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Fluidic oscillators are of special interest for fuel-based active control schemes featuring high frequency fuel flow modulation, as they are much more durable then conventional valves due to the absence of fast moving parts. In this work the performance of a fluidic oscillator in an active combustion control scheme is demonstrated. The oscillation frequency was controlled by varying the inlet mass flow of the oscillator. High speed camera recordings and hot wire measurements were performed to investigate the fluidics' oscillation characteristics. The oscillator was then incorporated into a bluff body burner, where it modulated parts of the fuel flow blended with nitrogen. Pressure and heat release fluctuations in the combustor were recorded and images of the flame were taken. At stable combustion the spectra of the heat release signals showed a clear peak corresponding to the fluidics' oscillation frequency, thus validating the ability of the oscillator to influence the combustion process. When operating the combustor at conditions that featured a strong low-frequency combustion instability, applying fuel modulation resulted in attenuation of the combustion instability for some oscillation frequencies. The attenuation was highest when modulating the fuel flow in between the fundamental instability frequency and its subharmonic. The results obtained in this work show that the fluidic oscillator in use allows for fuel modulation and hence combustion control without the need for complex and fast moving parts, thus ensuring a long actuator lifetime. This makes the fluidic oscillator highly appropriate for application in industrial gas turbines.

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