U.S. patent application number 14/881193 was filed with the patent office on 2016-03-31 for fuel nozzle.
The applicant listed for this patent is General Electric Company. Invention is credited to Thomas Edward Johnson, Stephen Gerard Pope, Christopher Michael Prue.
Application Number | 20160091201 14/881193 |
Document ID | / |
Family ID | 48143563 |
Filed Date | 2016-03-31 |
United States Patent
Application |
20160091201 |
Kind Code |
A1 |
Prue; Christopher Michael ;
et al. |
March 31, 2016 |
FUEL NOZZLE
Abstract
A fuel nozzle includes a center body and a shroud
circumferentially surrounding at least a portion of the center body
to define an annular passage between the center body and the
shroud. A plurality of vanes extend radially between the center
body and the shroud in the annular passage. A first ceramic
extension extends downstream from the shroud to define at least a
portion of the annular passage downstream from the shroud.
Inventors: |
Prue; Christopher Michael;
(Greenville, SC) ; Johnson; Thomas Edward; (Greer,
SC) ; Pope; Stephen Gerard; (Roebuck, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
48143563 |
Appl. No.: |
14/881193 |
Filed: |
October 13, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13459483 |
Apr 30, 2012 |
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14881193 |
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Current U.S.
Class: |
239/403 ;
431/354 |
Current CPC
Class: |
F23R 3/28 20130101; F23D
11/406 20130101; F23D 11/383 20130101; F23R 3/286 20130101 |
International
Class: |
F23D 11/38 20060101
F23D011/38; F23D 11/40 20060101 F23D011/40; F23R 3/28 20060101
F23R003/28 |
Claims
1. A fuel nozzle, comprising: a. a center body; b. a shroud
circumferentially surrounding at least a portion of the center body
to define an annular passage between the center body and the
shroud; c. a plurality of vanes that extend radially between the
center body and the shroud in the annular passage; and d. a second
ceramic extension extending downstream from and connected to the
center body.
2. The fuel nozzle as in claim 1, further comprising a brazed
connection between the second ceramic extension and the center
body, wherein the brazed connection is shielded from the annular
passage.
3. The fuel nozzle as in claim 2, further comprising a
substantially flat surface formed by the center body, the second
ceramic extension and the brazed connection inside the annular
passage.
4. The fuel nozzle as in claim 1, further comprising a first
ceramic extension extending downstream from the shroud, wherein the
first ceramic extension and the second ceramic extension further
define the annular passage downstream from the shroud and the
center body, wherein a connector extends between and connects the
shroud and the first ceramic extension.
5. The fuel nozzle as in claim 4, wherein the connector includes a
radius between the shroud and the first ceramic extension.
6. The fuel nozzle as in claim 4, further comprising a
substantially flat surface formed by the shroud, the first ceramic
extension and the connector inside the annular passage.
7. The fuel nozzle as in claim 4, further comprising a
substantially flat surface formed by the shroud, the first ceramic
extension and the connector outside of the annular passage.
8. The fuel nozzle as in claim 4, further comprising a braze
material between the first ceramic extension and the connector,
wherein the braze material is shielded from the annular
passage.
9. The fuel nozzle as in claim 4, further comprising a braze
material between the shroud and the connector, wherein the braze
material is shielded from the annular passage.
10. A fuel nozzle, comprising: a. a center body; b. a shroud
circumferentially surrounding at least a portion of the center body
to define an annular passage between the center body and the
shroud; c. a plurality of vanes that extend radially between the
center body and the shroud in the annular passage; d. a first
ceramic extension extending downstream from the shroud to define at
least a portion of the annular passage downstream from the shroud;
e. a brazed connection between the first ceramic extension and the
shroud; and f. a second ceramic extension extending downstream from
the center body, wherein the second ceramic extension is connected
to the center body, wherein the first ceramic extension and the
second ceramic extension further define the annular passage
downstream from the shroud and the center body.
11. The fuel nozzle as in claim 10, further comprising a
substantially flat surface formed by the shroud, the first ceramic
extension and the brazed connection inside the annular passage.
12. The fuel nozzle as in claim 10, further comprising a brazed
connection between the first ceramic extension and the shroud,
wherein the brazed connection is shielded from the annular
passage.
13. The fuel nozzle as in claim 10, wherein a connector extends
between and connects the shroud and the first ceramic
extension.
14. The fuel nozzle as in claim 13, wherein the connector includes
a radius between the shroud and the first ceramic extension.
15. The fuel nozzle as in claim 13, further comprising a braze
material between the first ceramic extension and the connector,
wherein the braze material is shielded from the annular
passage.
16. The fuel nozzle as in claim 10, further comprising a
substantially flat surface formed by the center body, the second
ceramic extension and the brazed connection inside the annular
passage.
17. The fuel nozzle as in claim 10, further comprising a brazed
connection between the second ceramic extension and the center
body, wherein the brazed connection is shielded from the annular
passage.
18. The fuel nozzle as in claim 10, wherein a connector extends
between and connects the center body and the second ceramic
extension.
19. The fuel nozzle as in claim 18, wherein the connector includes
a radius between the center body and the second ceramic
extension.
20. The fuel nozzle as in claim 18, further comprising a braze
material between the center body and the connector, wherein the
braze material is shielded from the annular passage.
Description
RELATED APPLICATIONS
[0001] The present application is a divisional application of U.S.
application Ser. No. 13/459,483, filed on Apr. 30, 2012, which is
incorporated herein by reference in its entirety and for all
purposes. Any disclaimer that may have occurred during prosecution
of the above-referenced application is hereby expressly
rescinded.
FIELD OF THE INVENTION
[0002] The present invention generally involves a fuel nozzle, such
as may be incorporated into, for example, a combustor.
BACKGROUND OF THE INVENTION
[0003] Combustors are known in the art for igniting fuel with air
to produce combustion gases having a high temperature and pressure.
For example, gas turbine systems, aircraft engines, and numerous
other combustion-based systems include one or more combustors that
mix a working fluid, such as air, with fuel and ignite the mixture
to produce high temperature and pressure combustion gases. Each
combustor generally includes one or more fuel nozzles that mix the
working fluid with the fuel prior to combustion.
[0004] During normal combustor operations, a combustion flame
exists downstream from the fuel nozzles, typically in a combustion
chamber at the exit of the fuel nozzles. It is widely known that
the thermodynamic efficiency of a combustion-based system generally
increases as the operating temperature, namely the combustion gas
temperature, increases. At higher combustion gas temperatures,
however, an event referred to as "flame holding" may occur in which
the combustion flame migrates upstream from the combustion chamber
inside the fuel nozzles. For example, conditions may exist in which
the combustion flame migrates upstream near a fuel port in the fuel
nozzles or near an area of low flow in the fuel nozzles. The fuel
nozzles are typically not designed to withstand the high
temperatures created by flame holding, and flame holding may
therefore cause undesirable wear to a fuel nozzle in a relatively
short amount of time. Once worn, the combustor must be shut down to
allow for partial or full repair/replacement of the fuel nozzle,
resulting in unplanned and/or prolonged outages.
[0005] Various methods are known in the art for preventing or
reducing the occurrence of flame holding. For example, flame
holding is more likely to occur during the use of higher reactivity
fuels or during the use of higher fuel-to-working-fluid ratios.
Flame holding is also more likely to occur during operations in
which the fuel-working fluid mixture flows through the fuel nozzles
at lower velocities. Combustors may therefore be designed with
specific safety margins for fuel reactivity, fuel-to-working-fluid
ratios, and/or fuel-working fluid mixture velocities to prevent or
reduce the occurrence of flame holding. While the safety margins
are effective at preventing or reducing the occurrence of flame
holding, they may also result in reduced operating limits,
additional maintenance, reduced operating lifetimes, and/or reduced
overall thermodynamic efficiency. Therefore, a fuel nozzle that may
be more resistant to the effects of flame holding would be
desirable.
BRIEF DESCRIPTION OF THE INVENTION
[0006] Aspects and advantages of the invention are set forth below
in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0007] One embodiment of the present invention is a fuel nozzle
that includes a center body and a shroud circumferentially
surrounding at least a portion of the center body to define an
annular passage between the center body and the shroud. A plurality
of vanes extend radially between the center body and the shroud in
the annular passage. A first ceramic extension extends downstream
from the shroud to define at least a portion of the annular passage
downstream from the shroud.
[0008] Another embodiment of the present invention is a fuel nozzle
that includes a center body and a shroud circumferentially
surrounding at least a portion of the center body to define an
annular passage between the center body and the shroud. A plurality
of vanes extend radially between the center body and the shroud in
the annular passage. A second ceramic extension extends downstream
from the center body.
[0009] In a still further embodiment of the present invention, a
fuel nozzle includes a center body and a shroud circumferentially
surrounding at least a portion of the center body to define an
annular passage between the center body and the shroud. A plurality
of vanes extend radially between the center body and the shroud in
the annular passage. A first ceramic extension extends downstream
from the shroud to define at least a portion of the annular passage
downstream from the shroud. A brazed connection is between the
first ceramic extension and the shroud. A second ceramic extension
extends downstream from the center body.
[0010] Those of ordinary skill in the art will better appreciate
the features and aspects of such embodiments, and others, upon
review of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] A full and enabling disclosure of the present invention,
including the best mode thereof to one skilled in the art, is set
forth more particularly in the remainder of the specification,
including reference to the accompanying figures, in which:
[0012] FIG. 1 is a simplified cross-section of a combustor
according to one embodiment of the present invention;
[0013] FIG. 2 is a side cross-section view of a fuel nozzle
according to one embodiment of the present invention;
[0014] FIG. 3 is an enlarged view of a portion of the fuel nozzle
shown in FIG. 2 according to a first embodiment of the present
invention;
[0015] FIG. 4 is an enlarged view of a portion of the fuel nozzle
shown in FIG. 2 according to a second embodiment of the present
invention; and
[0016] FIG. 5 is an enlarged view of a portion of the fuel nozzle
shown in FIG. 2 according to a third embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Reference will now be made in detail to present embodiments
of the invention, one or more examples of which are illustrated in
the accompanying drawings. The detailed description uses numerical
and letter designations to refer to features in the drawings. Like
or similar designations in the drawings and description have been
used to refer to like or similar parts of the invention. As used
herein, the terms "first", "second", and "third" may be used
interchangeably to distinguish one component from another and are
not intended to signify location or importance of the individual
components. In addition, the terms "upstream" and "downstream"
refer to the relative location of components in a fluid pathway.
For example, component A is upstream from component B if a fluid
flows from component A to component B. Conversely, component B is
downstream from component A if component B receives a fluid flow
from component A.
[0018] Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that modifications and
variations can be made in the present invention without departing
from the scope or spirit thereof. For instance, features
illustrated or described as part of one embodiment may be used on
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0019] Various embodiments of the present invention include a fuel
nozzle for use, for example, in a combustor. The fuel nozzle
generally includes a center body, a shroud that circumferentially
surrounds at least a portion of the center body to define an
annular passage between the center body and the shroud, and a
plurality of vanes that extend radially between the center body and
the shroud in the annular passage. The center body, shroud, vanes,
and annular passage enhance mixing between fuel, diluents, and/or
other additives prior to reaching a combustion chamber downstream
from the fuel nozzle. In particular embodiments, the fuel nozzle
may further include one or more ceramic extensions downstream from
the shroud and/or center body that increase the useful life and/or
strength of the fuel nozzle. The ceramic extensions provide
additional thermal resistance in the event flame holding were to
occur and generally enhance the wear characteristics of the fuel
nozzles during normal operations. Although exemplary embodiments of
the present invention will be described generally in the context of
a combustor incorporated into a gas turbine for purposes of
illustration, one of ordinary skill in the art will readily
appreciate that embodiments of the present invention may be applied
to any combustor and are not limited to a gas turbine combustor
unless specifically recited in the claims.
[0020] FIG. 1 shows a simplified cross-section view of an exemplary
combustor 10, such as would be included in a gas turbine, according
to one embodiment of the present invention. A casing 12 may
surround the combustor 10 to contain a working fluid flowing to the
combustor 10. One or more fuel nozzles 14 may be radially arranged
between an end cap 16 and an end cover 18. A liner 20 downstream
from the fuel nozzles 14 may combine with the end cap 16 to at
least partially surround and/or define a combustion chamber 22
downstream from the fuel nozzles 14.
[0021] A transition piece 24 downstream from the liner 20 connects
the combustion chamber 22 to a turbine inlet 26. An impingement
sleeve 28 with flow holes 30 may surround the transition piece 24
to define an annular passage 32 between the impingement sleeve 28
and the transition piece 24. The compressed working fluid may pass
through the flow holes 30 in the impingement sleeve 28 to flow
through the annular passage 32 and provide convective cooling to
the transition piece 24 and liner 20. When the compressed working
fluid reaches the end cover 18, the compressed working fluid
reverses direction to flow through one or more of the fuel nozzles
14 where it mixes with fuel before igniting in the combustion
chamber 22 to produce combustion gases having a high temperature
and pressure.
[0022] FIG. 2 provides a side cross-section view of the fuel nozzle
14 according to one embodiment of the present invention. As shown
in FIG. 2, the fuel nozzle 14 generally includes a center body 40,
a shroud 42, and a plurality of vanes 44. The center body 40 may be
attached to the end cover 18 and generally extends downstream from
the end cover to define an axial centerline 46 of the fuel nozzle
14. One or more passages in the center body 40 may provide fluid
communication through the center body 40 so that fuel, diluents,
and/or other additives may be supplied through the end cover 18 and
center body 40 to the fuel nozzle 14. For example, as shown in FIG.
2, a plenum 48 in the center body 40 may provide fluid
communication for fuel, diluents, and/or other additives to flow
through end cover 18 and into the fuel nozzle 14.
[0023] The shroud 42 circumferentially surrounds at least a portion
of the center body 40 to define an annular passage 50 between the
center body 40 and the shroud 42, and the vanes 44 may extend
radially between the center body 40 and the shroud 42 in the
annular passage 50. The vanes 44 may include an upstream edge 52
and a downstream edge 54 and may be curved or angled with respect
to the axial centerline 46 to impart tangential velocity or swirl
to fluids flowing through the annular passage 50. For example, in
particular embodiments the vanes 44 may include one or more fuel
ports 56 so that fuel supplied through the plenum 48 may flow out
of the vanes 44 to mix with working fluid flowing through the
annular passage 50. The diameter and angle of the fuel ports 56
combine to ensure that the fuel adequately penetrates into the
annular passage 50 and to prevent the fuel from simply streaming
along the center body 40, the shroud 42, and/or the vanes 44. In
this manner, the fuel and working fluid may mix in the annular
passage 50 before entering the combustion chamber 22 and
combusting.
[0024] Operational experience, testing, and computational fluid
dynamic calculations indicate that the annular passage 50 may
create an environment conducive to flame holding. For example, the
downstream edge 54 of the vanes 44 may produce low flow areas or
flow separation areas conducive to flame holding. As a result,
various embodiments of the present invention may include one or
more ceramic extensions downstream from the shroud 42 and/or center
body 40 to provide increased thermal and/or wear tolerance for the
fuel nozzles 14. The ceramic extensions may be manufactured and/or
machined to conform to the particular diameter and/or thickness of
the shroud 42 and/or center body 40, thereby producing a
substantially flat surface along the fuel nozzle 14. In particular
embodiments, welding, brazing, and/or other mechanical devices may
be used to connect the ceramic extensions to the shroud 42 and/or
center body 40. If welded or brazed, the design of the weld or
braze joint may ensure that the temperature-sensitive portion of
the joint will not be exposed to the higher temperatures that may
exist inside the annular passage 50 to protect the integrity of the
joint. For example, the sensitive portion of the joint may be
located on a surface of the ceramic extension, shroud 42, and/or
center body 40 that is not exposed to the higher temperatures
associated with the annular passage 50.
[0025] In the particular embodiment shown in FIG. 2, the fuel
nozzle 14 includes a first ceramic extension 60 that extends
downstream from the shroud 42 and a second ceramic extension 62
that extends downstream from the center body 40. The first ceramic
extension 60 may have a similar size and shape as the shroud 42 and
at least partially define the annular passage 50 downstream from
the shroud 42. Similarly, the second ceramic extension 62 may
conform in size and shape to the center body 40 and may include the
plenum 48 defined therein to provide fluid communication through
the second ceramic extension 62. The ceramic extensions 60, 62 may
connect to the respective shroud 42 and/or center body 40 proximate
to the downstream edge 54 of the vanes 44. In this manner, the
ceramic extensions 60, 62 may provide the desired thermal
characteristics in the fuel nozzle 14 at a location that may be
susceptible to flame holding. However, one of ordinary skill in the
art will readily appreciate from the teachings herein that
embodiments of the present invention are not limited to a
particular connection point for the ceramic extensions 60, 62
unless specifically recited in the claims.
[0026] FIG. 3 provides an enlarged view of a portion of the fuel
nozzle 14 shown in FIG. 2 to more clearly illustrate the
connections with the ceramic extensions 60, 62 according to a first
embodiment of the present invention. As shown, the fuel nozzle 14
may include a connector 70 that joins the ceramic extensions 60, 62
to the respective shroud 42 and/or center body 40. The connector 70
may include a threaded engagement or other mechanical device for
attaching or joining the ceramic extensions 60, 62 to the
respective shroud 42 and/or center body 40. Alternately, as shown
in FIG. 3, the connector 70 may be manufactured from a suitable
alloy that allows the ceramic extensions 60, 62 to be welded or
brazed to the respective metallic shroud 42 and/or center body 40.
For example, the connector 70 may include an alloy of iron, nickel,
and cobalt to provide a suitable transition piece for welding or
brazing the ceramic extensions 60, 62 to the respective shroud 42
and/or center body 40. Suitable braze materials 72 may include, for
example, palladium, aluminum-silicon, copper, copper-silver, brass,
and/or nickel alloys. To protect the integrity of the brazed
connection between the ceramic extensions 60, 62 and the respective
shroud 42 and/or center body 40, the connector 70 may be designed
to allow the shroud 42, center body 40, and/or connector 70 to
shield the braze material 72 from the temperatures associated with
the annular passage 50. For example, as shown in the particular
embodiment illustrated in FIG. 3, the braze material 72 between the
shroud 42 and the connector 70 is not exposed to the annular
passage 50, shielding the braze material 72 from the higher
temperatures associated with the annular passage 50.
[0027] In the particular embodiment shown in FIG. 3, the connector
70 for the first ceramic extension 60 includes a radius 74. The
radius 74 adapts the diameter of the first ceramic extension 60 to
fit the shroud 42 having a slightly different diameter. As a
result, the radius 74 of the less expensive connector 70 may be
more easily adjusted as needed to allow the same ceramic extension
60 to fit multiple fuel nozzle 14 sizes. In contrast, the connector
70 for the second ceramic extension 62 does not include the radius
74. Instead, the connector 70 for the second ceramic extension 62
in the particular embodiment shown in FIG. 3 is generally straight
and forms a full lap joint with both the second ceramic extension
62 and the center body 40, allowing the second ceramic extension 62
to abut the center body 40. As a result, the brazed connection
between the second ceramic extension 62 and the center body 40
creates a substantially flat surface 76 inside the plenum 48 to
reduce resistance to fluid flow inside the plenum 76.
[0028] FIGS. 4 and 5 provide an enlarged views of a portion of the
fuel nozzle 14 shown in FIG. 2 according to still further
embodiments of the present invention. As shown in FIG. 4, the
connector 70 for the first ceramic extension 60 forms a half-lap
joint with both the first ceramic extension 60 and the shroud 42.
As a result, the brazed connection between the first ceramic
extension 60 and the shroud 42 creates a substantially flat surface
76 both inside and outside of the annular passage 50. In addition,
the half-lap joints allow the first ceramic extension 60, shroud
42, and/or connector 70 to shield the braze material 72 from the
temperatures associated with the annular passage 50 to protect the
integrity of the brazed connection. In the particular embodiment
shown in FIG. 5, the connectors 70 for the first and second ceramic
extensions 60, 62 are T-shaped and located primarily outside of the
annular passage 50. In this manner, the brazed connections provide
substantially flat surfaces inside the annular passage 50 while
also enhancing protection of the braze material 72 from the high
temperatures associated with the annular passage 50. One of
ordinary skill in the art will readily appreciate that many
possible design combinations exist for the connectors 70, and the
various embodiments of the present invention are not limited to any
particular design or location for the connectors 70 unless
specifically recited in the claims.
[0029] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *