斜壁限制域台阶对火焰宏观结构的影响

Slope-wall confinement is an effective passive control method for combustion oscillation. To deeply understand its flame stabilization characteristics, the influence of step height in the slope-wall confinement on the flame macrostructure was explored. Numerical simulation showed that increasing the height of the step changed the flame macrostructure from V-shaped to M-shaped structure. By quantitatively calculating the flame stretch rate, it was found that this transition was accompanied by the occurrence of an area with a significantly strong stretch flow on the outside of the slope-wall transition section. Combined with the small disturbance linear stability theory, the reason for this phenomenon can be summarized as the structural feature-length scale was larger than the spatial unstable mode 1/4 wavelength length scale. Thus, the inherently unstable mode was excited, and a region with a strong stretch rate for flame stabilization was formed. This method was used to predict the height of the critical step, through which the absolute error did not exceed 0.1 mm.