The Tri-services JTAGG II engine uses two identical brush seals, in tandem, located aft of the high pressure compressor. The engine operating conditions, at intermediate rated power (IRP), for this seal are estimated to be 50 000 rpm (899 ft/sec) speed, 175 psid air to air pressure differential and 1200°F air temperature. The testing was comprised of static air leakage, performance, seal offset, rotor run out tests and a 50 hr endurance test in the NASA Lewis seal rig. Based on the test

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... it is concluded that the brush seal design should be able to meet the air leakage flow factor goal of less than 0.004 for the engine IRP operating conditions. As a comparison, a labyrinth seal in this location with a 0.005 in. typical radial clearance has an estimated leakage flow factor of 0.007. The long term seal life can not be predicted accurately due to the limited endurance testing of 50 hr. However, based on the excellent condition of the test seal and rotor after 50 hr of testing, it is anticipated that the seals should easily meet the JTAGG II engine test requirement. • The seal pair (S/N 1 and 2) tested, showed considerable hysteresis as is evident in Fig. 11. This test J | Air 17. SECURITY CLASSIFICATION OF REPORT Unclassified NSN 7540-01-280-5500 18. SECURITY CLASSIFICATION OF THIS PAGE Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT Unclassified 15. NUMBER OF PAGES 17 16. PRICE CODE A03 20. LIMITATION OF ABSTRACT Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. Z39-18 298-102