Cylindrical air guide in a turbine engine

Abstract

An air/oil separator for a gas turbine engine includes a drive shaft having a central axis extending in an axial direction, a free vortex chamber mounted radially around the drive shaft, a separation chamber coupled with the free vortex chamber in the axial direction opposite to the drive shaft, and a rotatable outlet shaft radially rotatable and having an inlet end coupled with the separation chamber opposite to the free vortex chamber, an outlet end, and a hollow interior chamber therebetween. The hollow interior chamber has an inner circumference extending in the axial direction a cylindrical air guide extending coaxially therein. The cylindrical air guide has a nonporous cylindrical main body, an upstream end fixedly coupled with the inlet end of the rotatable outlet shaft, and a downstream end coaxially disposed within the outlet end of the rotatable outlet shaft.

What is claimed is: 
     
       1. An air/oil separator for a gas turbine engine, said air/oil separator comprising:
 a drive shaft having a central axis extending in an axial direction; 
 a free vortex chamber mounted radially around said drive shaft; 
 a separation chamber coupled with said free vortex chamber in the axial direction on a side of said free vortex chamber opposite to said drive shaft; 
 a rotatable outlet shaft having an inlet end, an outlet end, and a hollow interior chamber therebetween, said hollow interior chamber having an inner circumference extending in the axial direction, said inlet end coupled with said separation chamber on a side of said separation chamber opposite to said free vortex chamber, and said rotatable outlet shaft radially rotatable about the central axis; and 
 a cylindrical air guide comprising; 
 a nonporous cylindrical main body having a smooth, uninterrupted outer surface and an outer circumference extending coaxially within the inner circumference of said hollow interior chamber of said rotatable outlet shaft, said inner circumference having a diameter greater than a diameter of the cylindrical air guide; 
 an upstream end fixedly coupled with said inlet end of said rotatable outlet shaft; and 
 a downstream end coaxially disposed within said outlet end of said rotatable outlet shaft. 
 
     
     
       2. The air/oil separator of  claim 1 , wherein said rotatable outlet shaft further comprises a plurality of air discharge slots disposed radially about said hollow interior chamber at said inlet end. 
     
     
       3. The air/oil separator of  claim 2 , wherein said plurality of air discharge slots are configured to allow air communication between said separation chamber and said hollow interior chamber of said rotatable outlet shaft. 
     
     
       4. The air/oil separator of  claim 3 , further comprising an upstream mount, wherein said upstream end of said cylindrical air guide is fixedly coupled with said inlet end of said rotatable outlet shaft by said upstream mount, and wherein said upstream mount is mounted upstream of said plurality of air discharge slots. 
     
     
       5. The air/oil separator of  claim 4 , wherein said upstream mount is configured to prevent air flowing upstream of said plurality of air discharge slots within said hollow interior chamber. 
     
     
       6. The air/oil separator of  claim 4 , wherein said upstream mount is disc-shaped. 
     
     
       7. The air/oil separator of  claim 4 , wherein said upstream mount is ring-shaped. 
     
     
       8. The air/oil separator of  claim 7 , wherein said ring-shaped upstream mount has an inner circumference and an outer circumference, said inner circumference of said ring-shaped upstream mount configured to seal said ring-shaped upstream mount to said outer circumference of said upstream end of said cylindrical air guide, and said outer circumference of said ring-shaped upstream mount configured to seal said ring-shaped upstream mount to said inner circumference of said hollow interior chamber of said rotatable outlet shaft. 
     
     
       9. The air/oil separator of  claim 3 , wherein said drive shaft further comprises a hollow interior shaft opening located upstream of said plurality of air discharge slots, said hollow interior shaft opening having an inner dimension configured to allow an interference fit with said upstream end of said cylindrical air guide. 
     
     
       10. The air/oil separator of  claim 9 , wherein the interference fit of said upstream end of said cylindrical air guide with said hollow interior shaft opening of said drive shaft is configured to prevent air flowing upstream of said plurality of air discharge slots within said hollow interior chamber. 
     
     
       11. The air/oil separator of  claim 10 , further comprising at least one mounting connector fixedly attaching said upstream end of said cylindrical air guide to said driveshaft upstream of said plurality of air discharge slots. 
     
     
       12. The air/oil separator of  claim 1 , wherein said downstream end of said cylindrical air guide is fixedly coupled with said outlet end of said rotatable outlet shaft by at least one mounting connector. 
     
     
       13. The air/oil separator of  claim 12 , wherein said at least one mounting connector is configured to permit airflow from exiting said hollow interior chamber of said rotatable outlet shaft at said outlet end. 
     
     
       14. The air/oil separator of  claim 1 , wherein said downstream end of said cylindrical air guide is coaxially coupled with said outlet end of said rotatable outlet shaft by cantilevered support of said upstream end fixedly coupled with said inlet end of said rotatable outlet shaft. 
     
     
       15. The air/oil separator of  claim 1 , wherein said nonporous cylindrical main body comprises a cylindrical outer wall, and wherein said nonporous cylindrical main body is hollow inside of said cylindrical outer wall. 
     
     
       16. The air/oil separator of  claim 1 , wherein said hollow interior chamber of said rotatable shaft comprises a plurality of interior sections having a progressively smaller interior diameter approaching the outlet end of said rotatable outlet shaft. 
     
     
       17. A method for discharging exhaust air from air/oil separator of a gas turbine engine, the air/oil separator having a separation chamber and a hollow rotatable outlet shaft, said method comprising:
 venting exhaust air from the separation chamber into a first end of the hollow rotatable outlet shaft through air discharge slots in a direction substantially perpendicular to a longitudinal central axis of the hollow rotatable outlet shaft, the air discharge slots providing air communication between the separation chamber and the rotatable outlet shaft; 
 rotating the rotatable outlet shaft around the longitudinal central axis; and 
 guiding airflow of the exhaust air through the hollow rotatable outlet shaft, from the first end to a second opposing end thereof, radially around a cylindrical air guide having a smooth, uninterruptable outer surface and coaxially mounted within the rotating outlet shaft about the longitudinal central axis, while preventing airflow from reaching the central longitudinal axis. 
 
     
     
       18. The method of  claim 17 , further comprising discharging the airflow from the second opposing end of the rotating hollow rotatable outlet shaft through a radial cross-sectional area between the rotating outlet shaft and the cylindrical air guide. 
     
     
       19. A gas turbine engine including a core engine, a compressor, a high pressure turbine, a low pressure turbine, a combustor assembly, a fan, and a rotor, said gas turbine engine comprising:
 an air/oil separator comprising: 
 a drive shaft having a central axis extending in an axial direction, said drive shaft coupled with said gas turbine engine rotor; 
 a free vortex chamber mounted radially around said drive shaft; 
 a separation chamber coupled with said free vortex chamber in said axial direction on a side of said free vortex chamber opposite to said drive shaft; 
 a rotatable outlet shaft having an inlet end, an outlet end, and a hollow interior chamber therebetween, said hollow interior chamber having an inner circumference extending in the axial direction, said inlet end coupled with said separation chamber on a side of said separation chamber opposite to said free vortex chamber, and said rotatable outlet shaft radially rotatable around the axial direction; and 
 a cylindrical air guide comprising; 
 a nonporous cylindrical main body having an outer circumference extending coaxially within said inner circumference of said hollow interior chamber of said rotatable outlet shaft, said nonporous cylindrical main body having a cylindrical outer wall with a smooth, uninterrupted outer surface, and wherein said nonporous cylindrical main body is hollow inside of said cylindrical outer wall; 
 an upstream end fixedly coupled with said inlet end of said rotatable outlet shaft; and 
 a downstream end coaxially disposed within said outlet end of said rotatable outlet shaft. 
 
     
     
       20. The gas turbine engine of  claim 19 , further comprising a gearbox, wherein said drive shaft is radially coupled with said gearbox.