U.S. patent application number 13/918437 was filed with the patent office on 2014-12-18 for additively manufactured nozzle tip for fuel injector.
The applicant listed for this patent is Delavan Inc. Invention is credited to Matthew Raymond Donovan.
Application Number | 20140367494 13/918437 |
Document ID | / |
Family ID | 52018388 |
Filed Date | 2014-12-18 |
United States Patent
Application |
20140367494 |
Kind Code |
A1 |
Donovan; Matthew Raymond |
December 18, 2014 |
ADDITIVELY MANUFACTURED NOZZLE TIP FOR FUEL INJECTOR
Abstract
A fuel injector for a gas turbine engine is disclosed that
includes a nozzle tip assembly having a nozzle body substantially
monolithically formed by additive manufacturing and having at least
one fuel circuit defined therein and at least one air circuit
defined therein.
Inventors: |
Donovan; Matthew Raymond;
(Ankeny, IA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Delavan Inc |
West Des Moines |
IA |
US |
|
|
Family ID: |
52018388 |
Appl. No.: |
13/918437 |
Filed: |
June 14, 2013 |
Current U.S.
Class: |
239/400 ;
239/408 |
Current CPC
Class: |
F23D 11/38 20130101;
F23R 3/36 20130101; F23D 11/10 20130101; F23R 3/14 20130101; F23R
2900/00018 20130101; F23R 3/28 20130101 |
Class at
Publication: |
239/400 ;
239/408 |
International
Class: |
F23R 3/36 20060101
F23R003/36 |
Claims
1. A fuel injector for a gas turbine engine comprising: a nozzle
tip assembly including a nozzle body substantially monolithically
formed by additive manufacturing and having at least one fuel
circuit defined therein and at least one air circuit defined
therein.
2. A fuel injector as recited in claim 1, wherein the nozzle body
has an outer fuel circuit for accommodating transfer of a gaseous
fuel and an inner fuel circuit for accommodating transfer of a
liquid fuel.
3. A fuel injector as recited in claim 2, wherein the nozzle body
has an outer air circuit formed between the outer fuel circuit and
the inner fuel circuit.
4. A fuel injector as recited in claim 3, wherein gaseous fuel
transfer ports are defined within the nozzle body that extend
between the outer fuel circuit and the outer air circuit.
5. A fuel injector as recited in claim 3, wherein liquid fuel
transfer ports are defined within the nozzle body that extend
between the inner fuel circuit and the outer air circuit.
6. A fuel injector as recited in claim 3, wherein a plurality of
axial turning vanes are formed within the outer air circuit.
7. A fuel injector as recited in claim 1, wherein the nozzle tip
assembly depends from an end of a feed arm having at least one fuel
passage therein to communicate with the at least one fuel
circuit.
8. A fuel injector as recited in claim 7, wherein the nozzle tip
assembly depends from an end of a feed arm having a first fuel
passage to communicate with the outer fuel circuit of the nozzle
body and a second fuel passage to communicate with the inner fuel
circuit of the nozzle body.
9. A fuel injector as recited in claim 1, wherein the nozzle body
is formed by direct metal laser sintering.
10. A fuel injector as recited in claim 3, wherein a pressure
atomizer is disposed within an inner air circuit of the nozzle
body.
11. A fuel injector for a gas turbine engine comprising: a) a feed
arm having a first and second fuel passages; and b) a nozzle tip
assembly depending from an end of the feed arm, wherein the nozzle
tip assembly includes a nozzle body that is substantially
monolithically formed by additive manufacturing and has a first
fuel circuit formed therein for accommodating transfer of a gaseous
fuel delivered by the first fuel passage of the feed arm and a
second fuel circuit formed therein for accommodating transfer of a
liquid fuel delivered by the second fuel passage of the feed
arm.
12. A fuel injector as recited in claim 11, wherein the nozzle body
includes an outer air circuit formed between the first fuel circuit
and the second fuel circuit.
13. A fuel injector as recited in claim 12, wherein gaseous fuel
transfer ports are defined within the nozzle body that extend
between the outer fuel circuit and the outer air circuit.
14. A fuel injector as recited in claim 12, wherein liquid fuel
transfer ports are defined within the nozzle body that extend
between the inner fuel circuit and the outer air circuit.
15. A fuel injector as recited in claim 11, wherein a plurality of
axial turning vanes are formed within the outer air circuit.
16. A fuel injector as recited in claim 11, wherein the nozzle body
is formed by direct metal laser sintering.
17. A fuel injector for a gas turbine engine comprising: a) a feed
arm having a first and second fuel passages; and b) a nozzle tip
assembly depending from an end of the feed arm, wherein the nozzle
tip assembly includes a nozzle body that is substantially
monolithically formed by direct metal laser sintering and has a
first fuel circuit formed therein communicating with the first fuel
passage of the feed arm, a second fuel circuit formed therein
communicating with the second fuel passage of the feed arm, and an
air circuit formed between the first fuel circuit and the second
fuel circuit.
18. A fuel injector as recited in claim 17, wherein fuel transfer
ports are defined within the nozzle body that extend between the
first fuel circuit and the air circuit.
19. A fuel injector as recited in claim 17, wherein fuel transfer
ports are defined within the nozzle body that extend between the
second fuel circuit and the air circuit.
20. A fuel injector as recited in claim 17, wherein a plurality of
axial turning vanes are formed within the air circuit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The subject invention relates to fuel injectors for gas
turbine engines, and more particularly, to a fuel injector having a
nozzle tip assembly with an additively manufactured nozzle
body.
[0003] 2. Description of Related Art
[0004] Gas turbine engines must satisfy high demands with respect
to reliability, weight, performance, economic efficiency and
durability. Among other things, the use of advanced manufacturing
methods and material selection play a decisive role in meeting
these requirements.
[0005] Conventional methods for manufacturing gas turbine
components include forging and investment casting. For example, the
highly stressed components in the compressor region of a gas
turbine are typically manufactured by forging, whereas the rotor
and stator blades of the turbine are typically manufactured by
investment casting.
[0006] Fuel injectors for gas turbine engines often include a
complex nozzle tip assembly for delivering atomized fuel to the
engine combustor that includes a cast swirler and multiple
sub-assemblies. In addition, intricate assembly methods are
required to meet specified performance criteria for many nozzle
assemblies.
[0007] The conventional construction of a fuel injector nozzle
includes components that are bonded together by braze. The
components typically have milled slots or drilled holes that
control the flow of fuel through the nozzle and prepare the fuel
for atomization. These components are typically nested within one
another and form a narrow diametral gap therebetween which is often
filled with a braze alloy.
[0008] The braze alloy is usually applied as a braze paste, wire
ring, or as a thin sheet shim on the external surfaces or within
pockets inside the assembly. The assembly is then heated and the
braze alloy melts and flows into the narrow diametral gap and
securely bonds the components together upon cooling.
[0009] Such conventional methods and systems generally have been
considered satisfactory for their intended purpose. However, when
using traditional brazing techniques, the braze alloy must flow
from a ring or pocket to the braze area. In doing so, it is often
prone to flow imprecisely when melted.
[0010] In some instances, braze fillets can be formed on or in
certain features. If this happens, intricate or narrow passages can
become plugged. These fillets and plugs can negatively affect
nozzle performance. Moreover, braze may not flow to the desired
braze area in the quantity needed to ensure a proper braze joint.
This is typical when the braze alloy cannot be located in close
proximity to the desired braze joint location.
[0011] The difficulty in controlling braze flow when employing
traditional brazing techniques is a limiting factor in the design
of fuel and air flow passages within a fuel nozzle assembly. That
is, the shape and size of the flow passages is limited by the
ability to control the flow of braze.
[0012] There remains a need in the art for an efficient process to
manufacture complex fuel nozzles that reduces the number of
component parts and sub-assemblies needed for the fuel nozzle
assembly and the use of brazing operations to assemble the nozzle
components.
SUMMARY OF THE INVENTION
[0013] The subject invention is directed to a new and useful fuel
injector for a gas turbine engine. The fuel injector has, among
other things, a nozzle tip assembly that includes a nozzle body
substantially monolithically formed by additive manufacturing.
[0014] By way of example, the nozzle body may be formed by direct
metal laser sintering (DMLS), or a similar additive manufacturing
technique. As a result, the nozzle tip assembly can be manufactured
faster and with fewer components and sub-assemblies than the prior
art nozzle tip assembly for the same fuel injector.
[0015] The monolithically formed nozzle body of the subject
invention has an outer fuel circuit formed therein for
accommodating transfer of a gaseous fuel and an inner fuel circuit
for accommodating transfer of a liquid fuel. In addition, the
nozzle body has an outer air circuit formed between the outer fuel
circuit and the inner fuel circuit.
[0016] Gaseous fuel transfer ports are defined within the nozzle
body that extend between the outer fuel circuit and the outer air
circuit, and liquid fuel transfer ports are defined within the
nozzle body that extend between the inner fuel circuit and the
outer air circuit. In addition, a plurality of axial turning vanes
are formed within the outer air circuit.
[0017] The nozzle tip assembly depends from an end of a feed arm.
The feed arm has a first fuel passage that communicates with and
delivers gaseous fuel to the outer fuel circuit of the nozzle body
and a second fuel passage that communicates with and delivers
liquid fuel to the inner fuel circuit of the nozzle body. The
nozzle tip assembly further comprises a pressure atomizer that is
disposed within an inner air circuit of the nozzle body. The
pressure atomizer can serve as a pilot for the nozzle tip
assembly.
[0018] These and other features of the additively manufactured fuel
injector assembly of the subject invention and the manner in which
it is employed will become more readily apparent to those having
ordinary skill in the art from the following enabling description
of the preferred embodiments of the subject invention taken in
conjunction with the several drawings described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] So that those skilled in the art to which the subject
invention appertains will readily understand how to make and use
the nozzle tip assembly of the subject invention without undue
experimentation, preferred embodiments thereof will be described in
detail herein below with reference to certain figures, wherein:
[0020] FIG. 1 is a cross-sectional view of a prior art fuel
injector for a gas turbine engine, which includes a nozzle tip
assembly constructed from a plurality of separately machined parts
and sub-assemblies that are assembled using numerous braze and weld
joints;
[0021] FIG. 2 is a cross-sectional view of a fuel injector for a
gas turbine engine, which includes a nozzle tip assembly having an
additively manufactured nozzle body providing the structural
features of a plurality of parts and sub-assemblies in a single
monolithic part;
[0022] FIG. 3 is a cross-sectional view of the additively
manufactured nozzle body of the subject invention; and
[0023] FIG. 4 is a cross-sectional view of the additively
manufactured nozzle body shown in FIG. 3, assembled with the
on-axis pressure atomizer that can serve as a pilot for the nozzle
tip assembly.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0024] Referring now to the drawings, there is illustrated in FIG.
1 a prior art fuel injector for a gas turbine engine, which is
designated generally by reference numeral 10. The prior art fuel
injector 10 shown in FIG. 1 is adapted and configured for use in
conjunction with the Allison 501-K gas turbine engine, which has
been a prime mover in many installations around the world for
decades. Since its introduction in 1963, the 501-K has been
continually upgraded to reflect changing technology and
experience.
[0025] The fuel injectors employed on 501-K gas turbine engines can
fulfill a variety of application requirements including gas, liquid
or dual fuel systems with automatic changeover capability. Water
injection may also be employed for emissions control.
[0026] As shown in FIG. 1, the fuel injector 10 includes an
elongated feed arm 12, having an inlet assembly 14 at the upper end
thereof and a nozzle tip assembly 16 at the lower end thereof. The
inlet assembly 14 of fuel injector 10 is designed for dual fuel
applications and therefore includes three separate inlet fittings,
two of which are shown in FIG. 1, namely, inlet fittings 18 and 20.
Each inlet fitting accommodates a separate fuel circuit in the
nozzle tip assembly 16.
[0027] Inlet fitting 18 communicates with a central fuel passage 22
that extends through the main feed arm 12. The central fuel passage
22 preferably delivers gaseous fuel to the nozzle tip assembly 16.
Inlet fitting 20 communicates with a main external feed tube 24 of
the feed arm 12. The main external feed tube 24 delivers main
liquid fuel to the nozzle tip assembly 16. A third inlet fitting
(not shown), communicates with a pilot external feed tube 24a,
which delivers pilot liquid fuel to the nozzle tip assembly 16.
While not illustrated in FIG. 1, those skilled in the art will
readily appreciate that check valves or the like would be
operatively associated with the inlet assembly 14 of feed arm 12 to
control the fuel flow rate to the nozzle tip assembly 16.
[0028] With continuing reference to FIG. 1, the prior art nozzle
tip assembly 16 of fuel injector 10 includes a plurality of
separately machined parts or components that are assembled using
numerous braze and weld joints, which tend to limit the efficient
manufacturability of the assembly.
[0029] More particularly, the prior art nozzle tip assembly 16
includes a generally cylindrical outer shroud 40 and an outer
sleeve 42. An outer gas passage 44 is defined between the outer
shroud 40 and the outer sleeve 42. The outer gas passage 44
communicates with the central fuel passage 22 of feed arm 12. An
end ring 43 supports the rear end portion of the outer sleeve 42
within the shroud 40.
[0030] An air swirler 45 is positioned coaxially within the outer
sleeve 42. An air mixing channel 46 is formed between the outer
surface of the air swirler 45 and the inner surface of the outer
sleeve 42. The air swirler 45 includes a plurality of
circumferentially spaced apart radial swirl vanes 48 disposed
within the air mixing channel 46 for imparting swirl to air flowing
therethrough.
[0031] A plurality of circumferentially disposed gas exit ports 50
extend between the outer gas passage 44 and the air mixing channel
46, upstream from the radial swirl vanes 48. The air mixing channel
46 has a converging outer wall formed by an air lip 52 positioned
downstream from the radial swirl vanes 48.
[0032] The air swirler 45 has a central bore that supports a
separate inner air sleeve 54. A liquid fuel transfer annulus 55 is
defined between the exterior surface of the inner air sleeve 54 and
the interior surface of the air swirler 45. The fuel transfer
annulus 55 receives fuel from a fuel inlet (not shown in FIG. 1)
that communicates with the lower end of fuel tube 24.
[0033] A plurality of radially outwardly extending fuel exit ports
58 extend between the fuel transfer annulus 55 and the air mixing
channel 46. The forward end of the inner air sleeve 54 forms a fuel
conic 60 downstream from the exit ports 58 that defines a
prefilming surface for liquid fuel exiting the ports 58.
[0034] The inner air sleeve 54 defines a central bore that supports
and retains a pressure atomizer 62, which can serve as a pilot for
the nozzle tip assembly 16 under certain operating conditions. The
pressure atomizer 62 has an axial bore 64 extending therethrough
from a proximal inlet end 64a to a distal exit end 64b. The
proximal inlet end 64a of axial bore 64 is preferably threaded to
accept a plug that retains the pressure atomizer distributor and an
associated seal (not shown). The distal exit end 64b is tapered to
effect the flow of pressurize fuel flowing therethrough. The
pressure atomizer 62 also includes a fuel inlet passage 66 that
communicates with the pilot external feed tube 24a. The inlet
passage 66 delivers liquid fuel into the axial bore 64 of the
pressure atomizer 62.
[0035] In sum, the prior art nozzle tip assembly 10 includes the
following separately machined component parts: an outer shroud 40,
outer sleeve 42, end ring 43, air swirler 45, air lip 52, inner air
sleeve 54 and a pressure atomizer 62. Each of these parts must are
joined together using numerous braze and weld joints, which tend to
limit the efficient manufacturability of the assembly 10.
[0036] In contrast to the prior art fuel injector 10, the novel
fuel injector of the subject invention, which is shown in FIG. 2
and designated generally by reference numeral 100, includes a
nozzle tip assembly 116 having a unique additively manufactured,
monolithically formed nozzle body 125 that is specifically shown in
FIG. 3, and includes the structural features of several of the
individual components that are employed in the nozzle tip assembly
16 of the prior art fuel injector 10.
[0037] Those skilled in the art will readily appreciate that the
term additive manufacturing, as used herein, encompasses techniques
such as laser additive deposition, laser metal deposition, direct
laser deposition, direct metal deposition, laser cladding and the
like.
[0038] In accordance with an exemplary embodiment, the present
invention relates to the use of a rapid construction method for
producing the nozzle body 125 of nozzle assembly 116. Specifically,
the invention utilizes a rapid manufacturing technology known as
direct metal laser sintering (DMLS) to manufacture a monolithic
nozzle body that eliminates joints, brazing and other aspects of
the prior art nozzle construction.
[0039] DMLS is an additive layer process that produces a metal
component directly from a CAD model using a laser and a fine metal
powder (e.g., cobalt and/or chrome alloy powders and Nickel-based
alloy powders are especially suited for the turbine nozzle
application disclosed herein, but the invention is not so
limited).
[0040] The CAD model is sliced into thin layers (on the order of
0.02 mm) and the layers are then reconstructed layer by layer, with
the laser fusing programmed areas of each powder layer in
succession to the underlying layer. The layer thickness is
generally chosen based on a consideration of accuracy versus speed
of manufacture. Initially, a steel plate is typically fixed inside
the machine to serve as both a support and a heat sink.
[0041] A dispenser delivers the powder to the support plate and a
coater arm or blade spreads the powder on the plate. The machine
software controls the laser beam focus and movement so that
wherever the laser beam strikes the powder, the powder melts into a
solid. The process continues layer by layer until the buildup is
completed.
[0042] Referring now to FIG. 2, the novel fuel injector 100
includes an elongated feed arm 112, having an inlet assembly 114 at
the upper end thereof and nozzle tip assembly 116 at the lower end
thereof. The inlet assembly 114 of fuel injector 100 includes three
inlet fittings, only two of which are shown, namely, inlet fittings
118 and 120.
[0043] Inlet fitting 118 communicates with a central fuel passage
122 that extends through the main feed arm 112 to deliver gaseous
fuel to the nozzle tip assembly 116. Inlet fitting 120 communicates
with a main external feed tube 124 that delivers main liquid fuel
to the nozzle tip assembly 116. A third inlet fitting (not shown)
communicates with a pilot external feed tube 124a that delivers
pilot liquid fuel to the nozzle tip assembly 116.
[0044] The nozzle tip assembly 116 includes a monolithically formed
nozzle body 125 which defines an outer shroud portion 140 and an
outer sleeve portion 142. An outer gas passage 144 is defined
between the outer shroud portion 140 and the outer sleeve potion
142. The outer gas passage 144 communicates with the central fuel
passage 122 of feed arm 112. The end sections of the outer shroud
portion 140 and the outer sleeve portion 142 are bridged by
integral supporting structure 143.
[0045] An air swirler portion 145 is formed coaxially within the
outer sleeve portion 142 of nozzle body 125. An air mixing channel
146 is formed between the outer surface of the air swirler portion
145 and the inner surface of the outer sleeve portion 142 of nozzle
body 125. The air swirler portion 145 includes a plurality of
circumferentially spaced apart radial swirl vanes 148 that extend
between the air swirler portion 145 and the outer sleeve portion
142 of nozzle body 125. The swirl vanes 148 impart swirl to air
flowing through the air mixing channel 146.
[0046] A plurality of circumferentially disposed gas exit ports 150
extend between the outer gas passage 144 and the air mixing channel
146, upstream from the radial swirl vanes 148. The air mixing
channel 146 has a converging outer wall formed by an integral air
lip portion 152 projecting from the shroud portion 140 downstream
from the radial swirl vanes 148.
[0047] The air swirler portion 145 of nozzle body 125 is
monolithically formed with an inner air sleeve portion 154. A
liquid fuel transfer annulus 155 is defined between the inner air
sleeve portion 154 and the air swirler portion 145. The fuel
transfer annulus 155 receives fuel from a fuel inlet 156 that
communicates with the lower end of fuel tube 124 (see FIG. 2).
[0048] A plurality of radially outwardly extending fuel exit ports
158 extend between the fuel transfer annulus 155 and the air mixing
channel 146. The forward end of the air sleeve 154 forms a fuel
conic 160 downstream from the exit ports 158 that defines a
prefilming surface for liquid fuel exiting the ports 158.
[0049] As best seen in FIG. 4, the inner air sleeve portion 154 of
the air swirler portion 145 has a central pilot air channel 170
extending therethrough. The pilot air channel 170 is dimensioned
and configured to receive and retain a separate pressure atomizer
162. The pressure atomizer 162, is substantially similar to the
pressure atomizer 62 of fuel injector 10 shown in FIG. 1. It is not
monolithically formed with the nozzle body 125. Indeed, it is the
only component of the nozzle assembly 126 that is formed
monolithically with the additively manufactured nozzle body 125 of
nozzle tip assembly 116.
[0050] The pressure atomizer 162 also includes a pilot liquid fuel
inlet 166 that communicates with the pilot liquid fuel feed tube
124a. The fuel inlet passage 166 delivers pilot liquid fuel into
the axial bore of the pressure atomizer 162.
[0051] While the subject invention has been shown and described
with reference to a preferred embodiment, those skilled in the art
will readily appreciate that various changes and/or modifications
may be made thereto without departing from the spirit and scope of
the subject invention as defined by the appended claims.
* * * * *