Mechanism of singeing flame excitation for a homogeneous mixture

The effect of vortex formation and the role of mixture flow rate in the excitation and sustenance of the self-oscillatory combustion regime of a kinetic singeing flame was studied experimentally. Using holographic interferometry and the Mies dispersion method, it is found that in the boundary layer at the burner exit, vortices arise periodically, which interact with the flame front to change the flame surface area and the heat release rate. It is shown that the main feedback mechanism is periodic vortex formation, and the occurrence of concentration regions of excitation and silence is related to the change in the number of waves falling on the flame height. It is found that in combustion of oxygen-rich fuel-air mixtures, acoustic oscillations arise at higher harmonics.