Turboshaft gas turbine engine

Patent metadata

Field	Value
Publication number	US-12098644-B2
Application number	US-202218056032-A
Country	US
Kind code	B2
Filing date	Nov 16, 2022
Priority date	Aug 8, 2018
Publication date	Sep 24, 2024
Grant date	Sep 24, 2024

Abstract

A turboshaft engine for a rotorcraft includes a first spool and an independently rotatable second spool. The first spool includes a low pressure compressor, a first set of variable guide vanes disposed at an entry of the low pressure compressor, and a low pressure turbine drivingly engaged to the low pressure compressor. The second spool includes a high pressure compressor, a second set of variable guide vanes disposed at an entry of the high pressure compressor, the second set of variable guide vanes independently operable relative to the first set of variable guide vanes, and a high pressure turbine drivingly engaged to the high pressure compressor. One or both of the low pressure compressor and the high pressure compressor includes a mixed flow rotor.

First claim

The invention claimed is:

1. A turboshaft engine for a rotorcraft, the turboshaft engine comprising:
a first spool having a low pressure compressor in fluid communication with an air inlet, a first set of variable guide vanes disposed at an entry of the low pressure compressor, and a low pressure turbine drivingly engaged to the low pressure compressor;
a second spool independently rotatable relative to the first spool, the second spool having a high pressure compressor in fluid communication with the low pressure compressor to receive pressurized air therefrom, a second set of variable guide vanes disposed at an entry of the high pressure compressor, the second set of variable guide vanes independently operable relative to the first set of variable guide vanes, and a high pressure turbine drivingly engaged to the high pressure compressor; and
an output shaft drivingly engaged to the low pressure turbine, the output drive shaft adapted to drivingly engage a rotatable load of the turboshaft engine;
wherein both of the low pressure compressor and the high pressure compressor include a mixed flow rotor.

2. The turboshaft engine as defined in claim 1 , wherein the mixed flow rotor in one or both of the low pressure compressor and the high pressure compressor is located immediately downstream of a respective one of the first set of variable guide vanes and the second set of variable guide vanes.

3. The turboshaft engine as defined in claim 1 , wherein the first set of variable guide vanes is operable between an 80 degree position and a −25 degree position associated with the first set of variable guide vanes.

4. The turboshaft engine as defined in claim 3 , wherein the second set of variable guide vanes is operable between an 80 degree position and a −25 degree position associated with the second set of variable guide vanes.

5. The turboshaft engine as defined in claim 1 , wherein the first set of variable guide vanes is operable between an 80 degree position and a −25 degree position associated with the first set of variable guide vanes while the second set of variable guide vanes is maintained in a given position.

6. The turboshaft engine as defined in claim 1 , wherein the high pressure turbine includes only a single turbine stage.

7. The turboshaft engine as defined in claim 1 , wherein the low pressure compressor includes only the single mixed flow rotor.

8. The turboshaft engine as defined in claim 1 , wherein the high pressure compressor includes a centrifugal compressor.

9. A turboshaft engine for a rotorcraft, the turboshaft engine comprising:
at least two spools independently rotatable relative to each other, a low pressure spool of the at least two spools including a low pressure shaft interconnecting a low pressure compressor section to a low pressure turbine section, and a high pressure spool of the at least two spools including a high pressure shaft interconnecting a high pressure compressor section to a high pressure turbine section, both of the low pressure compressor section and the high pressure compressor section including a mixed flow rotor; and
means for controlling an airflow through the low pressure compressor section independently of the high pressure compressor section.

10. The turboshaft engine as defined in claim 9 , wherein said means for controlling including means for independently operating a first set of variable guide vanes and a second set of variable guide vanes.

11. The turboshaft engine as defined in claim 10 , wherein the first set of variable guide vanes is disposed upstream of the low pressure compressor section and the second set of variable guide vanes is disposed upstream of the high pressure compressor, vanes of the first set of variable guide vanes being moveable independently from vanes of the second set of variable guide vanes.

12. The turboshaft engine as defined in claim 9 , wherein said means is configured to modulate the first set of variable guide vanes between an 80 degree position and a −25 degree position.

13. The turboshaft engine as defined in claim 12 , wherein said means is configured to modulate the second set of variable guide vanes between an 80 degree position and a −25 degree position.

14. The turboshaft engine as defined in claim 9 , wherein the low pressure compressor includes only the single mixed flow rotor.

15. The turboshaft engine as defined in claim 9 , wherein the high pressure compressor includes a centrifugal compressor.

16. A method for operating a turboshaft engine for a rotorcraft, the method comprising:
drawing air into a core of the turboshaft engine through a low pressure compressor section and then through a high pressure compressor section located downstream from the low pressure compressor section to provide pressurized air, the low pressure compressor section rotating independently of the high pressure compressor section, both of the low pressure compressor section and the high pressure compressor section including a mixed flow rotor;
operating a first set of variable guide vanes disposed upstream of the low pressure compressor section;
independently of operating the first set of variable guide vanes, operating a second set of variable guide vanes disposed upstream of the high pressure compressor;
igniting a mixture of the pressurized air and fuel to generate combustion gases;
directing the combustion gases through a high pressure turbine section and then through a low pressure turbine section to drive the high pressure turbine section and the low pressure turbine section using the combustion gases;
driving the high pressure compressor section with the high pressure turbine section; and
driving the low pressure compressor section and a rotatable load with the low pressure turbine section, the low pressure turbine section and the high pressure turbine section rotating independently from one another.

17. The method as defined in claim 16 , wherein operating the first set of variable guide vanes includes modulating the first set of variable guide vanes between one of: an 80 degree position and a −25 degree position; a 75 degree position and a −20 degree position.

18. The method as defined in claim 17 , wherein operating the second set of variable guide vanes includes one of: modulating the second set of variable guide vanes between an 80 degree position and a −25 degree position; and maintaining the second set of variable guide vanes in a given position.

19. The method as defined in claim 16 , wherein drawing air through the low pressure compressor section includes drawing air through the single mixed flow rotor in the low pressure compressor section.

20. The method as defined in claim 16 , wherein drawing air through the high pressure compressor section includes drawing air through a centrifugal compressor in the high pressure compressor section.

Assignees

• Pratt & Whitney Canada

Inventors

• Morgan Keith
• Durocher Eric

Classifications

• B64D35/08

  characterised by the transmission being driven by a plurality of power plants (for hybrid-electric power plants B64D35/022) · CPC title

• B64D31/00

  Power plant control systems; Arrangement of power plant control systems in aircraft · CPC title

• F01D13/02 Primary

  Working-fluid interconnection of machines or engines · CPC title

• F01D13/003 Primary

  with at least two independent shafts, i.e. cross-compound · CPC title

• F05D2260/4031

  as in toothed gearing · CPC title