Study on Suppression of Combustion Instability using Quarter Wavelength Tube

The passive suppression of combustion instability by quarter wavelength tube was hereby studied to absorb the oscillation pressure with large amplitudes caused by combustion instability. The suppression effects of quarter wavelength tube on combustion instability were systematically analyzed by combining the acoustic numerical simulation and the experimental research methods. Firstly, the influence of quarter wavelength tube on the acoustic characteristics of the system was analyzed using acoustic numerical simulation; and then, the acoustic absorption characteristics to external acoustic disturbance and the suppression effects on the self-excited combustion instability were experimentally studied. The results show that the quarter wavelength tube can effectively absorb the acoustic pressure when the dominant frequency of acoustic pressure is close to the resonance frequency of the system, and can effectively suppress the combustion instability under acoustic resonance. However, given that the quarter wavelength tube adds adjoint dominant frequencies after eliminating the original resonant frequency of the system, and the combustion instability is stabilized on the adjoint dominant frequencies, combustion instability suppression is different from noise suppression. In addition, the diameter of wavelength tube exercises obvious effects on the above characteristics. All these make it necessary to determine the best parameters and the maximum suppression efficiency by combining numerical simulation and experiments. The research results of this paper provide theoretical and technical supports for the suppression of combustion instability by the quarter wavelength tube.