Novel Ultra-High Temperature Metal Seal with Single Crystal Spring Energizer

Resilient metallic structural seals are used to seal the secondary airflow regions in air and land based gas turbines. These seals are typically manufactured from thin strips of high temperature cold formable wrought superalloys, including alloy 718, Rene 41, and Waspaloy. Traditional wrought alloy seals exhibited excessive stress relaxation at temperatures above 730°C, which resulted in a loss of sealing integrity and excessive leakage. For applications above 730°C, seals are generally cooled using compressor bleed air which could otherwise be used to generate power. To minimize stress relaxation, an ultra-high temperature seal design incorporating a spring energizer made from cast single crystal turbine blade alloys was pursued. The creep-resistant cast single crystal blade alloy spring inserted in a wrought alloy sealing jacket provided the sealing force, increasing the service temperature of metallic seals to 950°C. This increase in seal performance is expected to reduce or eliminate the need to actively cool seals, improving the fuel efficiency of gas turbines.