Integrity Testing of Brush Seal in Shroud Ring of T-700 Engine

Abstract

A split-ring brush seal was fabricated, installed between two labyrinth-honeycomb shroud seals, and tested in the fourth-stage turbine of a T-700 engine. The annealed Haynes 25 bristles rubbed directly against the nonconditioned, irregular Rene 80 turbine blade shroud surface. A total of 21 hr of cyclic and steady-state data were taken with surface speeds to 335 m/s (1100 ft/s) and shroud temperatures to 620°C (1150 °F). Wear appeared to be rapid initially, with an orange flash of hot brush fragments during the first engine startup, to minimal after 10 hr of operation. The brush survived the testing but experienced some bristle pullouts and severe bristle wear; some turbine interface wear and possible material transfer was noted.Future design concerns center on tribological behavior at the interface with or without lubricants.Post-test results indicated that perhaps two to three upstream bristle rows remained spread with possibly one downstream bristle row in

Wear of Brush Seals: Background and New Modeling Approach

“…In fact, it is possible to observe orange flash of hot brush fragments during the first engine startup (11). However, the tests conducted by Derby and England (3) show that, after being subjected to 15 million cycles of a 1.016 mm (0.040 inch) displacement at 650°C (1200°F), none of the bristles exhibit evidence of macroscopic deformation.…”

Brush Seal Performance and Durability Issues Basedon T‐700 Engine Test Results

“…Testing of a brush seal between two honeycomblabyrinth shroud seals (Figs. 2 and 3) in the fourth-stage turbine of a T-700 experimental engine revealed the following (Hendricks et al [1993b]):…”

Two‐ and Three‐Dimensional Numerical Experiments Representing Two Limiting Cases of an In‐Line Pair of Finger Seal Components

“…It is now universally recognized that this embodiment is much more effective than the labyrinth seal, and its deterioration is much delayed. There has been a considerable amount of experimental work that has advanced the state of the art of these types of seals (Atkinson and Bristol, 1992;Chupp and Dowler, 1991a;Ferguson, 1988;Forry, 1993;Hendricks et al, 1992;Proctor et al, 1996). During the same period, an effort was also afoot to validate numerical simulations through comparisons to the available experimental data.…”