Effects of Soret diffusion on laminar flames

Abstract

Mass diffusion plays a critical role in laminar flames. It affects and even controls flame propagation, ignition and extinction. Usually Ficikan diffusion driven by concentration gradient is dominant while Soret diffusion driven by temperature gradient is relatively small. Therefore, in theoretical analysis and numerical simulation, only Fickian diffusion is considered and Soret diffusion is neglected. However, previous studies indicated that Soret diffusion cannot be neglected for cases with sufficiently light or heavy species and strong temperature gradients. This paper reviews the effects of Soret diffusion on laminar flames. Specifically, we discuss the influence of Soret diffusion on (1) flame propagation, ignition and extinction of premixed planar flames and stretched flames, (2) flame structure and extinction of non-premixed flames, and (3) spray combustion and soot formation.