Scavenge methodologies for turbine engine particle separation concepts

Abstract

A method for scavenging small particles from a turbine engine includes directing compressed air through a flowpath, downstream of a compressor, which causes a reduction in a radial flow component and the introduction of or an increase in an axial flow component of the compressed air, removing a portion of the compressed air from the flowpath and directing the portion into a scavenge plenum, the scavenge plenum being positioned adjacent to and radially outward from the flow path, and returning the portion of the compressed air from the plenum to the flowpath while maintaining a majority of the small particles that were present in the portion within the scavenge plenum. Further, the method includes removing the majority of small particles from the plenum. The step of removing occurs intermittently during engine operation, during engine shutdown, or while the engine is not operation, but does not occur continuously during engine operation.

What is claimed is: 
     
         1 . A method for scavenging small particles from a turbine engine, the method comprising the steps of:
 compressing air in a compressor that rotates about a longitudinal axis to generate compressed air, wherein the compressed air that exits the compressor includes at least a tangential flow component and a radial flow component, and wherein the compressed air comprises a plurality of small particles;   directing the compressed air through a flowpath, downstream of the compressor, which causes a reduction in the radial flow component and the introduction of or an increase in an axial flow component;   removing a portion of the compressed air from the flowpath and directing the portion into a scavenge plenum, the scavenge plenum being positioned adjacent to and radially outward from the flow path;   returning the portion of the compressed air from the plenum to the flowpath while maintaining a majority of the small particles that were present in the portion within the scavenge plenum; and   removing the majority of the small particles from the plenum using a scavenging methodology, wherein the step of removing occurring intermittently during engine operation, during engine shutdown, or while the engine is not operation, but does not occur continuously during engine operation.   
     
     
         2 . The method of  claim 1 , wherein the compressor is a centrifugal compressor or a mixed-flow compressor. 
     
     
         3 . The method of  claim 1 , wherein the flowpath comprises an arc located between a diffuser assembly of the turbine engine and a deswirl assembly of the turbine engine, both assemblies being located downstream of the compressor but upstream of a combustor of the turbine engine. 
     
     
         4 . The method of  claim 1 , wherein the scavenging methodology comprises withdrawing small particles from a port of the plenum. 
     
     
         5 . The method of  claim 4 , wherein the port is configured at an axial angle, a radial angle, a tangential angle, or a compound/combination angle thereof. 
     
     
         6 . The method of  claim 5 , wherein the port is coupled with a purge valve. 
     
     
         7 . The method of  claim 1 , wherein the scavenging methodology comprises withdrawing small particles through an outlet of the plenum, the plenum being configured in a scroll configuration. 
     
     
         8 . The method of  claim 7 , wherein the outlet is couple with a purge valve. 
     
     
         9 . The method of  claim 1 , wherein the scavenging methodology comprises collecting small particles in a filter of the plenum and removing and cleaning the filter while the turbine engine is not operating. 
     
     
         10 . The method of  claim 1 , wherein the scavenging methodology comprises directing small particles into a bypass circuit coupled with the plenum, the bypass circuit comprising a filter, and removing and cleaning the filter while the turbine engine is not operating. 
     
     
         11 . The method of  claim 1 , wherein directing the portion into a scavenge plenum comprises directing the portion through an extraction slot at an outer wall of the flowpath and located radially inward and downstream from a radial apex of the outer wall of the flowpath. 
     
     
         12 . The method of  claim 11 , wherein the extraction slot comprises a continuous circumferential slot, a discontinuous circumferential slot, or as a series of circumferentially-disposed holes/apertures of any shape or count. 
     
     
         13 . The method of  claim 1 , wherein directing the portion into a scavenge plenum comprises direction the portion through a plurality of holes or openings at an outer wall of the flowpath and located substantially at a radial apex of the outer wall of the flowpath. 
     
     
         14 . The method of  claim 13 , wherein the plurality of holes or openings are angled circumferentially at about 25 to about 65 degrees and axially at about 5 to about 20 degrees, said angling being with respect to a solely-radially oriented hole or opening. 
     
     
         15 . The method of  claim 13 , wherein directing the portion into a scavenge plenum further comprises directing the portion through an extraction slot at the outer wall of the flowpath and located radially inward and downstream from a radial apex of the outer wall of the flowpath. 
     
     
         16 . The method of  claim 1 , wherein the small particles are less than or equal to about 20 microns in greatest cross-sectional length. 
     
     
         17 . The method of  claim 1 , wherein the turbine engine comprises two compressors, and wherein the method is performed on air flow exiting each of the two compressors. 
     
     
         18 . The method of  claim 1 , wherein the turbine engine is embodied as a propulsion-type turbine engine or as an auxiliary power unit (APU). 
     
     
         19 . The method of  claim 1 , wherein the turbine engine is implemented on an aircraft, a land vehicle, or a watercraft.