Midshaft rating for turbomachine engines

Patent metadata

Field	Value
Publication number	US-12215633-B2
Application number	US-202318486523-A
Country	US
Kind code	B2
Filing date	Oct 13, 2023
Priority date	May 24, 2021
Publication date	Feb 4, 2025
Grant date	Feb 4, 2025

Abstract

A turbomachine engine includes a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine also includes a shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec) 1/2 and three hundred (ft/sec) 1/2 . In one aspect, the shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). In another aspect, the shaft has a length L, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

First claim

The invention claimed is:

1. A method of operating a turbomachine engine including a power turbine and a shaft that is coupled to the power turbine, the method comprising:
driving the shaft, wherein the shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec) 1/2 and three hundred (ft/sec) 1/2 ; and
operating the turbomachine engine up to a redline speed without passing through a critical speed associated with a first-order bending mode of the shaft.

2. The method of claim 1 , wherein the MSR is between two hundred (ft/sec) 1/2 and two hundred forty-five (ft/sec) 1/2 .

3. The method of claim 1 , wherein the MSR is between two hundred twelve (ft/sec) 1/2 and two hundred sixty (ft/sec) 1/2 .

4. The method of claim 1 , wherein the MSR is between two hundred forty-seven (ft/sec) 1/2 and two hundred eighty-seven (ft/sec) 1/2 .

5. The method of claim 1 , wherein the redline speed is between fifty ft/sec and two hundred fifty ft/sec.

6. The method of claim 1 , wherein the redline speed is between sixty ft/sec and ninety ft/sec.

7. The method of claim 1 , wherein the redline speed is between seventy-five ft/sec and one hundred seventy-five ft/sec.

8. The method of claim 1 , wherein the redline speed is between one hundred fifty ft/sec and two hundred fifty ft/sec.

9. The method of claim 1 , wherein the shaft is supported between a first bearing and a second bearing, and the shaft has a length L defined between the first bearing and the second bearing, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

10. The method of claim 9 , wherein the ratio of L/D is between sixteen and thirty.

11. The method of claim 9 , wherein the ratio of L/D is between twenty-six and thirty-seven.

12. The method of claim 1 , wherein the shaft is a low-speed shaft, and the turbomachine engine further includes a high-pressure compressor, a high-pressure turbine, and a high-speed shaft that couples the high-pressure compressor and the high-pressure turbine, and the method further comprises driving the high-speed shaft with the high-pressure turbine to rotate the high-pressure compressor.

13. The method of claim 12 , wherein the turbomachine engine further includes a combustion chamber, and the method further comprises combusting fuel and air in the combustion chamber to generate combustion gases, and driving the high-pressure turbine and the power turbine with the combustion gases.

14. The method of claim 1 , wherein the turbomachine engine further includes a fan assembly, and the shaft is coupled to the fan assembly, and the method further comprises driving, by the power turbine, the fan assembly via the shaft.

15. The method of claim 14 , wherein the turbomachine engine further includes a power gearbox that couples the fan assembly to the shaft, and the method further comprises decreasing, with the power gearbox, a rotational speed of the fan assembly relative to the shaft.

16. A method of operating a turbomachine engine including a fan assembly, a high-pressure compressor, a high-pressure turbine, a high-speed shaft that couples the high-pressure compressor and the high-pressure turbine, and a combustion chamber that is in flow communication with the high-pressure compressor and the high-pressure turbine, a power turbine that is in flow communication with the high-pressure turbine, and a low-speed shaft that is coupled to the power turbine and the fan assembly, the method comprising:
combusting fuel and air in the combustion chamber to generate combustion gases;
driving the high-pressure turbine with the combustion gases;
driving the high-pressure compressor with the high-pressure turbine via the high-speed driving the power turbine with the combustion gases;
shaft;
driving the fan assembly with the power turbine via the low-speed shaft;
driving the low-speed shaft, wherein the low-speed shaft is characterized by a midshaft rating (MSR) between two hundred (ft/sec) 1/2 and three hundred (ft/sec) 1/2 ; and
operating the turbomachine engine up to a redline speed without passing through a critical speed associated with a first-order bending mode of the low-speed shaft.

17. The method of claim 16 , wherein the MSR is between two hundred (ft/sec) 1/2 and two hundred forty-five (ft/sec) 1/2 .

18. The method of claim 16 , wherein the redline speed is between fifty ft/sec and two hundred fifty feet per second ft/sec.

19. The method of claim 16 , wherein the low-speed shaft is supported between a first bearing and a second bearing, and the low-speed shaft has a length L defined between the first bearing and the second bearing, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

20. The method of claim 16 , wherein the turbomachine engine further includes a power gearbox that couples the fan assembly to the low-speed shaft, and the method further comprises decreasing, with the power gearbox, a rotational speed of the fan assembly relative to the low-speed shaft.

Assignees

• Gen Electric

Inventors

• Payyoor Narayanan
• Kang Weize
• Becker Thomas Lee
• Schmidt Richard

Classifications

• F05D2300/603

  Composites; e.g. fibre-reinforced · CPC title

• F05D2250/711

  convex · CPC title

• F05D2240/61

  Hollow · CPC title

• F05D2240/54

  Radial bearings · CPC title

• F02C7/06 Primary

  Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M) · CPC title