U.S. patent application number 11/406892 was filed with the patent office on 2007-05-24 for method and apparatus for increasing a durability of a body.
This patent application is currently assigned to General Electric Company. Invention is credited to Douglas M. Carper, Michael L. Millard.
Application Number | 20070117480 11/406892 |
Document ID | / |
Family ID | 34435568 |
Filed Date | 2007-05-24 |
United States Patent
Application |
20070117480 |
Kind Code |
A1 |
Carper; Douglas M. ; et
al. |
May 24, 2007 |
Method and apparatus for increasing a durability of a body
Abstract
An inseparable assembly includes a body including a ceramic
matrix composite material, and a cover including a metallic wire
mesh. The cover is bonded to the body so that the cover overlaps at
least a portion of the body.
Inventors: |
Carper; Douglas M.;
(Cincinnati, OH) ; Millard; Michael L.;
(Cincinnati, OH) |
Correspondence
Address: |
DAVID E. CRAWFORD, JR.;SONNENSCHEIN NATH & ROSENTHAL
P.O BOX 061080
WACKER DRIVE STATION, SEARS TOWER
CHICAGO
IL
60606-1080
US
|
Assignee: |
General Electric Company
|
Family ID: |
34435568 |
Appl. No.: |
11/406892 |
Filed: |
April 19, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10703273 |
Nov 7, 2003 |
|
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11406892 |
Apr 19, 2006 |
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Current U.S.
Class: |
442/6 ;
239/265.39; 442/10; 442/11; 442/12; 442/13; 442/14; 442/15; 442/16;
442/17; 442/18; 442/19; 442/43; 442/7; 442/8; 442/9 |
Current CPC
Class: |
Y10T 442/109 20150401;
Y10T 442/11 20150401; Y10T 442/114 20150401; F02K 1/12 20130101;
F02K 1/805 20130101; Y10T 442/172 20150401; F05D 2240/55 20130101;
Y02T 50/60 20130101; Y10T 442/122 20150401; Y10T 442/126 20150401;
Y10T 442/121 20150401; Y10T 442/129 20150401; Y10T 442/119
20150401; Y10T 442/131 20150401; Y10T 442/117 20150401; Y10T
442/112 20150401; Y10T 442/124 20150401; Y10T 442/116 20150401;
Y10T 442/128 20150401 |
Class at
Publication: |
442/006 ;
442/007; 442/008; 442/009; 442/010; 442/011; 442/012; 442/013;
442/014; 442/015; 442/016; 442/017; 442/018; 442/019; 442/043;
239/265.39 |
International
Class: |
D03D 15/00 20060101
D03D015/00 |
Claims
1-9. (canceled)
10. A variable geometry exhaust nozzle for a gas turbine engine
having an exhaust centerline, said nozzle comprising: a plurality
of flaps arranged around the exhaust centerline, each of said flaps
having a sealing surface; and a plurality of flap seals, each of
said seals having a body including a sealing surface and being
positioned between a pair of flaps of said plurality of flaps such
that said sealing surface of said seal engages said sealing surface
of at least one of said adjacent flaps, wherein at least one of
said seals has a cover including a metallic wire mesh bonded to
said body with an adhesive so that said cover overlaps at least a
portion of an edge of said body.
11. A variable geometry exhaust nozzle in accordance with claim 10
wherein said seal body comprises an oxide-based ceramic matrix
composite material.
12. A variable geometry exhaust nozzle in accordance with claim 11
wherein said adhesive comprises a ceramic adhesive.
13. A variable geometry exhaust nozzle in accordance with claim 12
wherein said ceramic adhesive comprises the combination of a glass
powder, an alumina powder, and a silica yielding polymer.
14. A variable geometry exhaust nozzle in accordance with claim 10
wherein said metallic wire mesh comprises at least one of a
nickel-based alloy, a cobalt-based alloy, and a stainless
steel.
15. A method for increasing a durability of a body comprising a
ceramic matrix composite material, said method comprising the steps
of: positioning a cover comprising a metallic wire mesh over at
least a portion of said body; and bonding said positioned cover to
said body.
16. A method in accordance with claim 15 wherein said body further
comprises a first surface, a second surface, and an edge extending
between said first surface and said second surface, said
positioning step comprising positioning said cover over at least a
portion of said edge.
17. A method in accordance with claim 16 further comprising
machining at least one of said first surface and said second
surface prior to positioning said cover.
18. A method in accordance with claim 15 further comprising the
step of forming said cover such that at least a portion of said
cover has a shape corresponding to at least a portion of said
body.
19. A method in accordance with claim 15 wherein said cover is
bonded to said body using a ceramic adhesive.
20. A method in accordance with claim 15 further comprising the
step of cleaning said body to provide a substantially wetable
surface prior to bonding said cover to said body.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to ceramic matrix
composite materials, and more specifically to a method and
apparatus for increasing a durability of a ceramic matrix composite
material.
[0002] Gas turbine engines typically include a compressor, a
combustor, and a turbine. Airflow entering the compressor is
compressed and channeled to the combustor, wherein the air is mixed
with a fuel and ignited within a combustion chamber to produce
combustion gases. The combustion gases are channeled to a turbine
that extracts energy from the combustion gases for powering the
compressor. One turbine extracts energy from the combustion gases
to power the compressor. Other turbines may be used to power an
output shaft connected to a load, such as an electrical generator.
In some applications, the combustion gases exiting the turbine(s)
are channeled through an engine exhaust nozzle to produce thrust
for propelling an aircraft in flight.
[0003] Some known gas turbine aircraft engines include an engine
exhaust nozzle having a variable geometry configuration, wherein a
cross-sectional area of the exhaust nozzle is adjustable. Variable
geometry exhaust nozzles typically have a plurality of flaps and a
plurality of seals mounted circumferentially about a centerline of
the exhaust nozzle. The seals are mounted generally between
adjacent nozzle flaps, such that the flaps and seals form a
generally continuous interior surface that directs a flow of the
combustion gases through the exhaust nozzle. As their name implies,
the seals seal the spaces between the flaps and shield various
components of the exhaust nozzle from high temperatures and high
thermal gradients during flow of the combustion gases therein.
[0004] To facilitate extending a useful life at high temperature
operation, some seals are fabricated from non-metallic composite
materials, such as ceramic matrix composite materials. However,
even such non-metallic materials experience wear and other damage
due to the hostile operating environment in gas turbine engines.
For example, the seal edges may erode due to frictional contact
with the flaps as well as point contact rub caused by part
deformation from the high thermal gradients the seals experience
during operation.
SUMMARY OF THE INVENTION
[0005] In one aspect, an inseparable assembly is provided having a
body including a ceramic matrix composite material, and a cover
including a metallic wire mesh. The cover is bonded to the body so
that the cover overlaps at least a portion of the body.
[0006] In another aspect, a variable geometry exhaust nozzle is
provided for a gas turbine engine having an exhaust centerline. The
nozzle includes a plurality of flaps arranged around the exhaust
centerline, each of the flaps having a sealing surface, and a
plurality of flap seals. Each seal has a body which includes a
sealing surface. The body is positioned between a pair of flaps of
the plurality of flaps so that the sealing surface of the seal
engages the sealing surface of at least one of the adjacent flaps.
At least one of the seals has a cover including a metallic wire
mesh bonded to the body with an adhesive so that the cover overlaps
at least a portion of an edge of the body.
[0007] In yet another aspect, a method is provided for increasing a
durability of a body including a ceramic matrix composite material.
The method includes the steps of positioning a cover including a
metallic wire mesh over at least a portion of the body, and bonding
the positioned cover to the body.
[0008] Other features of the present invention will be in part
apparent and in part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic of an exemplary gas turbine
engine;
[0010] FIG. 2 is a perspective of a portion of the gas turbine
engine shown in FIG. 1 illustrating a portion of an exemplary
exhaust nozzle assembly;
[0011] FIG. 3 is a cross section of the exhaust nozzle assembly
shown in FIG. 2 taken alone line 3-3 of FIG. 2;
[0012] FIG. 4 is a perspective of an exemplary flap seal body for
use with the exhaust nozzle assembly shown in FIG. 2;
[0013] FIG. 5 is a perspective of the flap seal body shown in FIG.
4 after a material removal process;
[0014] FIG. 6 is a cross-section of the flap seal body shown in
FIG. 5 taken along line 6-6 of FIG. 5;
[0015] FIG. 7 is a cross-section of the flap seal body shown in
FIG. 5 taken along line 7-7 of FIG. 5;
[0016] FIG. 8 is a perspective of an exemplary cover for use with
the flap seal body shown in FIG. 5;
[0017] FIG. 9 is a cross-section of the cover shown in FIG. 8 taken
along line 9-9 of FIG. 8; and
[0018] FIG. 10 is a perspective view of the flap seal body shown in
FIG. 5 having a plurality of covers, such as the cover shown in
FIG. 8, bonded thereto.
[0019] Corresponding reference characters indicate corresponding
parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] Referring now the to the drawings, FIG. 1 is a schematic of
a gas turbine engine 20 including a fan 22, a high pressure
compressor 24, and a combustor 26. The engine 20 also includes a
high pressure turbine 28 and a low pressure turbine 30. The fan 22
and the turbine 30 are coupled by a first shaft 34, and the high
pressure compressor 24 and the turbine 28 are coupled by a second
shaft 36. In one embodiment, the engine 20 is a F414 engine
commercially available from GE Aircraft Engines, Evendale,
Ohio.
[0021] In operation, air received through an inlet end 38 of the
engine 20 is compressed by the fan 22 and channeled to the high
pressure compressor 24, wherein the compressed air is compressed
even further. The highly compressed air from the high pressure
compressor 22 is channeled to the combustor 26, wherein it is mixed
with a fuel and ignited to produce combustion gases. The combustion
gases are channeled from the combustor 26 to drive the turbines 28
and 30, and exit an outlet end 40 of the engine 20 through an
exhaust nozzle assembly 42 to provide thrust.
[0022] FIG. 2 is a perspective of a portion of the gas turbine
engine 20 illustrating a sector of the exhaust nozzle assembly 42.
FIG. 3 is a cross section of the exhaust nozzle assembly 42 taken
along line 3-3 of FIG. 2. The nozzle assembly 42 includes a
plurality of flaps 70 and a plurality of flap seals 72. The flaps
70 and the flap seals 72 are arranged circumferentially around a
centerline 74 of the exhaust nozzle assembly 42. Each flap seal 72
is positioned between a pair of adjacent flaps 70 and radially
inwardly with respect to the flaps 70, such that a portion of each
flap seal 72 overlaps a portion of each adjacent flap 70. More
specifically, each flap 70 includes a body 76 having a sealing
surface 78, and each flap seal 72 includes a body, generally
referred to by the reference numeral 80, having a sealing surface
82. The flap seals 72 overlap adjacent flaps 70 such that during
operation of the engine 20 a portion of each flap sealing surface
78 contacts a portion of each corresponding sealing surface 82
generally along an axial length of the flaps 70 and the flap seals
72. In one embodiment, the flap seal bodies 80 are fabricated from
a ceramic matrix composite material. In another embodiment, the
flap seal bodies 80 are fabricated from an oxide-based ceramic
matrix composite material. Additionally, in one embodiment, the
flap bodies 76 are fabricated from a ceramic matrix composite
material.
[0023] Respective radially inner surfaces 86 and 88 of the flaps 70
and the flap seals 72 form a generally continuous interior surface
defining an exhaust nozzle orifice 90. The orifice 90 directs a
flowpath of gases received from the turbine 30 (shown in FIG. 1)
out of the engine outlet end 40 to produce thrust. In the exemplary
embodiment, the exhaust nozzle assembly 42 is a variable geometry
exhaust nozzle, wherein a cross-sectional area of the nozzle
orifice 90 is adjustable. A mounting assembly, generally referred
to herein with the reference numeral 92, couples each flap seal 72
to adjacent flaps 70. The assembly 92 is movably coupled to an
outer casing 94 of the engine 20 to facilitate adjustment of the
cross-sectional area of the orifice 90. Additionally, the assembly
92 allows relative motion between the flaps 70 and the flap seals
72 to facilitate contact between the sealing surfaces 78 and
respective sealing surfaces 82, and to facilitate adjustment of the
cross-sectional area of the orifice 90. In the exemplary
embodiment, the exhaust nozzle orifice 90 is generally annular,
however, it should be understood the orifice 90 may be any suitable
shape. For example, in an alternative embodiment, the exhaust
nozzle orifice 90 is generally rectangular.
[0024] During operation of the engine 20, a pressure of the
flowpath gases exiting through the exhaust nozzle orifice 90 urges
the flap seals 72 against the flaps 70, and more specifically,
urges the sealing surfaces 82 of the seals 72 in contact with
respective sealing surfaces 78 of the flaps 70. As gases flow
through the nozzle assembly 42, and more specifically the exhaust
nozzle orifice 90, contact between the sealing surfaces 78 and
respective sealing surfaces 82 substantially prevents leakage of
gases between the flaps 70 and the flap seals 72.
[0025] FIG. 4 is a perspective of an exemplary flap seal body 80
for use with the exhaust nozzle assembly 42 (shown in FIG. 2).
Generally, the body 80 includes a plurality of ends 100, 102, 104,
and 106. The body 80 also includes the sealing surface 82, the
radially inner surface 88, and a plurality of other surfaces 120,
122, 124, and 126. Any of the surfaces 82, 88, 120, 122, 124, and
126 may be designated a first surface or a second surface. The body
80 also includes plurality of openings, generally referred to by
the reference numeral 128, for attachment to the mounting assembly
92.
[0026] FIG. 5 is a perspective of the flap seal body 80 after a
material removal process. FIG. 6 is a cross-section of the flap
seal body 80 taken along line 6-6 of FIG. 5. FIG. 7 is a
cross-section of the flap seal body 80 taken along line 7-7 of FIG.
5. Material is removed from the body 80 using any suitable
machining process, such as, for example, cutting, grinding,
planing, facing, and/or milling. After material removal, the body
80 generally includes the ends 100, 102, 104, and 106, the sealing
surface 82, the radially inner surface 88, and a plurality of
mating surfaces 130, 132, 134, 136, 138, 140, 142, 144, 146, 148,
and 150. In the exemplary embodiment, the mating surfaces 130, 134,
138, 140, 142, and 144 are generally perpendicular to the surfaces
132 and 136. In addition, in the exemplary embodiment, the mating
surfaces 132 and 136 are generally perpendicular to the surfaces
146, 148, and 150. Any of the surfaces 82, 88, 130, 132, 134, 136,
138, 140, 142, 144, 146, 148, and 150 may be designated a first
surface or a second surface.
[0027] A plurality of edges 152, 154, 156, 158, 160, 162, 164, 166,
168, 170, 172, and 174 extend between corresponding surfaces 130,
132, 134, 136, 138, 140, 142, 144, 146, 148, and 150 of the body
80. More specifically, the edge 152 is defined at the intersection
of the surfaces 130 and 132, the edge 154 is defined at the
intersection of the surfaces 132 and 134, the edge 156 is defined
at the intersection of the surfaces 134 and 136, and the edge 158
is defined at the intersection of the surfaces 136 and 138.
Similarly, the edge 160 is defined at the intersection of the
surfaces 140 and 132, the edge 162 is defined at the intersection
of the surfaces 132 and 142, the edge 164 is defined at the
intersection of the surfaces 142 and 136, and the edge 166 is
defined at the intersection of the surfaces 136 and 144.
Additionally, the edge 168 is defined at the intersection of the
surfaces 150 and 136, the edge 170 is defined at the intersection
of the surfaces 136 and 148, the edge 172 is defined at the
intersection of the surfaces 148 and 132, and the edge 174 is
defined at the intersection of the surfaces 132 and 146.
[0028] FIG. 8 is a perspective of an exemplary cover, generally
referred to by the reference numeral 180, for use with the flap
seal body 80 (shown in FIG. 5). FIG. 9 is a cross-section of the
cover 180 taken along line 9-9 of FIG. 8. The cover 180 includes a
plurality of outer sides 182, 184, and 186, and a plurality of
mating sides 188, 190, 192, 194, and 196. The cover 180 also
includes end surfaces 198 and 200 generally defining respective
ends, generally referred to by the reference numerals 202 and 204,
of the cover 180. In the exemplary embodiment, the outer sides 182
and 186 are generally perpendicular to the outer side 184, and the
mating sides 188 and 192 are generally perpendicular to the mating
sides 190, 194, and 196. The cover 180 has a predetermined
durability that is greater than a predetermined durability of a
portion of the flap seal body 80 adjacent one or more of the flap
seal body ends 100, 102, 104, and 106. In one embodiment, the flap
seal body 80 has a substantially uniform durability throughout that
is less than the predetermined durability of the cover 180.
[0029] In one embodiment, the cover 180 is a metallic wire mesh,
however, it should be understood that the cover 180 may be any
material, and may be fabricated in any material configuration,
having a durability greater than a predetermined durability of a
portion of the flap seal body 80, and more specifically, a portion
of the flap seal body 80 that includes the cover 180 bonded
thereto, as described below. In one embodiment, the cover 180 is a
metallic wire mesh fabricated from a nickel-based alloy, such as,
for example, HAYNES.RTM. HASTELLOY X.TM. alloy, commercially
available from Haynes International, Inc., Kokomo, Ind. In another
embodiment, the cover 180 is a metallic wire mesh fabricated from a
cobalt-based alloy, such as, for example, HAYNES.RTM. alloy 188,
commercially available from Haynes International, Inc., Kokomo,
Ind. In yet another embodiment, the cover 180 is a metallic wire
mesh fabricated from stainless steel, such as, for example,
stainless steel grade 316 commercially available from Cleveland
Wire Cloth, Cleveland, Ohio.
[0030] FIG. 10 is a perspective view of the flap seal body 80
having a plurality of the covers 180 bonded thereto to increase a
durability of the seal body 80 generally adjacent the ends 102,
104, and 106. In the exemplary embodiment, a plurality of the
covers 180 are bonded to the seal body 80. However, it should be
understood that the seal body 80 may have any number of the covers
180 bonded thereto. For example, in an alternative embodiment, the
body 80 has only one cover 180 bonded thereto. Additionally, in the
exemplary embodiment, the body 80 includes a plurality of the
covers 180 that are each bonded to the seal body 80 adjacent a
corresponding end 102, 104, and 106. However, it should be
understood that the seal body 80 may include a cover 180 bonded
thereto adjacent the body end 100.
[0031] The covers 180, referred to herein as the covers 180a, 180b,
and 180c with regard to FIG. 10, are bonded to the seal body 80
using an adhesive. In one embodiment, the adhesive used to bond the
covers 180a, 180b, and 180c to the seal body 80 is a ceramic
adhesive, for example, a ceramic adhesive produced by combining a
glass powder, for example, SP921.RTM. glass powder from Specialty
Glass, Florida, and an alumina powder with a silica yielding
polymer. Another example of a ceramic adhesive is Cotronics
901.RTM. adhesive, available from Cotronics Corporation, Brooklyn,
N.Y. Additionally, prior to bonding the covers 180a, 180b, and 180c
to the flap seal body 80, the seal body mating surfaces 130, 132,
134, 136, 138, 140, 142, 144, 146, 148, and 150 are cleaned by
slightly sanding the surfaces and applying a solvent, for example
acetone or isopropanol, to provide a substantially wetable surface
that facilitates adhesion between the adhesive and the mating
surfaces.
[0032] After cleaning, the adhesive is applied to some or all of
the mating sides 188, 190, 192, 194, and 196 of each cover 180a,
180b, and 180c, in addition to the seal body mating surfaces 130,
132, 134, 136, 138, 140, 142, 144, 146, 148, and 150. The covers
180a, 180b, and 180c are then positioned on the seal body 80 over
the respective ends 102, 104, and 106, as illustrated in FIG. 10.
More specifically, the cover 180a is positioned over the end 102
such that the mating sides 188, 190, 192, 194, and 196 of the cover
180a contact the respective mating surfaces 132, 148, 136, 150, and
146 of the body 80, and accordingly, the cover 180a overlaps the
seal body edges 168, 170, 172, and 174. Additionally, the cover
180b is positioned over the end 104 such that the mating sides 188,
190, 192, 194, and 196 of the cover 180b contact the respective
mating surfaces 132, 134, 136, 138, and 130 of the body 80, and
accordingly, the cover 180b overlaps the seal body edges 152, 154,
156, and 158. Furthermore, the cover 180c is positioned over the
end 106 such that the mating sides 188, 190, 192, 194, and 196 of
the cover 180c contact the respective mating surfaces 136, 142,
132, 140, and 144 of the body 80, and accordingly, the cover 180c
overlaps the seal body edges 160, 162, 164, and 166. Once dry, the
adhesive bonds the covers 180 to the seal body 80. The greater
durability of the covers 180 with respect to the body 80
facilitates increasing the durability of the seal body ends 102,
104, and 106 by reinforcing the body 80 adjacent the ends 102, 104,
and 106.
[0033] In the exemplary embodiment, the covers 180a, 180b, and 180c
each substantially overlap the respective ends 102, 104, and 106.
However, it will be understood that the covers 180a, 180b, and 180c
may each overlap only a portion of the respective ends 102, 104,
and 106. Additionally, in the exemplary embodiment, the covers
180a, 180b, and 180c each substantially overlap the respective
edges 168, 170, 172, 174, 152, 154, 156, 158, 160, 162, 164, and
166. However, it will be understood that the covers 180a, 180b, and
180c may each overlap only a portion of the respective edges 168,
170, 172, 174, 152, 154, 156, 158, 160, 162, 164, and 166.
[0034] Although the seal body 80 is herein described and
illustrated in the exemplary manner, it should be understood that
the seal body 80 may include any number of covers 180 each bonded
to any portion of the body 80 such that at least one cover 180
overlaps at least a portion of the body 80.
[0035] The above-described cover is cost-effective and reliable for
increasing a durability of a ceramic matrix composite material.
More specifically, the cover facilitates reinforcing a portion of
the ceramic matrix composite material. As a result, the cover may
increase the performance and useful life of the ceramic matrix
composite material, and thereby reduce replacement costs.
Additionally, the cover may increase a wear resistance and a strain
to failure ratio of the ceramic matrix composite material, and may
allow the ceramic matrix composite material to experience higher
thermal gradients without failing. In the exemplary embodiment, the
cover facilitates increasing the performance and useful life of a
gas turbine engine exhaust seal. As a result, the exemplary cover
facilitates reducing a number of exhaust nozzle seals that are
replaced within a gas turbine engine to maintain a desired
operational efficiency of the engine.
[0036] Although the invention is herein described and illustrated
in association with a gas turbine engine, and more specifically, in
association with an exhaust nozzle seal for use with a gas turbine
engine, it should be understood that the present invention is
applicable to any ceramic matrix composite material. Accordingly,
practice of the present invention is not limited to gas turbine
engine exhaust nozzle seals nor gas turbine engines generally.
Additionally, practice of the present invention is not limited to
gas turbine engine exhaust nozzle seals that are fabricated from
ceramic matrix composite materials. Rather, it should be understood
that the present invention is applicable to gas turbine engine
seals that are fabricated from materials other than ceramic matrix
composite materials.
[0037] Exemplary embodiments of gas turbine engine exhaust nozzle
assemblies are described above in detail. The assemblies are not
limited to the specific embodiments described herein, but rather,
components of each assembly may be utilized independently and
separately from other components described herein. Each exhaust
nozzle assembly component can also be used in combination with
other exhaust nozzle assembly components.
[0038] When introducing elements of the present invention or the
preferred embodiment(s) thereof, the articles "a", "an", "the" and
"said" are intended to mean that there are one or more of the
elements. The terms "comprising", "including" and "having" are
intended to be inclusive and mean that there may be additional
elements other than the listed elements.
[0039] As various changes could be made in the above constructions
without departing from the scope of the invention, it is intended
that all matter contained in the above description or shown in the
accompanying drawings shall be interpreted as illustrative and not
in a limiting sense.
* * * * *