ACOUSTIC MODES ATTENUATION ON ROCKET ENGINES USING HELMHOLTZ RESONATORS: EXPERIMENTAL VALIDATION

This work describes a methodology to experimentally validate a Helmholtz resonator design applied to attenuate acoustic oscillations inside a combustion chamber of a rocket engine. Using the Finite Element Method (FEM), an acoustic cavity virtual prototype was built. In order to experimentally validate this model, the acoustic characterization of the rocket engine cavity was done with and without a tuned Helmholtz resonator, in a cold test procedure. The results have presented very good agreement between numerical and experimental models of the chamber. After the design and installation of the resonators, the experimental results showed an attenuation of approximately 10 dB in a determined tuned frequency that coincides with an acoustic mode of the cavity.