Flow turbulence and intrinsic flamefront cellular instability can each wrinkle a flamefront and thereby increase its surface area and the corresponding global flame speed, with the characteristics of wrinkling depending on the separate and coupled spectra of their respective length scales. Extending our previous study on the interaction between turbulence and the hydrodynamic, Darrieus–Landau cellular instability, and using the same expanding, globally spherical flame as the vehicle of investigation, we report herein experimental results on the interaction between turbulence and diffusional-thermal cellular instability relevant for mixtures with sub-unity Lewis numbers. Results show that the flame acceleration is primarily controlled by cellular instability in the wrinkled flamelet regime and by turbulence in the thickened flamelet regime, respectively, while both mechanisms influence the propagation in the corrugated flamelet regime. It is also noted that while the Lewis number and thus diffusional-thermal instability does not affect the global flame acceleration, it does enhance the total burning rate.

湍流和固有的火焰前锋细胞不稳定性会各自使火焰前锋起皱，从而增加其表面积和相应的整体火焰速度，而起皱的特性则取决于它们各自长度尺度的分离和耦合光谱。扩展了我们先前对湍流与流体动力学，Darrieus-Landau细胞不稳定性之间相互作用的研究，并使用相同的膨胀全球球形火焰作为研究工具，我们在此报告了湍流与扩散热细胞不稳定性之间相互作用的实验结果与具有亚单位路易斯数的混合物有关。结果表明，火焰加速主要受皱纹小火焰状态下的细胞不稳定性和增厚小火焰状态下的湍流的控制，虽然这两种机制都会影响波纹形火焰小波区域的传播。还应注意的是，尽管路易斯数和因此的扩散热不稳定性不影响整体火焰加速，但它确实提高了总燃烧速率。