities and preferential-diffusion/stretch interactions (or Markstein numbers), using various fuels, oxidant/diluent mixtures and pressures. (2) Numerical simulation of both unstretched and stretched premixed flames including detailed models of chemical kinetics and multicomponent diffusion. (3) Use of these results to evaluate theoretical predictions, and to help diagnose the mechanism of preferential-diffusion/stretch interactions and estimate flame behavior under negative stretch conditions.