High-Temperature Braided Rope Seals for Static Sealing Applications

Achieving efe ciency and performance goals of advanced aircraft and industrial systems is leading designers to implement high-temperature materials 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 turbine sections, among others. Thermal strains that result in attaching the low expansion-rate components to high expansion-rate superalloy structures can cause signie cant life reduction in the components. Seals are being designed to both seal and serve as compliant mounts, allowing for relative thermal growths between high-temperature, but brittle, primary structures and the surrounding support structures. Designers require high-temperature, low-leakage, compliant seals to mitigate thermal stresses, and to control parasitic and cooling aire ow between structures. High-temperature braided rope seals are being developed in a variety of cone gurations to help solve these problems. This paper will describe the types of seals being developed, describe unique test techniques used to assess seal performance, and present leakage e ow data under representative pressure, temperature, and scrubbing conditions. Feasibility of the braided rope seals for both an industrial tube seal and a turbine vane seal application is also demonstrated.