U.S. patent application number 17/034147 was filed with the patent office on 2021-01-14 for fluid cooling systems for a gas turbine engine.
The applicant listed for this patent is General Electric Company. Invention is credited to Daniel Jason Erno, William Dwight Gerstler, Narendra Digamber Joshi.
Application Number | 20210010376 17/034147 |
Document ID | / |
Family ID | 1000005109670 |
Filed Date | 2021-01-14 |
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United States Patent
Application |
20210010376 |
Kind Code |
A1 |
Erno; Daniel Jason ; et
al. |
January 14, 2021 |
FLUID COOLING SYSTEMS FOR A GAS TURBINE ENGINE
Abstract
A heat exchanger includes an airfoil configured to be positioned
in a coolant stream. The airfoil includes a pressure sidewall and a
suction sidewall coupled to the pressure sidewall. The suction
sidewall and the pressure sidewall define a leading edge and a
trailing edge opposite the leading edge. The leading edge defines
an impingement zone wherein the coolant stream is configured to
impinge the airfoil. The heat exchanger also includes at least one
channel defined within the airfoil between the pressure sidewall
and the suction sidewall. The at least one channel is at least
partially defined within the impingement zone proximate the leading
edge.
Inventors: |
Erno; Daniel Jason; (Clifton
Park, NY) ; Joshi; Narendra Digamber; (Guilderland,
NY) ; Gerstler; William Dwight; (Niskayuna,
NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
1000005109670 |
Appl. No.: |
17/034147 |
Filed: |
September 28, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15424021 |
Feb 3, 2017 |
10830056 |
|
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17034147 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 9/065 20130101;
F05D 2250/185 20130101; F16N 39/02 20130101; F02C 7/14 20130101;
F02K 3/06 20130101; F05D 2260/201 20130101; F05D 2240/121 20130101;
F01D 25/18 20130101; F05D 2220/36 20130101; F01D 25/162 20130101;
F01D 5/187 20130101; F05D 2260/213 20130101; F05D 2260/22141
20130101 |
International
Class: |
F01D 5/18 20060101
F01D005/18; F02K 3/06 20060101 F02K003/06; F01D 9/06 20060101
F01D009/06; F01D 25/18 20060101 F01D025/18; F02C 7/14 20060101
F02C007/14; F16N 39/02 20060101 F16N039/02 |
Claims
1. A heat exchanger comprising: an airfoil configured to be
positioned in a coolant stream, said airfoil comprising: a pressure
sidewall; and a suction sidewall coupled to said pressure sidewall,
said suction sidewall and said pressure sidewall define a leading
edge and a trailing edge opposite said leading edge, said leading
edge defines an impingement zone wherein the coolant stream is
configured to impinge said airfoil; and at least one channel
defined within said airfoil between said pressure sidewall and said
suction sidewall, said at least one channel at least partially
defined within the impingement zone proximate said leading
edge.
2. The heat exchanger in accordance with claim 1, wherein said at
least one channel is configured to receive a fluid stream such that
heat is removed from the fluid stream at least in part through the
coolant stream impinging on said leading edge.
3. The heat exchanger in accordance with claim 1, wherein said
suction sidewall and said pressure sidewall further define a root
portion and a tip portion opposite said root portion, said at least
one channel comprises: an inlet section extending from said root
portion to adjacent said tip portion proximate said leading edge;
and an outlet section extending from adjacent said tip portion to
said root potion such that said at least one channel is
substantially U-shaped.
4. The heat exchanger in accordance with claim 3, wherein said at
least one channel is adjacent said pressure sidewall.
5. The heat exchanger in accordance with claim 1, wherein said
suction sidewall and said pressure sidewall further define a root
portion and a tip portion opposite said root portion, said at least
one channel comprises: an inlet section extending from said root
portion to adjacent said tip portion proximate said leading edge;
an outlet section extending from adjacent said tip portion to said
root portion; and at least one middle section extending from said
inlet section at said tip portion towards said root portion and
from said root portion towards said tip portion and said outlet
section such that said at least one channel is substantially
S-shaped.
6. The heat exchanger in accordance with claim 5, wherein said at
least one channel is adjacent said pressure sidewall.
7. An outlet guide vane comprising: an airfoil comprising: a
pressure sidewall; and a suction sidewall coupled to said pressure
sidewall, said suction sidewall and said pressure sidewall define a
leading edge and a trailing edge opposite said leading edge, said
leading edge defines an impingement zone wherein the coolant stream
is configured to impinge said airfoil; and a heat exchanger
comprising at least one channel defined within said airfoil between
said pressure sidewall and said suction sidewall, said at least one
channel at least partially defined within the impingement zone
proximate said leading edge.
8. The outlet guide vane in accordance with claim 7, wherein said
suction sidewall and said pressure sidewall further define a root
portion and a tip portion opposite said root portion, said at least
one channel comprises: an inlet section extending from said root
portion to adjacent said tip portion proximate said leading edge;
and an outlet section extending from adjacent said tip portion to
said root potion such that said at least one channel is
substantially U-shaped.
9. The outlet guide vane in accordance with claim 7, wherein said
suction sidewall and said pressure sidewall further define a root
portion and a tip portion opposite said root portion, said at least
one channel comprises: an inlet section extending from said root
portion to adjacent said tip portion proximate said leading edge;
an outlet section extending from adjacent said tip portion to said
root portion; and at least one middle section extending from said
inlet section at said tip portion towards said root portion and
from said root portion towards said tip portion and said outlet
section such that said at least one channel is substantially
S-shaped.
10. A turbofan engine comprising: a core engine; a bypass duct at
least partially extending about said core engine; and a plurality
of circumferentially spaced outlet guide vanes extending between
said core engine and said bypass duct, at least one outlet guide
vane of said plurality of outlet guide vanes comprising: an airfoil
comprising: a pressure sidewall; and a suction sidewall coupled to
said pressure sidewall, said suction sidewall and said pressure
sidewall define a leading edge and a trailing edge opposite said
leading edge, said leading edge defines an impingement zone wherein
the coolant stream is configured to impinge said airfoil; and a
heat exchanger comprising at least one channel defined within said
airfoil between said pressure sidewall and said suction sidewall,
said at least one channel at least partially defined within the
impingement zone proximate said leading edge.
11. The turbofan engine in accordance with claim 10, wherein said
suction sidewall and said pressure sidewall further define a root
portion and a tip portion opposite said root portion, said at least
one channel comprises: an inlet section extending from said root
portion to adjacent said tip portion proximate said leading edge;
and an outlet section extending from adjacent said tip portion to
said root potion such that said at least one channel is
substantially U-shaped.
12. The turbofan engine in accordance with claim 10, wherein said
suction sidewall and said pressure sidewall further define a root
portion and a tip portion opposite said root portion, said at least
one channel comprises: an inlet section extending from said root
portion to adjacent said tip portion proximate said leading edge;
an outlet section extending from adjacent said tip portion to said
root portion; and at least one middle section extending from said
inlet section at said tip portion towards said root portion and
from said root portion towards said tip portion and said outlet
section such that said at least one channel is substantially
S-shaped.
Description
PRIORITY INFORMATION
[0001] The present application claims priority to, and is a
divisional application of, U.S. patent application Ser. No.
15/424,021 filed on Feb. 3, 2017, which is incorporated by
reference herein.
BACKGROUND
[0002] The field of the disclosure relates generally to gas turbine
engines and, more specifically, to fluid cooling systems for a gas
turbine engine.
[0003] Gas turbine engines, for example turbofans, typically
include a circulating oil system for lubricating and cooling engine
components such as bearings, gearboxes, and electrical generators.
In operation, the engine oil absorbs heat from the engine
components that will then be removed from the oil before
recirculating. As gas turbine engines become larger, faster, and
more powerful and efficient, more heat within the engine oil will
need to be removed.
[0004] At least some known oil systems include one or more heat
exchangers that facilitate removing heat from the engine oil. For
example, air-to-oil heat exchangers, such as air cooled oil coolers
(ACOCs), are used to remove heat from the engine oil. The ACOCs may
be placed on a surface of a bypass duct of the turbofan and use
bypass air flow as a coolant flow to remove heat from the engine
oil flow therein. However, the ACOCs also create aerodynamic drag
in the fan air flow, thereby reducing thrust of the turbofan. In
another example, fuel-to-oil heat exchangers are additionally or
alternatively used to remove heat from the engine oil. The
fuel-to-oil heat exchangers use fuel flow as a coolant flow to
remove heat from the engine oil flow therein. However, when fuel is
subjected to high temperatures, hydrocarbon reactions are
accelerated resulting in new organic compounds, also known as gum
or varnish, which forms and can aggregate within fuel system
components. Additionally, fuel flow in turbofans decreases as the
turbofan fuel efficiency increases.
BRIEF DESCRIPTION
[0005] In one aspect, a heat exchanger is provided. The heat
exchanger includes an airfoil configured to be positioned in a
coolant stream. The airfoil includes a pressure sidewall and a
suction sidewall coupled to the pressure sidewall. The suction
sidewall and the pressure sidewall define a leading edge and a
trailing edge opposite the leading edge. The leading edge defines
an impingement zone wherein the coolant stream is configured to
impinge the airfoil. The heat exchanger also includes at least one
channel defined within the airfoil between the pressure sidewall
and the suction sidewall. The at least one channel is at least
partially defined within the impingement zone proximate the leading
edge.
[0006] In another aspect, an outlet guide vane is provided. The
outlet guide vane includes an airfoil including a pressure
sidewall, and a suction sidewall coupled to the pressure sidewall.
The suction sidewall and the pressure sidewall define a leading
edge and a trailing edge opposite the leading edge. The leading
edge defines an impingement zone wherein the coolant stream is
configured to impinge the airfoil. The outlet guide vane further
includes a heat exchanger including at least one channel defined
within the airfoil between the pressure sidewall and the suction
sidewall. The at least one channel is at least partially defined
within the impingement zone proximate the leading edge.
[0007] In still another aspect, a turbofan engine is provided. The
turbofan engine includes a core engine, a bypass duct at least
partially extending about the core engine, and a plurality of
circumferentially spaced outlet guide vanes extending between the
core engine and the bypass duct. At least one outlet guide vane of
the plurality of outlet guide vanes includes an airfoil including a
pressure sidewall, and a suction sidewall coupled to the pressure
sidewall. The suction sidewall and the pressure sidewall define a
leading edge and a trailing edge opposite the leading edge. The
leading edge defines an impingement zone wherein the coolant stream
is configured to impinge the airfoil. The outlet guide vane further
includes a heat exchanger including at least one channel defined
within the airfoil between the pressure sidewall and the suction
sidewall. The at least one channel is at least partially defined
within the impingement zone proximate the leading edge.
DRAWINGS
[0008] These and other features, aspects, and advantages of the
present disclosure will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0009] FIG. 1 is a schematic view of an exemplary turbofan engine,
i.e., a gas turbine engine;
[0010] FIG. 2 is a perspective view of an exemplary heat exchanger
that may be used with the turbofan engine shown in FIG. 1;
[0011] FIG. 3 is a side view of an alternative heat exchanger that
may be used with the turbofan engine shown in FIG. 1;
[0012] FIG. 4 is a side view of another alternative heat exchanger
that may be used with the turbofan engine shown in FIG. 1;
[0013] FIG. 5 is a cross-sectional view taken along 5-5 of the heat
exchanger shown in FIG. 4;
[0014] FIG. 6 is a side view of a further alternative heat
exchanger that may be used with the turbofan engine shown in FIGS.
1; and
[0015] FIG. 7 is a cross-sectional view taken along 7-7 of the heat
exchanger shown in FIG. 6.
[0016] Unless otherwise indicated, the drawings provided herein are
meant to illustrate features of embodiments of the disclosure.
These features are believed to be applicable in a wide variety of
systems comprising one or more embodiments of the disclosure. As
such, the drawings are not meant to include all conventional
features known by those of ordinary skill in the art to be required
for the practice of the embodiments disclosed herein.
DETAILED DESCRIPTION
[0017] In the following specification and the claims, reference
will be made to a number of terms, which shall be defined to have
the following meanings.
[0018] The singular forms "a", "an", and "the" include plural
references unless the context clearly dictates otherwise.
[0019] "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, and that the
description includes instances where the event occurs and instances
where it does not.
[0020] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a
change in the basic function to which it is related. Accordingly, a
value modified by a term or terms, such as "about",
"approximately", and "substantially", are not to be limited to the
precise value specified. In at least some instances, the
approximating language may correspond to the precision of an
instrument for measuring the value. Here and throughout the
specification and claims, range limitations may be combined and/or
interchanged. Such ranges are identified and include all the
sub-ranges contained therein unless context or language indicates
otherwise.
[0021] As used herein, the terms "axial" and "axially" refer to
directions and orientations extending substantially parallel to a
longitudinal axis of a gas turbine engine. Moreover, the terms
"radial" and "radially" refer to directions and orientations
extending substantially perpendicular to the longitudinal axis of
the gas turbine engine. In addition, as used herein, the terms
"circumferential" and "circumferentially" refer to directions and
orientations extending arcuately about a longitudinal axis of the
gas turbine engine.
[0022] Embodiments of the present disclosure relate to heat
exchangers within an airfoil that provide a more effective cooling
system for engine oil, from a turbofan engine, channeled
therethrough. Specifically, in the exemplary embodiments, a heat
exchanger includes an outlet guide vane airfoil. The airfoil
includes a pressure sidewall and a suction sidewall, which define a
leading edge and a trailing edge. The leading edge defines an
impingement zone of the airfoil in which a coolant stream impinges
the airfoil. At least one cooling channel is defined within the
airfoil and within the impingement zone proximate the leading edge.
As such, when a fluid, for example, engine oil, is channeled
through the cooling channels, the fluid is channeled through zones
of the airfoil in which the coolant stream is at its most effective
and with an increased heat transfer coefficient. By increasing
efficiency of the airfoil heat exchanger, the amount of heat
extracted from engine oil increases, thereby reducing use of
aerodynamic drag inducing heat exchangers and facilitating a more
efficient turbofan engine.
[0023] FIG. 1 is a schematic view of a gas turbine engine 110,
e.g., a turbomachine, in accordance with an exemplary embodiment of
the present disclosure. In the exemplary embodiment, gas turbine
engine 110 is a high-bypass turbofan jet engine 110, referred to
herein as "turbofan engine 110." As shown in FIG. 1, turbofan
engine 110 defines an axial direction A (extending parallel to a
longitudinal axis 112 provided for reference) and a radial
direction R. In general, turbofan engine 110 includes a fan
assembly 114 and a core turbine engine 116 disposed downstream from
fan assembly 114.
[0024] In the exemplary embodiment, core turbine engine 116
includes a substantially tubular engine casing 118 that defines an
annular inlet 120. Engine casing 118 encases, in serial flow
relationship, a compressor section including a booster or low
pressure (LP) compressor 122 and a high pressure (HP) compressor
124; a combustion section 126; a turbine section including a high
pressure (HP) turbine 128 and a low pressure (LP) turbine 130; and
a jet exhaust nozzle section 132. A high pressure (HP) shaft or
spool 134 drivingly connects HP turbine 128 to HP compressor 124. A
low pressure (LP) shaft or spool 136 drivingly connects LP turbine
130 to LP compressor 122. The compressor section, combustion
section 126, turbine section, and nozzle section 132 together
define a core air flowpath 138.
[0025] Fan assembly 114 includes a fan 140 having a plurality of
fan blades 142 coupled to a disk 144 in a spaced apart manner. As
depicted, fan blades 142 extend outwardly from disk 144 generally
along radial direction R. Fan blades 142 and disk 144 are together
rotatable about longitudinal axis 112 by LP shaft 136 across a
power gear box 145. Power gear box 145 includes a plurality of
gears for adjusting the rotational speed of fan 140 relative to LP
shaft 136 to a more efficient rotational fan speed. In the
exemplary embodiment, turbofan engine 110 is a "geared turbofan
engine" including power gearbox 145. Alternatively, turbofan engine
110 may be a direct drive engine that does not utilize a gearbox
such as, power gear box 145.
[0026] Disk 144 is covered by rotatable front hub 146
aerodynamically contoured to promote an airflow through plurality
of fan blades 142. Additionally, fan assembly 114 and at least a
portion of core turbine engine 116 are surrounded by a nacelle
assembly 148, which includes an annular fan casing or outer nacelle
150 that circumferentially surrounds fan 140 and/or at least a
portion of core turbine engine 116. In the exemplary embodiment,
nacelle 150 is configured to be supported relative to core turbine
engine 116 by a plurality of circumferentially-spaced outlet guide
vanes 152. Moreover, a downstream section 154 of nacelle 150
extends over an outer portion of core turbine engine 116 so as to
define a bypass airflow passage 156 therebetween.
[0027] During operation of turbofan engine 110, a volume of air 158
enters turbofan engine 110 through an associated inlet 160 of
nacelle 150 and/or fan assembly 114. As volume of air 158 passes
across fan blades 142, a first portion, a fan stream 162 of air 158
is directed or routed into bypass airflow passage 156 and a second
portion 164 of air 158 is directed or routed into core air flowpath
138, or more specifically into LP compressor 122. A ratio between
first portion 162 and second portion 164 is commonly known as a
bypass ratio. The pressure of second portion 164 is then increased
as it is routed through HP compressor 124 and into combustion
section 126, where it is mixed with fuel and burned to provide
combustion gases 166.
[0028] Combustion gases 166 are routed through HP turbine 128 where
a portion of thermal and/or kinetic energy from combustion gases
166 is extracted via sequential stages of HP turbine stator vanes
168 that are coupled to engine casing 118 and HP turbine rotor
blades 170 that are coupled to HP shaft or spool 134, thus causing
HP shaft or spool 134 to rotate, thereby supporting operation of HP
compressor 124. Combustion gases 166 are then routed through LP
turbine 130 where a second portion of thermal and kinetic energy is
extracted from combustion gases 166 via sequential stages of LP
turbine stator vanes 172 that are coupled to engine casing 118 and
LP turbine rotor blades 174 that are coupled to LP shaft or spool
136, thus causing LP shaft or spool 136 to rotate which causes
power gear box 145 to rotate LP compressor 122 and/or rotation of
fan 140.
[0029] Combustion gases 166 are subsequently routed through jet
exhaust nozzle section 132 of core turbine engine 116 to provide
propulsive thrust. Simultaneously, the pressure of first portion
162 is substantially increased as first portion 162 is routed
through bypass airflow passage 156 before it is exhausted from a
fan nozzle exhaust section 176 of turbofan engine 110, also
providing propulsive thrust. HP turbine 128, LP turbine 130, and
jet exhaust nozzle section 132 at least partially define a hot gas
path 178 for routing combustion gases 166 through core turbine
engine 116.
[0030] Exemplary turbofan engine 110 depicted in FIG. 1 is by way
of example only, and that in other embodiments, turbofan engine 110
may have any other suitable configuration, including, for example,
a turboprop engine.
[0031] FIG. 2 is a perspective view of an exemplary heat exchanger
200 that may be used with turbofan engine 110 (shown in FIG. 1). In
the exemplary embodiment, heat exchanger 200 is an air cooled oil
cooler (ACOC) and is defined within outlet guide vane (OGV) 152.
Alternatively, heat exchanger 200 is any other heat exchanger,
including, without limitation, an air-to-air heat exchanger, or any
other fluid-to-air heat exchanger utilizing a suitable fluid, such
as, fuel, glycol, or a synthetic heat transfer liquid configured to
interact between a heat source and the fan duct air. OGV 152
includes an airfoil 202 that includes a convex suction sidewall
coupled to a concave pressure sidewall 206. Suction sidewall 204
and pressure sidewall 206 define a leading edge 208 and a trailing
edge 210 opposite leading edge 208. Suction sidewall 204 and
pressure sidewall 206 further define a root portion 212 and a tip
portion 214 opposite root portion 212. An arcuate inner platform
216 is disposed at root portion 212.
[0032] In the exemplary embodiment, heat exchanger 200 includes at
least one cooling channel 218 defined within airfoil 202 between
pressure sidewall 206 and suction sidewall 204 and proximate
leading edge 208. FIG. 2 illustrates a plurality of cooling
channels 218 in a parallel arrangement and defined within airfoil
202, in alternative embodiments, any number of cooling channels 218
are defined therein that enables heat exchanger 200 to operate as
described herein. Cooling channels 218 are substantially U-shaped
and each cooling channel 218 includes at least one inlet section
220 that extends from root portion 212 towards tip portion 214
proximate leading edge 208 and at least one outlet section 222 that
extends from tip portion 214 to root portion 212 adjacent trailing
edge 210. Additionally, cooling channels 218 are defined adjacent
to pressure sidewall 206.
[0033] Moreover, cooling channels 218 are sized to facilitate
maintaining a flow velocity of fluid that is channeled therethrough
for consistent heat transfer, while also maintaining a
predetermined wall thickness of airfoil 202. For example, each
channel 218 has a constant cross-sectional profile along the length
of each channel 218. In alternative embodiments, each channel 218
has a varying cross-sectional profile along the length of each
channel 218 to correspond to the varying shape of airfoil 202. In
another example, each channel 218 has a similar cross-sectional
profile to the adjacent channels 218. In alternative embodiments,
each channel 218 has a different cross-sectional profile to the
adjacent channels 218 to correspond to the varying shape of airfoil
202. In general, those of ordinary skill in the art are capable of
designing the cross-sectional profile of channel 218 to obtain the
desired balance of flow distribution, pressure drop, and heat
transfer.
[0034] In operation, engine oil 224, for example, oil from power
gear box 145 (shown in FIG. 1), is channeled to heat exchanger 200
and through cooling channels 218 by an inlet line 226 of an engine
oil system for heat to be extracted therefrom. Outlet guide vane
152 is positioned in bypass passage 156 (shown in FIG. 1) such that
fan air stream 162 is channeled past airfoil 202 and acts as a
coolant fluid in heat exchanger 200. Specifically, fan air stream
162 impinges airfoil 202 at an impingement zone 228. Impingement
zone 228 is an external impingement zone configured such that an
external fluid, such as fan airstream 162 impinges airfoil 202 at
impingement zone 228. Impingement zone 228 is defined at leading
edge 208 between root portion 212 and tip portion 214 and includes
adjacent portions of pressure sidewall 206 and suction sidewall 204
wherein fan air stream 162 strikes against airfoil 202. After
impinging airfoil 202, fan air stream 162 then flows along both
pressure sidewall 206 and suction sidewall 204 towards trailing
edge 210.
[0035] At impingement zone 228, a heat transfer coefficient of fan
air stream 162 increases because of the stream impinging on airfoil
202. As such, cooling channels 218 are defined proximate to leading
edge 208 and within impingement zone 228 to transfer heat from
engine oil 224 to fan air stream 162. For example, inlet sections
220 are defined proximate to leading edge 208 such that heat
transfer between engine oil 224 and fan air stream 162 is
increased.
[0036] Furthermore, as engine oil 224 is channeled through cooling
channels 218 that are outside of impingement zone 228, heat is
further removed by convection and conduction cooling through fan
stream air 162 channeling along pressure sidewall 206 and suction
sidewall 204. For example, outlet sections 222 are adjacent
pressure sidewall 206. In alternative embodiments, outlet sections
222 are adjacent suction sidewall 204. Although, the heat transfer
coefficient of fan air stream 162 is reduced outside of impingement
zone 228, heat from engine oil 224 is still transferred to fan air
stream 162. The cooled engine oil 224 is then channeled back to the
engine oil system through outlet line 230. Additionally, by
positioning cooling channels 218 away from trailing edge 210, fan
air stream 162 does not have the chance to develop a boundary layer
flow adjacent to pressure sidewall 206 and/or suction sidewall 204
which would further reduce the heat transfer coefficient of fan air
stream 162. Further, cooling channels 218 are positioned adjacent
to pressure sidewall 206 because the boundary layer flow, if any,
develops closer towards trailing edge 210 than on suction sidewall
204.
[0037] FIG. 3 is a side view of an alternative heat exchanger 300
that may be used with turbofan engine 110 (shown in FIG. 1). In
this embodiment, heat exchanger 300 is defined within outlet guide
vane (OGV) 152. Similar to the embodiment described above, OGV 152
includes an airfoil 202 that includes suction sidewall 204,
pressure sidewall 206, leading edge 208, trailing edge 210, root
portion 212, and tip portion 214.
[0038] In this embodiment, heat exchanger 300 includes at least one
cooling channel 302 defined within airfoil 202 between pressure
sidewall 206 and suction sidewall 204 and proximate leading edge
208. FIG. 3 illustrates two cooling channels 302 in a parallel
arrangement and defined within airfoil 202, in alternative
embodiments, any other number of cooling channels 302 are defined
therein that enables heat exchanger 300 to operate as described
herein. Cooling channels 302 are substantially serpentine S-shaped
and each cooling channel 302 includes at least one inlet section
304 that extends from root portion 212 towards tip portion 214
proximate leading edge 208 and at least one outlet section 306 that
extends from tip portion 214 to root portion 212 adjacent trailing
edge 210. Between inlet section 304 and outlet section 306 cooling
channels 302 include at least one middle section 308 that extends
from inlet section 304 at tip portion 214 towards root portion 212
and from root portion 212 back towards outlet section 306 at tip
portion 214. FIG. 3 illustrates three middle sections 308 defined
within airfoil 202, however, in alternate embodiments, any other
number of middle sections 308 are defined therein that enables heat
exchanger 300 to operate as described herein. Additionally, cooling
channels 302 are defined adjacent to pressure sidewall 206. In
alternative embodiments, cooling channels 302 are defined adjacent
to suction sidewall 204.
[0039] Similar to the embodiment described above, cooling channels
302 are sized to facilitate maintaining a flow velocity of fluid
that is channeled therethrough for consistent heat transfer, while
also maintaining a predetermined wall thickness of airfoil 202. For
example, each channel 302 has a constant cross-sectional profile
along the length of each channel 302. In alternative embodiments,
each channel 302 has a varying cross-sectional profile along the
length of each channel 302 to correspond to the varying shape of
airfoil 202. In another example, each channel 302 has a similar
cross-sectional profile to an adjacent channel 302. In alternative
embodiments, each channel 302 has a different cross-sectional
profile to the adjacent channel 302 to correspond to the varying
shape of airfoil 202. In general, those of ordinary skill in the
art can design the cross-sectional profile of channel 302 to obtain
the desired balance of flow distribution, pressure drop, and heat
transfer.
[0040] In operation, engine oil 224 is channeled to heat exchanger
300 and through cooling channels 302 by inlet line 226 for heat to
be extracted therefrom. Specifically, fan air stream 162 impinges
airfoil 202 at impingement zone 228. At impingement zone 228, heat
is transferred from engine oil 224 channeled through cooling
channels 302. Furthermore, as engine oil 224 is channeled through
cooling channels 302 that are outside of impingement zone 228, heat
is further removed by convection and conduction cooling through fan
stream air 162 along pressure sidewall 206. The cooled engine oil
224 is then channeled back to the engine oil system through outlet
line 230.
[0041] FIG. 4 is a side view of another alternative heat exchanger
400 that may be used with turbofan engine 110 (shown in FIG. 1).
FIG. 5 is a cross-sectional view taken along 5-5 of heat exchanger
400 shown in FIG. 4. Referring to FIGS. 4 and 5, in this
embodiment, heat exchanger 400 is defined within outlet guide vane
(OGV) 152. Similar to the embodiments described above, OGV 152
includes an airfoil 202 that includes suction sidewall 204,
pressure sidewall 206, leading edge 208, trailing edge 210, root
portion 212, and tip portion 214. Airfoil 202 further defines a
chord direction 402.
[0042] In this embodiment, heat exchanger 400 includes at least one
cooling channel 404 defined within airfoil 202 between pressure
sidewall 206 and suction sidewall 204 and proximate leading edge
208. For example, cooling channels 404 include an inlet section 406
that extends from root portion 212 towards tip portion 214 adjacent
suction sidewall 204 and an outlet section 408 that extends from
tip portion 214 to root portion 212 adjacent pressure sidewall 206.
Inlet section 406 is positioned within airfoil 202 adjacent suction
sidewall 204 and outlet section 408 is positioned within airfoil
202 adjacent pressure sidewall 206.
[0043] Between inlet section 406 and outlet section 408, cooling
channels 404 include at least one middle section 410 that extends
substantially parallel to and along chord direction 402 from inlet
section 406 towards leading edge 208 adjacent suction sidewall 204
and from leading edge 208 to outlet section 408 adjacent pressure
sidewall 204 such that middle sections 410 correspond to a
perimeter 412 of airfoil 202. As such, middle sections 410 are
substantially parallel to root and tip portions 212 and 214 of
airfoil 202 while also being substantially orthogonal to leading
edge 208. Cooling channels 404 further include a surface 414, and
an impingement zone 416. Impingement zone 416 is an internal
impingement zone configured such that, an internal fluid such as
engine oil 224 will impinge airfoil 202 at impingement zone 416.
Additionally, middle section 410 is disposed at least partially
within impingement zone 416. FIG. 4 illustrates a plurality of
middle sections 410 defined within airfoil 202. However, in
alternative embodiments, any other number of middle sections 410
are defined therein that enables heat exchanger 400 to operate as
described herein.
[0044] Similar to the embodiments described above, cooling channels
404 are sized to facilitate maintaining a flow velocity of fluid
that is channeled therethrough for consistent heat transfer, while
also maintaining a predetermined wall thickness of airfoil 202. For
example, inlet and outlet sections 406 and 408 each have a conical
shape that extend from root portion 212 towards tip portion 214
with each middle section 410 having a similar cross-section area
extending therebetween. As such, the flow velocity of fluid
therethrough is constant throughout each middle section 410. In
alternative embodiments, inlet and outlet sections 406 and 408 may
have other shapes that taper as they extend from root portion 212
towards tip portion 214, with each middle section 410 having a
similar cross section area extending therebetween. A taper is
defined as a narrowing of a shape towards one end.
[0045] In operation, engine oil 224 is channeled to heat exchanger
400 and through cooling channels 404 by inlet line 226 for heat to
be extracted therefrom. Specifically, an external fluid, such as
fan air stream 162 impinges airfoil 202 at impingement zone 228.
Impingement zone 228 is an external impingement zone configured
such that an external fluid impinges airfoil 202 at impingement
zone 228. At impingement zone 228, heat is transferred from engine
oil 224 channeled through cooling channels 404. At impingement zone
416, heat is transferred from engine oil 224 channeled through
cooling channels 404. Furthermore, as engine oil 224 is channeled
through cooling channels 404 that are outside of impingement zone
228, heat is further removed by convection and conduction cooling
through fan stream air 162 along pressure sidewall 206 and suction
sidewall 204. Additionally, in operation, surface 414 provides an
interface between cooling channels 404 and leading edge 208. The
cooled engine oil 224 is then channeled back to the engine oil
system through outlet line 230.
[0046] FIG. 6 is a side view of another alternative heat exchanger
500 that may be used with turbofan engine 110 (shown in FIG. 1).
FIG. 7 is a cross-sectional view taken along 7-7 of heat exchanger
500 shown in FIG. 6. Referring to FIGS. 6 and 7, in this
embodiment, heat exchanger 500 is defined within outlet guide vane
(OGV) 152. Similar to the embodiments described above, OGV 152
includes an airfoil 202 that includes suction sidewall 204,
pressure sidewall 206, leading edge 208, trailing edge 210, root
portion 212, and tip portion 214. Airfoil 202 further defines a
chord direction 402.
[0047] In this embodiment, heat exchanger 500 includes at least one
cooling channel 502 defined within airfoil 202 between pressure
sidewall 206 and suction sidewall 204 and proximate leading edge
208. For example, cooling channels 502 include at least one inlet
section 504 that extends from root portion 212 towards tip portion
214 adjacent suction sidewall 204 and at least one outlet section
506 that extends from tip portion 214 to root portion 212 adjacent
pressure sidewall 206. Inlet sections 504 are positioned within
airfoil 202 adjacent suction sidewall 204 and outlet sections 506
are positioned within airfoil 202 adjacent pressure sidewall
206.
[0048] Between inlet sections 504 and outlet sections 506, cooling
channels 502 include at least one middle section 508 that extends
along chord direction 402 from inlet sections 504 towards leading
edge 208 adjacent suction sidewall 204 and from leading edge 208 to
outlet sections 506 adjacent pressure sidewall 206 such that middle
sections 508 correspond to perimeter 412 of airfoil 202. In this
exemplary embodiment, middle sections 508 are not parallel to root
and tip portions 212 and 214 of airfoil 202 and not orthogonal to
leading edge 208. Middle sections 508 extend at a slope along chord
direction 402. For example, along suction sidewall 204 middle
sections 508 extend in a sloping direction from tip portion 214
towards root portion 212 and along pressure sidewall 206 middle
sections 508 extend in a sloping direction from root portion 212
towards tip portion 214 and then back down to root portion 212 in a
V-shaped pattern. In alternative embodiments, middle sections 508
extend in any other sloping direction that enables heat exchanger
500 to operate as described herein. FIG. 6 illustrates a plurality
of middle sections 508 defined within airfoil 202. However, in
alternative embodiments, any other number of middle sections 508
are defined therein that enables heat exchanger 500 to operate as
described herein.
[0049] Similar to the embodiments described above, cooling channels
502 are sized to facilitate maintaining a flow velocity of fluid
that is channeled therethrough for consistent heat transfer, while
also maintaining a predetermined wall thickness of airfoil 202. For
example, inlet and outlet sections 504 and 506 each have three
conical shaped sections that extend from root portion 212 towards
tip portion 214 with a predetermined number of middle sections 410
having a similar cross-section flow area extending therebetween. As
such, the flow velocity of fluid therethrough is constant
throughout each section of cooling channel 502.
[0050] In operation, engine oil 224 is channeled to heat exchanger
500 and through cooling channels 502 by inlet line 226 for heat to
be extracted therefrom. Specifically, fan air stream 162 impinges
airfoil 202 at impingement zone 228. At impingement zone 228, heat
is transferred from engine oil 224 channeled through cooling
channels 502. Furthermore, as engine oil 224 is channeled through
cooling channels 502 that are outside of impingement zone 228, heat
is further removed by convection and conduction cooling through fan
stream air 162 along pressure sidewall 206 and suction sidewall
204. The cooled engine oil 224 is then channeled back to the engine
oil system through outlet line 230.
[0051] The above-described embodiments provide efficient heat
exchangers defined within an airfoil for extracting heat from
engine oil in a turbofan engine. Specifically, in the exemplary
embodiments, a heat exchanger includes an outlet guide vane
airfoil. The airfoil includes a pressure sidewall and a suction
sidewall, which define a leading edge and a trailing edge. The
leading edge defines an impingement zone of the airfoil in which a
coolant stream impinges the airfoil. At least one cooling channel
is defined within the airfoil and within the impingement zone
proximate the leading edge. As such, when a fluid, for example,
engine oil, is channeled through the cooling channels, the fluid is
channeled through zones of the airfoil in which the coolant stream
is at its most effective and with an increased heat transfer
coefficient, thereby, increasing the efficiency of the heat
exchanger and engine oil cooling system.
[0052] By defining the heat exchanger in the outlet guide vane, the
engine oil cooling system does not create any additional
aerodynamic drag within a bypass duct of the turbofan engine.
Thereby, the heat exchanger increases the bypass ratio and the
efficiency of the turbofan engine. Furthermore, the cooling stream
includes fan bypass air which can accept a large amount of heat
from the engine oil. By increasing efficiency of the airfoil heat
exchanger, the amount of heat extracted from engine oil increases,
and use of other engine oil cooling systems are reduced or even
eliminated. Moreover, by defining the heat exchanger in an existing
engine component, weight of the engine oil cooling system is
decreased. Thereby, the heat exchanger decreases the weight of the
engine oil cooling system and the overall turbofan engine weight,
also, increasing efficiency of the turbofan engine.
[0053] An exemplary technical effect of the systems and methods
described herein includes at least one of: (a) increasing
efficiency of an air cooled oiler cooler heat exchanger; (b)
increasing thermal control of engine oil in turbofan engines; (c)
reducing drag of engine oil cooling systems positioned within a
bypass duct and increasing bypass ratio of the turbofan engine; (d)
reducing overall turbofan engine weight; and (e) increasing overall
turbofan engine efficiency.
[0054] Exemplary embodiments of systems and methods for an air
cooled oiler cooler heat exchanger are described above in detail.
The methods and systems are not limited to the specific embodiments
described herein, but rather, components of systems and/or steps of
the methods may be utilized independently and separately from other
components and/or steps described herein. For example, the method
may also be used in combination with other turbine components, and
are not limited to practice only with the engine oil systems as
described herein. Rather, the exemplary embodiments can be
implemented and utilized in connection with many other turbofan
engine applications.
[0055] Although specific features of various embodiments of the
present disclosure may be shown in some drawings and not in others,
this is for convenience only. In accordance with the principles of
embodiments of the present disclosure, any feature of a drawing may
be referenced and/or claimed in combination with any feature of any
other drawing.
[0056] This written description uses examples to disclose the
embodiments of the present disclosure, including the best mode, and
also to enable any person skilled in the art to practice
embodiments of the present disclosure, including making and using
any devices or systems and performing any incorporated methods. The
patentable scope of the embodiments described herein 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 have 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.
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