Aeropropulsion and Power Technology

We propose the development of passive radiators to be used for adding low-frequency (<1000 Hz) acoustic damping, to mitigate combustion instability in augmentors. These radiators can be viewed as tuned absorbers and will be tuned to the resonant frequency(ies) of the sympathetic mode(s). Once tuned, they will provide an effective fluid loading at their tuned frequency, i.e., the resonant frequency of a sympathetic mode. The number and locations of these radiators are design variables and will be determined so that the radiators couple well with the target mode(s) of the augmentor and thus absorb its(their) energy. We also propose to develop a software tool that assists the designers in the synthesis and analysis of stability mitigation solutions for augmentors. This design tool will be developed in Matlab/Simlink environment and will be based on two sub-systems of acoustics and combustion dynamics feeding back into each other. The modal data used in constructing the acoustic dynamics of the combustion system will be generated in ANSYS finite element analysis environment and then exported to Matlab.