Patent ID: 6234747
Filing Date: 2001-05-22
Classification: F01D,F04D,F05D,Y10S

Abstract:
A compressor stage comprising:a rotor disk;a plurality of circumferentially spaced apart blades extending radially outwardly from said disk, and each blade including circumferentially opposite pressure and suction sides extending radially from root to tip and axially between leading and trailing edges;an arcuate casing surrounding said blade tips and spaced radially outwardly therefrom to define a nominal tip gap therebetween;a plurality of circumferentially extending stall grooves disposed in an inner surface of said casing and facing said blade tips, and spaced axially apart by adjoining lands defining respective local gaps with said blade tips; andat least one of said lands is offset to locally increase a corresponding one of said local gaps larger than said nominal gap for reducing tip rubbing at said offset land as said tips rub said casing.