Effect of Shrouded Stator Leakage Flows on Core Compressor Studied

Investigation of leakage effects on the aerodynamic performance of shrouded compressor stators. Left: Meridional view of NASA's low-speed axial-flow compressor. Right: Pressure loss coefficient as function of percent span from hub.

The Low-Speed Compressor features shrouded stator seal cavities with a single labyrinth seal tooth. Measurements of the power stream aerodynamics have been made for a range of seal tooth clearances. In the initial series of tests, the seal tooth clearances were changed in all four stages. In a second series of tests, the seal clearance was changed in only the third stage. Results from both test series indicate that significant changes in the power stream aerodynamics occur with different seal leakage rates. For example, the change in total pressure loss across the third stator is shown in the figure for a range of seal tooth clearances. The measured results indicate that the power stream aerodynamics are influenced across the lower 40 percent of the blade span by the leakage flow. The measured results will be compared with computational fluid dynamics simulations in which the seal cavity is included in the computational domain. The results will also be used to develop a simple leakage flow model for future computational fluid dynamics simulations so that the actual seal cavity will not have to be included in the computational domain.