Centrifugal compressor diffuser and method for controlling same

Patent metadata

Field	Value
Publication number	US-9803652-B2
Application number	US-201414176253-A
Country	US
Kind code	B2
Filing date	Feb 10, 2014
Priority date	Feb 10, 2014
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

A centrifugal compressor having at least a diffuser is disclosed. The diffuser has an annular diffuser body having circumferentially spaced apart diffuser passages defining fluid paths through the diffuser body. The diffuser also has a plurality of diffusion members mounted to the annular diffuser body. Each diffusion member has a member inlet in fluid communication with a diffuser passage and a member outlet. Each diffusion member defines an aerodynamic throat disposed between the member inlet and the member outlet. The diffuser also has a fluid injection assembly with multiple injection conduits. Each injection conduit extends between a conduit inlet configured to receive a flow of compressible fluid from a supply and a conduit outlet communicating with a corresponding diffusion member downstream of the aerodynamic throat. The compressible fluid is injected through the conduit outlet into the diffusion members.

First claim

The invention claimed is:

1. An assembly having a diffuser for diffusing gases radially received from a radial outlet of a centrifugal compressor including an impeller having an inner hub with vanes thereon, the impeller adapted to rotate within an outer shroud about a central longitudinal axis, the assembly comprising:
an annular diffuser body having a plurality of circumferentially spaced apart diffuser passages at least partially defining fluid paths through the diffuser body, the diffuser passages each having a passage inlet in fluid communication with the radial outlet of the compressor, and a passage outlet;
a plurality of diffusion members mounted to the annular diffuser body, each diffusion members having a member inlet in fluid communication with the passage outlet of a corresponding diffuser passage and a member outlet, each diffusion member defining an aerodynamic throat disposed between the member inlet and the member outlet; and
a fluid injection assembly having a plurality of injection conduits, each injection conduit extending between a conduit inlet configured to receive a flow of compressible fluid from a supply and a conduit outlet communicating with a corresponding diffusion member downstream of the aerodynamic throat relative to a direction of a main gas flow through said diffusion member.

2. The assembly as defined in claim 1 , wherein the diffusion members are diffuser pipes, each diffuser pipe having a first section beginning at the member inlet and extending away therefrom, a second section extending substantially parallel to the central axis along a second section length terminating at the member outlet of the diffuser pipe, and a curved section in fluid communication with the first and second sections and disposed downstream of the first section and upstream of the section sections, the throat of each diffuser pipe being disposed in at least one of the first and the curved sections.

3. The assembly as defined in claim 2 , wherein the throat of each diffuser pipe is disposed in the first section, the conduit outlets of the injection conduits opening into corresponding diffuser pipes within the first section downstream of the throat.

4. The assembly as defined in claim 1 , wherein at least one injection conduit has a convergent duct extending between the conduit inlet and the conduit outlet.

5. The assembly as defined in claim 4 , wherein the convergent duct is oriented substantially parallel to a flow of the main gas flow in said diffusion member.

6. The assembly as defined in claim 1 , wherein the conduit outlet of at least one injection conduit is an injection slot extending through a wall of said diffusion member.

7. The assembly as defined in claim 1 , wherein the supply is disposed downstream of the member outlets of the diffusion members in a region of the compressor having P3 air, the P3 air having a static pressure greater than a static pressure at the conduit inlets of the injection conduits, the P3 air circulating passively from the supply to the conduit inlets of the injection conduits.

8. A method for controlling a centrifugal compressor, the centrifugal compressor including an impeller which feeds a main gas flow into a diffuser downstream therefrom, the method comprising:
directing the main gas flow through a plurality of diffusion members of the diffuser between an inlet and an outlet thereof; and
injecting a compressible fluid into the main gas flow in the diffusion members at a location downstream of an aerodynamic throat of each of the diffusion members.

9. The method as defined in claim 8 , wherein injecting the compressible fluid comprises injecting the compressible fluid upstream of redirecting the main gas flow in each diffusion member.

10. The method as defined in claim 8 , wherein injecting the compressible fluid further comprises converging a flow of the compressible fluid prior to injecting it into each of the diffusion members.

11. The method as defined in claim 8 , wherein injecting the compressible fluid further comprises injecting the compressible fluid into each of the diffusion members along a direction substantially parallel to a direction of the main gas flow within each of the diffusion members.

12. The method as defined in claim 8 , wherein injecting the compressible fluid further comprises drawing the compressible fluid from a supply of P3 air downstream of the diffusion members.

13. The method as defined in claim 12 , wherein drawing the compressible fluid comprises circulating P3 air passively from the supply to each of the diffusion members.

14. The method as defined in claim 12 , wherein drawing the compressible fluid comprises pumping the compressible fluid from the supply to each of the diffusion members.

15. A centrifugal compressor, comprising:
an impeller having an inner hub with vanes thereon and adapted to rotate within an outer shroud about a central longitudinal axis, the impeller having a radial impeller outlet; and
a diffuser assembly for diffusing gases radially received from the impeller outlet, comprising:
an annular diffuser body having a plurality of circumferentially spaced apart diffuser passages at least partially defining fluid paths through the diffuser body, the diffuser passages each having a passage inlet in fluid communication with the impeller outlet and a passage outlet;
a plurality of diffusion members mounted to the annular diffuser body, each diffusion member having a member inlet in fluid communication with the passage outlet of a corresponding diffuser passage and a member outlet, each diffusion member defining an aerodynamic throat disposed between the member inlet and the member outlet; and
a fluid injection assembly having a plurality of injection conduits, each injection conduit extending between a conduit inlet configured to receive a flow of compressible fluid from a supply and a conduit outlet communicating with a corresponding diffusion member downstream of the aerodynamic throat relative to a direction of a main gas flow through said diffusion member.

16. The compressor as defined in claim 15 , wherein the diffusion members are diffuser pipes, each diffuser pipe having a first section beginning at the member inlet and extending away therefrom, a second section extending substantially parallel to the central axis along a second section length terminating at the member outlet, and a curved section in fluid communication with the first and second sections and disposed downstream of the first section and upstream of the section sections, the aerodynamic throat of each diffusion member being disposed in at least one of the first and the curved sections.

17. The compressor as defined in claim 15 , wherein at least one injection conduit has a convergent duct extending between the conduit inlet and the conduit outlet.

18. The compressor as defined in claim 17 , wherein the convergent duct is oriented substantially parallel to a flow of the main gas flow in said diffusion member.

19. The compressor as defined in claim 15 , wherein the conduit outlet of at least one injection conduit is an injection slot extending through a wall of said diffusion member.

20. The compressor as defined in claim 15 , wherein the supply is disposed downstream of the pipe outlets of the diffusion members in a region of the compressor having P3 air, the P3 air having a static pressure greater than a static pressure at the conduit inlets of the injection conduits, the P3 air circulating passively from the supply to the conduit inlets of the injection

Assignees

• Pratt & Whitney Canada

Inventors

• Duong Hien
• Townsend Peter
• Kandasamy Vijay
• Upadrasta Koundinya

Classifications

• F05D2250/52

  Outlet · CPC title

• F04D29/684

  by fluid injection · CPC title

• F04D29/441 Primary

  especially adapted for elastic fluid pumps · CPC title

• F04D27/0207

  by bleeding, bypassing or recycling fluids (influencing the boundary layer by an uncontrolled bleeding of the working fluid F04D29/681) · CPC title

• F04D29/681

  especially adapted for elastic fluid pumps · CPC title