Active Combustion Control Using a Fluidic Oscillator for Asymmetric Fuel Flow Modulation

Abstract

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 ...