Turbine engine having improved thrust bearing load control

• US 5,862,666 A
• Filed: 12/23/1996
• Issued: 01/26/1999
• Est. Priority Date: 12/23/1996
• Status: Expired due to Term

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Liu, Xiaoliu
• Primary Examiner(s): Casaregola, Louis J.
• Application Number:
  US08/771,906
• Time in Patent Office: 764 Days
• Field of Search: 60/39.75, 60/726, 415/104, 415/105, 415/106, 415/107
• US Class Current: 60/726
• CPC Class Codes: F01D 3/00 Machines or engines with axial-thrust balancing effected by working-fluid
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A modified turbine engine design in which control of the forward load on a thrust bearing is improved, while reducing or eliminating the need for the use of a balance piston is disclosed. The turbine engine has a longitudinal axis and comprises, a compressor for pressurizing gases in the engine. The impeller has an impeller rear face and a tip. The engine further comprises a shaft mounted to a thrust bearing for rotation about the axis. The impeller is fixed to the shaft for rotation therewith. A cavity fixed within the engine casing is defined at least by the impeller rear face and is in communication with the pressurized gases at the impeller tip. The engine further comprises a bleed in communication with both the cavity and the pressurized gases, so that the cavity is pressurized by the pressurized gases from the impeller tip and the bleed, thereby loading the impeller rear face to load the thrust bearing through the shaft. Preferably, the pressurized gases from the bleed reduce flow swirl in the cavity and thereby increase the pressure in the cavity.

Claims

1. A turbine engine within an engine casing, said turbine engine hating a longitudinal axis, said turbine engine comprising:

a compressor comprising an impeller, said impeller having an impeller rear face and an impeller tip, said compressor for pressurizing gases in said turbine engine;

a shaft mounted to a thrust bearing for rotation about said axis, said impeller fixed to said shaft for rotation therewith;

a combustion section in flow communication with pressurized gases from said compressor;

a cavity fixed within said engine casing and defined at least by said impeller rear face and in flow communication at said impeller tip with pressurized gases from said impeller tip, said impeller tip gases having a tangential velocity about said axis within said cavity; and

a bleed in flow communication between said cavity and said combustion section with pressurized gases from said combustion section, said bleed adapted to guide the flow of said combustion section gases to reduce said tangential velocity of said impeller tip gases in said cavity, said cavity pressurized by pressurized gases from said impeller tip and from said bleed, thereby loading said impeller rear face to load said thrust bearing through said shaft.

2. The turbine engine of claim 1 wherein said cavity extends to said impeller tip and wherein said bleed opens proximate said impeller tip.

3. The turbine engine of claim 2 further comprising:

an air diffuser pipe extending from said impeller tip to said combustion section, said air diffuser pipe providing said flow communication between said compressor and said combustion section, said air diffuser pipe adapted to reduce said tangential velocity of said gases from said impeller tip to said combustion section.

wherein said bleed is in communication with gases from said diffuser pipe.

4. The turbine engine of claim 2 wherein said bleed comprises a plurality of passageways from said combustion section to said cavity.

5. The turbine engine of claim 4 wherein said passageways extend generally perpendicular to said impeller rear face.

6. The turbine engine of claim 1 wherein said bleed extends from a high pressure region of said combustion section.

7. A turbine engine comprising, within an engine casing:

a compressor section comprising an impeller, said impeller having a tip;

a combustion section in flow communication with pressurized gases from said compressor section;

a turbine;

a shaft mounted for rotation about a longitudinal axis connecting said impeller to said turbine;

a thrust bearing about said shaft, mounted to said casing to limit movement of said shaft along and transversely of said axis;

said compressor section defining a cavity between said impeller and said turbine, said cavity in flow communication at said impeller tip with pressurized gases from said impeller tip; and

a bleed in flow communication between said cavity and said combustion section, said bleed proximate said impeller tip for bleeding pressurized gases from said combustion section to said cavity to pressurize said cavity to urge said impeller, and therefore said shaft toward a first position.

8. The turbine engine of claim 7 further comprising an air diffuser pipe extending from said impeller tip and in fluid communication with said combustion section for guiding air from said impeller into said combustion section and for reducing tangential velocity of said impeller air.

9. The turbine engine of claim 8 wherein said bleed comprises a plurality of passageways from said combustion section to said cavity.

10. The turbine engine of claim 7 wherein said bleed extends from a high pressure region of said combustion section.

11. A turbine engine comprising, within an engine casing:

a compressor section comprising an impeller having an impeller tip;

a combustion section, defined by a combustion section wall;

a turbine;

a shaft mounted for rotation about a central, longitudinal axis connecting said impeller to said turbine;

a thrust bearing about said shaft, mounted to said casing to limit movement of said shaft along and away from said axis;

said compressor section defining a cavity between said impeller and said combustion section; and

said combustion section wall having a bleed inlet to said cavity, proximate said impeller tip for bleeding pressurized air from said combustion section into said cavity, to pressurize said cavity to urge said impeller, and therefore said shaft toward a first position.

12. The turbine engine of claim 11 further comprising an air diffuser pipe extending from said impeller tip, having an outlet in fluid communication with said combustion section for guiding air from said impeller into said combustion section and for reducing tangential velocity of said air from said impeller, and wherein said bleed inlet extends through said combustion section wall proximate said outlet.