Evaluation of brush seals for limited-life engines

Abstract

Brush seals are a relatively new concept for replacing labyrinth seals in gas turbine engines. An evaluation was performed to assess the potential of brush seals for limited-life gas turbine engines. A rotating rig was designed and built to test labyrinth and brush seals over a range of simulated engine conditions. An initial set of brush seals was rig-tested to determine leakage and wear performance and identify potential optimum configurations. The measured results showed that brush seals offer significant improvements over labyrinth seals with a factor of three or more reduction in leakage flow. Brush seals exhibit an initial wear-in period but retain significantly reduced leakage over labyrinth seals for times exceeding most limited-life engine applications. Consequently, brush seals offer the potential to precisely meter cooling/leakage air, thereby decreasing parasitic leakage and improving fuel consumption and thrust. Thus, brush seals are a definite candidate for replacing labyrinth seals in gas turbine engines.