A novel passive screech liner damping design concept to damp out low and high order screech modes simultaneously in legacy, pipeline, and advanced military afterburners are proposed for development and demonstration in this SBIR project. The proposed novel passive damping liner design concept is very retrofittable and implementable in any current or future augmentor systems without adding complexity and weight to the system or requiring supplemental cooling air. The proposed screech liner hardware concept will be designed, computationally analyzed, fabricated, and tested in Phase-I and Phase-I option of this SBIR project by leveraging an existing augmentor instability /screech liner damping rig designed, fabricated, and utilized to excite a low order tangential mode and then attempt to attenuate it using the new concept.
Benefit: Most of current gas turbine augmentors design databases and practices have been based upon testing of conventional screech liner designs with circular holes with various porosities for acoustic damping and the use of Helmholtz resonators with a single confined cavity. Current existing screech liners are designed in such a way as to attempt to suppress the most acoustic energy containing higher order transverse modes whether they are tangential or radial modes. The proposed damping liner design concept in this SBIR project is very unique in terms of allowing for more acoustic mass to be present and oscillate within the liner hole as compared to the conventional circular holes where the acoustic mass is restricted by the liner sheet thickness. Such new screech liner hardware and design concepts are currently unavailable commercially anywhere to the best of the project teams knowledge. Therefore, there is great interest and an immediate need for such a damping device for the gas turbine afterburners manufacturers. Such a screech liner will, therefore, be of great value for the afterburners manufactures.
Keywords: screech, screech, damping, Passive damping. Screech rig, Tangential Modes, Radial Modes, Perforated liner, Liner
