M-shaped flame dynamics

Abstract

This article deals with the dynamics of a cylindrical bluff-body-stabilized M-shaped premixed flame at low flow rates. A comparative analysis with classical conical flames was performed. The velocities and flame front field dynamics were studied with the use of numerical methods. It was shown that the processes under the investigation are similar to those in a conical flame. The flame front is deformed by moving Kelvin-Helmholtz vortices along the front. It was found that M-shaped flame tips perform in-phase low-frequency oscillations in both vertical and horizontal directions as opposed to the conical one. It was also found that fuel enrichment does not affect the frequency of the flicker as compared to the classical conical flame. A number of experiments have shown that vertical displacement amplitude in M-shaped flame is approximately 3.5 times smaller than in a conical one at the same flow rate. An explanation of this phenomenon is the fact that a part of the energy under compression goes to the horizontal displacement of the front.