关键词: 非预混火焰;格林函数法;热斑的产生和演化;理论计算 

Abstract: In non-premixed flames, the combustion zone is controlled by the mixing process between fuel and oxidizer. The chemical reaction occurs in a finite space and shows obviously distributed characteristics. The flame surface (or stoichiometric contour) may be split due to flow perturbations. Under these circumstances, the generation and evolution of hot spots become a key problem in stability analysis of non-premixed flames.Based on the Burke-Schumann assumptions, the generation and evolution of hot spots were analytically calculated for an idealized, two-dimensional, flat, non-premixed flame by Green’s function method. The results show that a smaller Strouhal number, a larger Peclet number or a faster convective velocity causes the hot spots to move farther downstream. These results are valuable for a better understanding of the mechanisms of non-premixed combustion instability, which is beneficial to the development of accurate control techniques.

Key words: Non-premixed flame; Green’s function method; Generation and evolution of hot spots; Analytical calculation