Gas turbine engine with acoustic spacing of the fan blades and outlet guide vanes

Patent metadata

Field	Value
Publication number	US-2025382919-A1
Application number	US-202519197884-A
Country	US
Kind code	A1
Filing date	May 2, 2025
Priority date	Jun 14, 2024
Publication date	Dec 18, 2025
Grant date	—

Abstract

A gas turbine engine comprises a fan, a core turbine engine coupled to the fan, a fan case housing the fan and the core turbine engine, a plurality of outlet guide vanes extending between the core turbine engine and the fan case, and an acoustic spacing. The fan blades feature a low aspect ratio, reducing blade count while maintaining thrust and efficiency. Efficiency is enhanced through a determined relationship between fan blade count, aspect ratio, and specific flow.

First claim

We claim:

1 . A gas turbine engine comprising:
a core turbine engine comprising a low pressure turbine; a gearbox assembly coupled to the low pressure turbine, the gearbox assembly having a gear ratio within a range of 2.5 to 6.0; a fan coupled to the gearbox assembly and having a fan diameter, a fan area, and a plurality of composite fan blades that have a chord length c 1 at a 75% span position and a chord length c 2 at a 50% span position; a blade effective acoustic length (BEAL) defined as:

BEAL
=

2
⁢
c
⁢

1
2

S
⁡
(

1
-

r
⁢
r

)

⁢

N
b

⁢

cos
⁡
(
γ
)

wherein S is a span of the fan blade, rr is a radius ratio of the fan, γ is a stagger angle of the fan blade, and N b is the number of the plurality of composite fan blades;
a nacelle that includes a fan case that surrounds the fan, the fan case comprising an inlet disposed forward of the fan and an inlet length, wherein the inlet length is an axial distance between a leading edge of one of the plurality of fan blades and the inlet, as measured at the 75% span position;
a plurality of outlet guide vanes disposed aft of the fan and extending radially between the core turbine engine and the fan case;
an acoustic spacing from the fan blade trailing edge to an outlet guide vane leading edge;
an acoustic spacing ratio (ASR) defined as:

ASR
=

1

(

N
⁢
v

N
⁢
b

)

·

A
⁢
s

B
⁢
E
⁢
A
⁢
L

wherein As is the acoustic spacing and Nv is the number of the plurality of outlet guide vanes;
an inlet-to-nacelle (ITN) ratio defined as a ratio of the inlet length to a maximum diameter of the nacelle,
wherein the ASR of the gas turbine engine is 1.5 to 16.0, and the ITN ratio is 0.23 to 0.35 and
wherein the gas turbine engine is characterized by an improved fan assembly efficiency in which the following relationship applies:

15
<

N
b

*
A
⁢
R
*
5
⁢
0

SF

<

6
⁢
0

wherein AR is a fan blade aspect ratio, and SF is a fan specific flow, and the fan blade aspect ratio (AR) is determined from S/c 2 , and the fan specific flow (SF) is determined from MF/FA, where MA is a mass flow of the fan and FA is a fan area.

2 . The gas turbine engine of claim 1 , wherein the plurality of composite fan blades have with a blade solidity that is greater than or equal to 0.8 and less than or equal to 2.0.

3 . The gas turbine engine of claim 1 , wherein the number of composite fan blades (Nb) ranges from 10 to 26.

4 . The gas turbine engine of claim 1 , wherein the number of composite fan blades (Nb) ranges from 12 to 22.

5 . The gas turbine engine of claim 1 , wherein the fan blade aspect ratio (AR) ranges from 1.3 to 2.2.

6 . The gas turbine engine of claim 1 , wherein the number of composite fan blades (Nb) ranges from 12 to 18.

7 . The gas turbine engine of claim 6 , wherein the fan blade aspect ratio (AR) ranges from 1.5 to 1.9.

8 . The gas turbine engine of claim 1 , wherein the gearbox assembly has a gear ratio ranging from 2.7 to 4.0.

9 . The gas turbine engine of claim 1 , further comprising a disk-to-blade diametric (DBD) ratio defined as a ratio of a disk spacing length to the fan diameter, the disk spacing length being a distance between a forwardmost end of a fan disk and an intersection with the inlet taken along an engine centerline,
wherein the DBD ratio of the gas turbine engine is 0.09 to 0.59.

10 . The gas turbine engine of claim 9 , wherein the DBD ratio of the gas turbine engine is 0.15 to 0.35.

11 . The gas turbine engine of claim 9 , wherein the DBD ratio of the gas turbine engine is 0.19 to 0.27.

12 . The gas turbine engine of claim 1 , wherein the gas turbine engine is characterized by an improved fan assembly efficiency in which the following relationship applies:

19.5
<

N
b

*
A
⁢
R
*
5
⁢
0

S
⁢
F

<

4
⁢

7
.
2
.

13 . The gas turbine engine of claim 1 , wherein the gas turbine engine is characterized by an improved fan assembly efficiency in which the following relationship applies:

2
⁢
8

<

N
b

*
A
⁢
R
*

Assignees

• Gen Electric

Inventors

• Miller Brandon Wayne
• Geertsema Egbert
• Sibbach Arthur W
• Hudecki Andrew
• Depuy Timothy Richard
• Schilling John C
• Worthoff Frank
• Nakano Tsuguji

Classifications

• F02C7/36 Primary

  Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) · CPC title

• F02C7/24

  Heat or noise insulation (air intakes having provisions for noise suppression F02C7/045; turbine exhaust heads, chambers, or the like F01D25/30; silencing nozzles of jet-propulsion plants F02K1/00) · CPC title

• F02K3/06

  with front fan · CPC title

• F05D2260/961

  by mistuning rotor blades or stator vanes with irregular interblade spacing, airfoil shape · CPC title

• F05D2260/96

  Preventing, counteracting or reducing vibration or noise · CPC title