Filament-Wound Tip-Shrouded Axial Compressor or Fan Rotor System

Abstract

A filament-wound tip-shrouded axial compressor or fan rotor system is described that employs a brush seal to minimize the leakage of flow that has passed through the rotor from re-entering the rotor inlet region. A circumferential array of small orifices through the outer casing just behind the brush seal is further provided to allow a small flow of air between the rotating shroud and the casing in order to limit the temperature rise due to aerodynamic heating of the fluid immediately adjacent to the filament winding.

I claim: 
     
         1 . A turbomachine for compressing air comprising:
 a stationary casing disposed about a longitudinal axis,   a rotor assembly mounted for rotation about the longitudinal axis, the rotor assembly having a plurality of blades, tips of the blades being coupled to an annular shroud, the annular shroud containing an axially-narrow external cylindrical metallic surface at its leading edge, the remainder of the shroud being wound with carbon filaments embedded in a polymer matrix and disposed with respect to the stationary casing so as to define a gap extending continuously between an outer surface of the annular shroud and an inner surface of the stationary casing,   and a seal structure attached to the stationary casing, comprised of a plurality of metallic fibers or brushes in light contact with said axially-narrow external cylindrical metallic surface at the leading edge of the rotor shroud, said fibers inclined at an approximately 45 degree angle leaning in the direction of rotor rotation   
     
     
         2 . The turbomachine of  claim 1  wherein a circumferentially-distributed array of orifices passing through the stationary casing is located aft of but close to said seal structure. 
     
     
         3 . The turbomachine of  claims 1  and  2  wherein a manifold is provided, collecting air emerging from said circumferentially-distributed array of orifices, said manifold ducting said air to any other location within the engine. 
     
     
         4 . The turbomachine of  claims 1 ,  2  and  3  wherein the manifold of  claim 3  ducts said air to a control valve modulating the quantity of flow of said air as a function of engine operating point.