U.S. patent application number 13/251502 was filed with the patent office on 2013-04-04 for strut rods for structural guide vanes.
This patent application is currently assigned to UNITED TECHNOLOGIES CORPORATION. The applicant listed for this patent is John C. DiTomasso, Fadi S. Maalouf. Invention is credited to John C. DiTomasso, Fadi S. Maalouf.
Application Number | 20130084174 13/251502 |
Document ID | / |
Family ID | 46888927 |
Filed Date | 2013-04-04 |
United States Patent
Application |
20130084174 |
Kind Code |
A1 |
Maalouf; Fadi S. ; et
al. |
April 4, 2013 |
STRUT RODS FOR STRUCTURAL GUIDE VANES
Abstract
A reinforced structural guide vane system includes an outer
casing; a center body within the outer casing; a plurality of
structural guide vanes extending between and connected to the
center body and the outer casing; and a plurality of strut rods
extended between and connected to the outer casing and to the
center body.
Inventors: |
Maalouf; Fadi S.; (East
Hampton, CT) ; DiTomasso; John C.; (Glastonbury,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Maalouf; Fadi S.
DiTomasso; John C. |
East Hampton
Glastonbury |
CT
CT |
US
US |
|
|
Assignee: |
UNITED TECHNOLOGIES
CORPORATION
Hartford
CT
|
Family ID: |
46888927 |
Appl. No.: |
13/251502 |
Filed: |
October 3, 2011 |
Current U.S.
Class: |
415/208.1 |
Current CPC
Class: |
Y02T 50/672 20130101;
F02C 7/20 20130101; F01D 25/246 20130101; F01D 25/28 20130101; Y02T
50/60 20130101; F02K 3/06 20130101 |
Class at
Publication: |
415/208.1 |
International
Class: |
F01D 25/00 20060101
F01D025/00 |
Claims
1. A reinforced structural guide vane system comprising: an outer
casing; a center body within the outer casing; a plurality of
structural guide vanes extending between and connected to the
center body and the outer casing; and a plurality of strut rods
extending between and connected to the outer casing and to the
center body.
2. The reinforced structural guide vane system of claim 1, wherein
outer ends of the plurality of structural guide vanes are connected
to the outer casing at locations close to where outer ends of the
plurality of strut rods are connected to the outer casing.
3. The reinforced structural guide vane system of claim 1, wherein
the plurality of structural guide vanes are swept.
4. The reinforced structural guide vane system of claim 3, wherein
the plurality of structural guide vanes are swept back from the
center body to the outer casing.
5. The reinforced structural guide vane system of claim 1, wherein
the plurality of structural guide vanes connect to the plurality of
strut rods at the outer casing.
6. The reinforced structural guide vane system of claim 1, wherein
the system comprises four strut rods.
7. The reinforced structural guide vane system of claim 1, wherein
the plurality of strut rods connect to the center body to form an
H-frame.
8. The reinforced structural guide vane system of claim 7, wherein
the plurality of strut rods connect to the center body
tangentially.
9. The reinforced structural guide vane system of claim 1, wherein
the plurality of strut rods form a plurality of A-frames.
10. The reinforced structural guide vane system of claim 9, wherein
the plurality of strut rods form two or three A-frames.
11. The reinforced structural guide vane system of claim 1, wherein
the outer casing is a fan case.
12. A fan exit case comprising: an outer casing; a center body; a
plurality of structural guide vanes extending between and connected
to the outer casing and the center body; and a plurality of strut
rods extending between and connected to the outer casing and to the
center body, wherein the connections of the plurality of strut rods
and plurality of structural guide vanes are closer together at the
outer casing than at the center body.
13. The fan exit case of claim 11, wherein the plurality of strut
rods are connected to the outer casing and to the center body at
respective positions to form a plurality of A-frame structures.
14. The fan exit case of claim 11, wherein the plurality of strut
rods are connected to the outer casing and to the center body at
respective positions to form an H-frame structure.
15. The fan exit case of claim 13, wherein the plurality of strut
rods are connected to the center body tangentially.
16. The fan exit case of claim 11, wherein the plurality of strut
rods are connected to the outer casing and to the center body with
bolts.
17. The fan exit case of claim 11, wherein the plurality of
structural guide vanes are swept.
18. The fan exit case of claim 17, wherein the plurality of
structural guide vanes are swept back from the center body to the
outer casing.
Description
BACKGROUND
[0001] Gas turbine engines (or combustion turbines) are built
around a center body, holding a power core made up of a compressor,
combustor and turbine, arranged in flow series with an upstream
inlet and downstream exhaust. The compressor compresses air from
the inlet, which is mixed with fuel in the combustor and ignited to
generate hot combustion gas. The turbine extracts energy from the
expanding combustion gas, and drives the compressor via a common
shaft. Energy is delivered in the form of rotational energy in the
shaft, reactive thrust from the exhaust, or both.
[0002] A fan section pulls air into the engine, and is surrounded
by an outer fan casing which defines an air flow path. The outer
casing must be structurally connected to the center body. This
connection can be made with aerodynamic vanes that are called
structural guide vanes because they provide the structural
connection between the outer casing and the center body. These
structural guide vanes can turn and straighten swirling air after
it passes through the fan rotor.
[0003] Turbofan engines are commonly divided into high and low
bypass configurations. High bypass turbofans generate thrust
primarily from the fan, which drives airflow through a bypass duct
oriented around the engine core. This design is common on
commercial aircraft and military transports, where noise and fuel
efficiency are primary concerns. Low bypass turbofans generate
proportionally more thrust from the exhaust flow, providing greater
specific thrust for use on supersonic fighters and other
high-performance aircraft. Unducted (open rotor) turbofans and
ducted turboprop configurations are also known, as are a variety of
counter-rotating and aft-mounted designs.
[0004] Turbofan engine performance depends on precise control of
the working fluid flow. Because engine noise is a factor, however,
particularly for aviation applications, there are competing
engineering challenges for both fan and compressor design.
SUMMARY
[0005] A reinforced structural guide vane system includes an outer
casing; a center body within the outer casing; a plurality of
structural guide vanes extending between and connected to the
center body and the outer casing; and a plurality of strut rods
extending between and connected to the outer casing and to the
center body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a cross-sectional view of a gas turbine engine
with strut rods according to the current invention.
[0007] FIG. 2A is a perspective view of structural members of a fan
exit case with structural guide vanes and strut rods from a front
side.
[0008] FIG. 2B is a view of FIG. 2A with the structural guide vanes
removed.
[0009] FIG. 3 is a perspective view of a back side of a second
embodiment of a fan exit case with structural guide vanes and strut
rods.
[0010] FIG. 4 is a perspective view of a back side of a third
embodiment of a fan exit case with structural guide vanes and strut
rods.
DETAILED DESCRIPTION
[0011] FIG. 1 is a cross-sectional view of gas turbine engine 10,
which includes turbofan 12, compressor section 14, combustion
section 16 and turbine section 18. Compressor section 14 includes
low-pressure compressor 20 and high-pressure compressor 22. Engine
10 also includes bypass section 26 with structural guide vanes 28
and strut rods 30 extending between outer casing 32 and center body
34. Center body 34 houses compressor section 14, combustion section
16 and turbine section 18.
[0012] Air is taken in through fan 12 as fan 12 spins. A portion of
the inlet air is directed to compressor section 14 where it is
compressed by a series of rotating blades and stationary vanes. The
compressed air is mixed with fuel, and then ignited in combustor
section 16. The combustion exhaust is directed to turbine section
18. Blades and vanes in turbine section 18 extract kinetic energy
from the exhaust to turn inner (low spool) shaft 24A, which drives
low pressure compressor 20 and turbofan 12, and outer shaft 24B
which drives high pressure compressor 22.
[0013] The portion of inlet air that is taken in through fan 12 and
not directed through compressor section 14 is bypass air. When fan
12 spins, it creates pressure and imparts swirl into the air. Guide
vanes 28 act to slow down and straighten the air, increasing static
pressure and creating thrust.
[0014] FIG. 2A is a front perspective view of structural members of
fan exit case C with structural guide vanes 28 and strut rods 30.
FIG. 2B is a view similar to FIG. 2A, but with the structural guide
vanes 28 removed. FIGS. 2A and 2B show outer casing 32, structural
guide vanes 28 (with inner ends 36 and outer ends 38), strut rods
30 (with inner ends 40 and outer ends 42) and portions of center
body 34. Vanes 28 can be made of a high strength material, such as
aluminum (including aluminum alloys), a carbon epoxy composite or
different materials depending on system requirements. Rods 30 can
be made of a high-strength, low weight material, such as titanium
or aluminum (including alloys).
[0015] Structural guide vanes 28 are connected to center body 34 at
inner ends 36 and to outer casing 32 at outer ends 38. This
connection can be through bolts or any other connection means to
secure them on inner ends 36 and outer ends 38. Structural guide
vanes 28 are swept back so that they are connected at inner ends 36
to center body 34 at a location closer to fan 12 than the
connection to outer casing 32 at outer ends 38. Strut rods 30 are
connected to center body 34 at inner ends 40 and to outer casing 32
at outer ends 42. These connections can be by bolts or another
method known in the art.
[0016] In FIGS. 2A and 2B, rods 30 are connected in an A-frame
arrangement so that outer ends 42 of two rods 30 connect to outer
casing 32 at a point close together. This point is also at or near
where structural guide vanes 28 are connected to outer casing 32 at
outer ends 38. This embodiment contains three A-frame arrangements
of strut rods 30, but different systems can have more or fewer
A-frames depending on system requirements. Strut rods 30 can be
aerodynamically shaped, for example, with a teardrop shaped cross
section.
[0017] Structural guide vanes 28 are very thin, making them
lightweight but susceptible to torsional winds and stresses from
swirling fan air. Additionally, structural guide vanes 28 are
susceptible to other catastrophic load conditions in an engine,
such as the loss of a fan blade which may directly impact
structural guide vanes 28 and/or may cause severe vibrations within
the engine. By connecting outer ends 42 of strut rods 30 at
locations close to outer ends 38 of guide vanes 28, strut rods 30
reinforce structural guide vanes 28, adding torsional stability and
torsional rigidity for structural guide vanes 28. The insertion,
placement and angles of strut rods 30 allows structural guide vanes
28 to withstand normal loading as well as many catastrophic loading
conditions.
[0018] Additionally, the use of strut rods 30 allows for the
placement of structural guide vanes 28 close to the fan to
efficiently straighten air. Pressure pulsations arriving from
rotation of upstream fan blades generate noise when they encounter
structural guide vanes 28. The smaller the distance between fan
blades and structural guide vanes 28, the louder the noise
generated. This noise must be kept to a minimum, so sweeping
structural guide vanes 28 reduces noise while allowing placement
close to the fan. The sweep angle in structural guide vanes 28
combined with the placement and angle of strut rods 30 provide a
wide base to distribute vertical loads and prevent bending loads in
structural guide vanes 28 while allowing placement toward the front
of the center body 34.
[0019] FIG. 3 is a perspective view of a back side of a second
embodiment of fan exit case C'. FIG. 4 is a perspective view of a
back side of a third embodiment of fan exit case C''. FIGS. 3 and 4
include outer casing 32, guide vanes 28 (with inner ends 36 and
outer ends 38), strut rods 30 (with inner ends 40 and outer ends
42), and center body 34. Structural guide vanes 28 are connected to
center body 34 and to outer casing 32 and are swept back. Strut
rods 30 are connected to center body 34 and to outer casing 32.
[0020] In these embodiments, rods 30 are connected in H-frame
arrangements, forming a sort of "H" around center body 34. In FIG.
3, rods 30 are connected roughly vertically from side portions of
center body 34 (not radially) to outer casing 32. In FIG. 4, rods
30 are connected tangentially to center body 34. Each of these
arrangements connects strut rods 30 outer ends 42 at locations
close to the connection of outer ends 38 of structural guide vanes
28. This allows strut rods 30 to add stability and torsional
strength to structural guide vanes 28. It also allows structural
guide vanes 28 to be swept back and still able to withstand engine
loads while minimizing noise.
[0021] In summary, strut rods 30 are added to fan exit casing C,
C', or C'' to reinforce structural guide vanes 28, bringing
additional torsional stability and torsional rigidity to vanes 28.
Strut rods 30 connect at outer ends 42 to outer casing 32 at
locations close to outer end 38 connections of structural guide
vanes 28 to outer casing 32. This allows structural guide vanes 28
to stay thin and light weight while ensuring they are strong enough
to endure engine loads, including normal loads from airflow from a
fan or loads from catastrophic events such as a fan blade loss.
Strut rods 30 are connected to center body 34 and to outer casing
32 at specific positions to reinforce structural guide vanes 28,
allowing structural guide vanes 28 to be swept back, keeping the
center body 34 connection near the fan while minimizing noise
generated from a close connection.
[0022] While the placement of structural guide vanes and strut rods
has been shown in three embodiments (A-frame and two variations of
H-frames), strut rods can be placed in different positions and at
different angles to reinforce and add torsional stability and
torsional rigidty to the structural guide vanes. The only
requirement is that they are not extending out radially from the
center body to ensure that they can take torsional loads. While the
invention has been shown with individual structural guide vanes,
the structural guide vanes can be arranged in multipacks, with two
or more vanes made integral to each other.
[0023] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment(s) disclosed, but that the invention will
include all embodiments falling within the scope of the appended
claims.
* * * * *