HIGH-TEMPERATURE BRAIDED ROPE SEALS FOR STATIC SEALING APPLICATIONS

Achieving efficiency and performance goals of advanced aircraft and in dustrial systems is leading designers to implement high-temperature ma terials such as ceramics and intermetallics. Generally, these advanced materials are applied selectively in the highest temperature sections of the engine system, including the combustor and high-pressure turbi ne sections, among others, Thermal strains that result in attaching th e low expansion-rate components to high expansion-rate superalloy stru ctures can cause significant life reduction in the components, Seals a re being designed to both seal and serve as compliant mounts, allowing for relative thermal growths between high-temperature, but brittle, p rimary structures and the surrounding support structures. Designers re quire high-temperature, low-leakage, compliant seals to mitigate therm al stresses, and to control parasitic and cooling airflow between stru ctures. High-temperature braided rope seals are being developed in it variety of configurations to help solve these problems. This paper wil l describe the types of seals being developed, describe unique test te chniques used to assess seal performance, and present leakage dow data under representative pressure, temperature, and scrubbing conditions, Feasibility of the braided rope seals for both an industrial tube sea l and a turbine vane seal application is also demonstrated.