Use of exhaust gas recirculation as a control approach for thermoacoustic instabilities

Investigation into exhaust gas recirculation (EGR) as a method for reducing costs of postcombustion carbon capture in gas turbine systems reveals that EGR offers potential applications as a control strategy for thermoacoustic instabilities. Introduction of EGR allows semi-independent variation of the operating parameter of flame temperature and characteristic flame length scales, known to play a primary role in the phase of the thermoacoustic coupling mechanism. Measurements were made showing the ability of EGR to reduce the amplitude of thermoacoustic oscillations over a range of operating conditions in a laboratory scale, swirled dump combustor, without affecting the flame temperature. Theoretical analysis was also performed to investigate the limitations on the ability of this approach to influence dynamics.