COMBUSTION INSTABILITY RELATED TO VORTEX SHEDDING IN DUMP COMBUSTORS AND THEIR PASSIVE CONTROL

This review summarizes recent research program related to the driving mechanism of dump combustor instability. Its scope includes experimental research in dump combustors using gaseous fuel. The emphasis here is on vortex shedding as a driving mechanism of combustion instabilities. It is shown that the development of coherent flow structures and their breakdown into fine-scale turbulence can lead to periodic heat release, which, when in phase with the pressure oscillation, can drive the oscillations as stated by the Rayleigh criterion. The physical processes associated with the vortex breakdown are described. This understanding is used to passively control and reduce the pressure oscillations, as demonstrated for dump and bluff body stabilized combustion flows.