Gas turbine engine with third stream

Patent metadata

Field	Value
Publication number	US-11859516-B2
Application number	US-202217896579-A
Country	US
Kind code	B2
Filing date	Aug 26, 2022
Priority date	Sep 3, 2021
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

A gas turbine engine defining a centerline and a circumferential direction, the gas turbine engine including: a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining a working gas flowpath and a fan duct flowpath; a primary fan driven by the turbomachine defining a primary fan tip radius R 1 and a primary fan hub radius R 2 ; a secondary fan located downstream of the primary fan and driven by the turbomachine, at least a portion of an airflow from the primary fan configured to bypass the secondary fan, the secondary fan defining a secondary fan tip radius R 3 and a secondary fan hub radius R 4 , wherein the secondary fan is configured to provide a fan duct airflow through the fan duct flowpath during operation to generate a fan duct thrust, wherein the fan duct thrust is equal to % Fn 3S of a total engine thrust during operation of the gas turbine engine at a rated speed during standard day operating conditions; wherein a ratio of R 1 to R 3 equals

(
EFP
)

⁢

(

1
-

R
⁢
q
⁢

R

Sec
.

-

Fan
2

)

(

1
-

R
⁢
q
⁢

R

Prim
.

-
Fa

⁢

n
2

)

⁢

(

1

%
⁢

Fn

3
⁢
S

-
1

)

;

wherein EFP is between 1.5 and 11, wherein RqR Prim.-Fan is a ratio of R 1 to R 2 , and wherein RqR Sec.-Fan is a ratio of R 3 to R 4 .

First claim

I claim:

1. A gas turbine engine defining a centerline and a circumferential direction, the gas turbine engine comprising:
a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining a working gas flowpath and a fan duct flowpath;
a primary fan driven by the turbomachine defining a primary fan tip radius R 1 and a primary fan hub radius R 2 ; and
a secondary fan located downstream of the primary fan and driven by the turbomachine, at least a portion of an airflow from the primary fan configured to bypass the secondary fan, the secondary fan defining a secondary fan tip radius R 3 ;
wherein a ratio of R 1 to R 3 is between 2 and 7.

2. The gas turbine engine of claim 1 , wherein the ratio of R 1 to R 3 is between 3 and 7.

3. The gas turbine engine of claim 1 , wherein the ratio of R 1 to R 3 is between 5 and 7.

4. The gas turbine engine of claim 1 , wherein R 1 is at least 5 feet and up to 14 feet.

5. The gas turbine engine of claim 1 , wherein R 1 is at least 6 feet and up to 12 feet.

6. The gas turbine engine of claim 1 , wherein the primary fan comprises at least 10 fan blades and up to 18 fan blades.

7. The gas turbine engine of claim 1 , wherein the turbine section comprises a low pressure turbine, wherein the low pressure turbine comprises between 3 stages and 7 stages.

8. The gas turbine engine of claim 1 , wherein the turbine section comprises a low pressure turbine, wherein the low pressure turbine comprises 4 stages.

9. The gas turbine engine of claim 1 , wherein the turbomachine comprises a gearbox, and wherein the turbomachine is configured to drive the primary fan across the gearbox.

10. The gas turbine engine of claim 9 , wherein the gearbox defines a gear ratio of an input rotational speed to an output rotational speed greater than 4.1:1.

11. The gas turbine engine of claim 1 , wherein RqR Prim.-Fan is a ratio of R 2 to R 1 , wherein RqR Prim.-Fan is between 0.2 and 0.4.

12. The gas turbine engine of claim 1 , wherein the secondary fan further defines a secondary fan hub radius R 4 , wherein RqR Sec.-Fan is a ratio of R 4 to R 3 , wherein RqR Sec.-Fan is between 0.2 and 0.8.

13. The gas turbine engine of claim 1 , wherein the primary fan defines a primary fan corrected tip speed during operation of the gas turbine engine at the rated speed during standard day operating conditions, wherein the secondary fan defines a secondary fan corrected tip speed during operation of the gas turbine engine at the rated speed during standard day operating conditions, wherein the primary fan corrected tip speed is between 500 feet per second and 2,000 feet per second, and wherein the secondary fan corrected tip speed is between 500 feet per second and 2,000 feet per second.

14. The gas turbine engine of claim 1 , wherein the fan duct flowpath defines an outlet, and wherein the gas turbine engine further comprises:
a variable geometry component associated with the secondary fan, wherein the variable geometry component is a stage of variable inlet guide vanes located immediately upstream of the secondary fan, a variable exhaust nozzle located at the outlet of the fan duct flowpath, or both.

15. The gas turbine engine of claim 1 , wherein the primary fan is an unducted fan.

16. The gas turbine engine of claim 15 , wherein the gas turbine engine defines a bypass airflow passage, wherein the primary fan is configured to provide a first portion of a primary fan airflow to the bypass airflow passage and a second portion of the primary fan airflow to the secondary fan, and wherein the secondary fan is configured to provide a first portion of a secondary fan airflow to the fan duct flowpath as the fan duct airflow and a second portion of the secondary fan airflow to the working gas flowpath.

17. The gas turbine engine of claim 1 , further comprising:
a heat exchanger positioned in thermal communication with the fan duct flowpath.

18. The gas turbine engine of claim 1 , wherein the secondary fan is configured to provide a fan duct airflow through the fan duct flowpath during operation to generate a fan duct thrust, wherein the fan duct thrust is equal to % Fn 3S of a total engine thrust during operation of the gas turbine engine at a rated speed during standard day operating conditions, wherein % Fn 3S is between 1% and 50%.

19. The gas turbine engine of claim 18 , wherein % Fn 3S is between 3% and 30%.

20. The gas turbine engine of claim 18 , wherein % Fn 3S is between 5% and 20%.

21. A gas turbine engine defining a centerline and a circumferential direction, the gas turbine engine comprising:
a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining a working gas flowpath and a fan duct flowpath;
a primary fan driven by the turbomachine defining a primary fan tip radius R 1 and a primary fan hub radius R 2 ;
a secondary fan located downstream of the primary fan and driven by the turbomachine, at least a portion of an airflow from the primary fan configured to bypass the secondary fan, the secondary fan defining a secondary fan tip radius R 3 and a secondary fan hub radius R 4 , wherein the secondary fan is configured to provide a fan duct airflow through the fan duct flowpath during operation to generate a fan duct thrust, wherein the fan duct thrust is equal to % Fn 3S of a total engine thrust during operation of the gas turbine engine at a rated speed during standard day operating conditions;
wherein % Fn 3S is between 1% and 50%, and wherein a ratio of R 1 to R 3 is between 2 and 7.

22. The gas turbine engine of claim 21 , wherein % Fn 3S is between 3% and 30%.

23. A gas turbine engine defining a centerline and a circumferential direction, the gas turbine engine comprising:
a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining a working gas flowpath and a fan duct flowpath;
a primary fan driven by the turbomachine defining a primary fan tip radius R 1 and a primary fan hub radius R 2 ;
a secondary fan located downstream of the primary fan and driven by the turbomachine, at least a portion of an airflow from the primary fan configured to bypass the secondary fan, the secondary fan defining a secondary fan tip radius R 3 and a secondary fan hub radius R 4 , wherein the secondary fan is configured to provide a fan duct airflow through the fan duct flowpath during operation to generate a fan duct thrust, wherein the fan duct thrust is equal to % Fn 3S of a total engine thrust during operation at a rated speed during standard day operating conditions;
wherein a ratio of R 1 to R 3 equals

(
EFP
)

⁢

(

1
-

R
⁢
q
⁢

R

Sec

Assignees

• Gen Electric

Inventors

• Ostdiek David Marion

Classifications

• F05D2240/30

  Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor · CPC title

• F02K3/06

  with front fan · CPC title

• B64D2027/005

  Aircraft with an unducted turbofan comprising contra-rotating rotors, e.g. contra-rotating open rotors [CROR] · CPC title

• B64C11/48

  Units of two or more coaxial propellers · CPC title

• F01D9/041 Primary

  using blades (F01D5/148 takes precedence) · CPC title