Novel Concepts for Combustion Instability Reduction

A novel passive damping device concept to damp out low and high order combustion instability modes simultaneously in legacy, pipeline, and advanced military afterburners/combustors is proposed for development and demonstration in this SBIR project.The proposed novel passive damping device is based upon the concept of breaking up the tangential modes instability waves, generating vorticity shedding to increase damping, and obstructing the acoustic flow motion in the tangential direction at the locations where the most destructive instability occurs (i.e., screech) because the tangential pressure modes amplitudes reach their maximum at the chamber wall. The proposed hardware device concept is completely independent of any perforated liner and acts as an independent module that damps and leads to stabilization of the transverse pressure modes using a different physical mechanism than a liner.