U.S. patent application number 13/630164 was filed with the patent office on 2014-08-07 for heat exchange module for a turbine engine.
This patent application is currently assigned to UNITED TECHNOLOGIES CORPORATION. The applicant listed for this patent is John T. Schmitz, Frederick M. Schwarz. Invention is credited to John T. Schmitz, Frederick M. Schwarz.
Application Number | 20140216056 13/630164 |
Document ID | / |
Family ID | 51258084 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140216056 |
Kind Code |
A1 |
Schwarz; Frederick M. ; et
al. |
August 7, 2014 |
HEAT EXCHANGE MODULE FOR A TURBINE ENGINE
Abstract
A heat exchange module is provided for a turbine engine. The
heat exchange module includes a duct and a plurality of heat
exchangers. The duct includes a flowpath defined radially between a
plurality of concentric duct walls. The flowpath extends along an
axial centerline through the duct between a first duct end and a
second duct end. The heat exchangers are located within the
flowpath, and arranged circumferentially around the centerline.
Inventors: |
Schwarz; Frederick M.;
(Glastonbury, CT) ; Schmitz; John T.; (West
Hartford, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schwarz; Frederick M.
Schmitz; John T. |
Glastonbury
West Hartford |
CT
CT |
US
US |
|
|
Assignee: |
UNITED TECHNOLOGIES
CORPORATION
Hartford
CT
|
Family ID: |
51258084 |
Appl. No.: |
13/630164 |
Filed: |
September 28, 2012 |
Current U.S.
Class: |
60/806 ;
415/178 |
Current CPC
Class: |
B64D 33/12 20130101;
F02C 7/12 20130101; B64D 2033/024 20130101; F01D 25/14 20130101;
F05D 2260/20 20130101; Y02T 50/60 20130101; F02K 3/115 20130101;
F28D 2021/0021 20130101; F02K 3/105 20130101; F05D 2260/213
20130101; B64D 33/10 20130101; F28D 2021/0026 20130101; F02C 7/32
20130101; Y02T 50/675 20130101; F28D 7/1676 20130101; B64D 33/08
20130101; F02K 3/077 20130101; F02C 7/185 20130101; F02C 7/14
20130101; F01D 25/08 20130101 |
Class at
Publication: |
60/806 ;
415/178 |
International
Class: |
F02C 7/12 20060101
F02C007/12 |
Claims
1. A heat exchange module for a turbine engine, comprising: a duct
including a flowpath defined radially between a plurality of
concentric duct walls, the flowpath extending along an axial
centerline through the duct between a first duct end and a second
duct end; and a plurality of heat exchangers located within the
flowpath, and arranged circumferentially around the centerline.
2. The heat exchange module of claim 1, wherein a first of the heat
exchangers has an arcuate geometry.
3. The heat exchange module of claim 1, wherein a first of the heat
exchangers has a rectangular geometry.
4. The heat exchange module of claim 3, wherein at least a portion
of a first of the duct walls has a polygonal cross-sectional
geometry.
5. The heat exchange module of claim 4, wherein the first of the
duct walls includes a transition segment that extends axially from
the first duct end to a heat exchanger segment; the heat exchanger
segment has the polygonal cross-sectional geometry; and the
transition segment has a cross-sectional geometry that transitions
from a circular cross-section geometry at the first duct end to the
polygonal cross-sectional geometry at the heat exchanger
segment.
6. The heat exchange module of claim 5, wherein the first of the
duct walls further includes a second transition segment that
extends axially from the second duct end to the heat exchanger
segment; and the second transition segment has a cross-sectional
geometry that transitions from a circular cross-sectional geometry
at the second duct end to the polygonal cross-sectional geometry at
the heat exchanger segment.
7. The heat exchange module of claim 4, wherein at least a portion
of a second of the duct walls has a polygonal cross-sectional
geometry.
8. The heat exchange module of claim 1, further comprising an
actuator that moves a first of the heat exchangers between a
deployed position and a stowed position.
9. The heat exchange module of claim 8, wherein the first of the
heat exchangers is located within the flowpath in the deployed
position, and is located adjacent to the flowpath in the stowed
position.
10. The heat exchange module of claim 8, wherein the first of the
heat exchangers pivots within the flowpath about an axis between
the deployed position and the stowed position.
11. The heat exchange module of claim 8, further comprising: a
baffle arranged circumferentially between the first and a second of
the heat exchangers; and a second actuator that moves a baffle
between a deployed position and a stowed position.
12. A turbine engine with an axial centerline, comprising: a core
comprising a compressor section, a combustor section and a turbine
section; an annular engine flowpath defined radially between a
plurality of turbine engine cases, the engine flowpath extending
axially between an inlet and an outlet and circumferentially around
the core; and a heat exchange module connected to a first of the
turbine engine cases, and comprising a duct including an annular
duct flowpath defined radially between a plurality of duct walls,
the duct flowpath extending axially through the duct and coupled
with the engine flowpath; and a plurality of heat exchangers
located with the duct flowpath, and arranged circumferentially
around the centerline.
13. The turbine engine of claim 12, wherein a first of the heat
exchangers has a rectangular geometry; and at least a portion of a
first of the duct walls has a polygonal cross-sectional
geometry.
14. The turbine engine of claim 13, wherein the first of the duct
walls includes a transition segment that extends axially from a
first duct end to a heat exchanger segment; the heat exchanger
segment has the polygonal cross-sectional geometry; and the
transition segment has a cross-sectional geometry that transitions
from a circular cross-section geometry at the first duct end to the
polygonal cross-sectional geometry at the heat exchanger
segment.
15. The turbine engine of claim 14, wherein the first of the duct
walls further includes a second transition segment that extends
axially from a second duct end to the heat exchanger segment; and
the second transition segment has a cross-sectional geometry that
transitions from a circular cross-sectional geometry at the second
duct end to the polygonal cross-sectional geometry at the heat
exchanger segment.
16. The turbine engine of claim 12, further comprising: an actuator
that moves a first of the heat exchangers between a deployed
position and a stowed position; wherein the first of the heat
exchangers is located within the duct flowpath in the deployed
position, and is located adjacent to the duct flowpath in the
stowed position.
17. The turbine engine of claim 12, further comprising: an actuator
that moves a first of the heat exchangers between a deployed
position and a stowed position; wherein the first of the heat
exchangers pivots within the duct flowpath about an axis between
the deployed position and the stowed position.
18. The turbine engine of claim 12, wherein the first of the
turbine engine cases includes a plurality of case segments, and a
first of the duct walls is connected axially between the case
segments.
19. The turbine engine of claim 12, further comprising an annular
second engine flowpath defined radially between one of the turbine
engine cases and a third turbine engine case, the second engine
flowpath extending axially between a second inlet and a second
outlet, and circumferentially around the core and within the engine
flowpath.
20. A turbine engine with an axial centerline, comprising: a core
comprising a compressor section, a combustor section and a turbine
section; an annular engine flowpath defined radially between a
plurality of turbine engine cases, the engine flowpath extending
axially between an inlet and an outlet and circumferentially around
the core; and a heat exchange module connected to a first of the
turbine engine cases, and comprising a duct including a duct
flowpath defined by a duct wall that extends circumferentially
about the centerline, the duct flowpath extending axially through
the duct and circumferentially about the centerline, wherein the
duct flowpath is coupled inline with the engine flowpath; and a
plurality of heat exchangers located with the duct flowpath, and
arranged circumferentially about the centerline.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] This disclosure relates generally to a turbine engine and,
more particularly, to a heat exchanger for a turbine engine.
[0003] 2. Background Information
[0004] Various turbine engine systems as well as aircraft systems
may generate significant quantities of heat energy as a byproduct
during operation. Examples of such a turbine engine system include
an electrical generator and a lubrication system. An example of
such an aircraft system includes a high powered sensor system. One
or more of these systems may be cooled by circulating a cooling
medium between respective system heat exchangers and a flowpath
heat exchanger. The system heat exchangers are thermally coupled
with the systems being cooled. The flowpath heat exchanger is
arranged within a flowpath of the engine. The flowpath heat
exchanger, for example, may be fixedly mounted in the flowpath to a
turbine engine case.
[0005] There is a need in the art for an improved flowpath heat
exchanger.
SUMMARY OF THE DISCLOSURE
[0006] According to an aspect of the invention, a heat exchange
module is provided for a turbine engine. The heat exchange module
includes a duct and a plurality of heat exchangers. The duct
includes a flowpath defined radially between a plurality of
concentric duct walls. The flowpath extends along an axial
centerline through the duct between a first duct end and a second
duct end. The heat exchangers are located within the flowpath, and
arranged circumferentially around the centerline.
[0007] According to another aspect of the invention, a turbine
engine with an axial centerline is provided that includes a core,
annular engine flowpath defined radially between a plurality of
turbine engine cases, and a heat exchange module connected to a
first of the turbine engine cases. The core includes a compressor
section, a combustor section and a turbine section. The engine
flowpath extends axially between an inlet and an outlet and
circumferentially around the core. The heat exchange module
includes a duct and a plurality of heat exchangers. The duct
includes an annular duct flowpath formed radially between a
plurality of duct walls, where the duct flowpath extends axially
through the duct and is coupled with the engine flowpath. The heat
exchangers are located with the duct flowpath, and arranged
circumferentially around the centerline.
[0008] According to another aspect of the invention, a turbine
engine with an axial centerline is provided that includes a core,
an annular engine flowpath defined radially between a plurality of
turbine engine cases, and a heat exchange module connected to a
first of the turbine engine cases. The core includes a compressor
section, a combustor section and a turbine section. The engine
flowpath extends axially between an inlet and an outlet and
circumferentially around the core. The heat exchange module
includes a duct and a plurality of heat exchangers. The duct
includes a duct flowpath defined by a duct wall that extends
circumferentially about the centerline. The duct flowpath extends
axially through the duct and circumferentially about the
centerline, and the duct flowpath is fluidly coupled inline with
the engine flowpath. The heat exchangers are located with the duct
flowpath and arranged circumferentially about the centerline.
[0009] One or more of the heat exchangers may have an arcuate
geometry.
[0010] One or more of the heat exchangers may have a rectangular
geometry.
[0011] At least a portion of a first of the duct walls may have a
polygonal cross-sectional geometry.
[0012] The first of the duct walls may include a transition segment
that extends axially from the first duct end to a heat exchanger
segment, which has a polygonal cross-sectional geometry. The
transition segment may have a cross-sectional geometry that
transitions from a circular cross-section geometry at the first
duct end to the polygonal cross-sectional geometry at the heat
exchanger segment. The first of the duct walls may also include a
second transition segment that extends axially from the second duct
end to the heat exchanger segment. The second transition segment
may have a cross-sectional geometry that transitions from a
circular cross-sectional geometry at the second duct end to the
polygonal cross-sectional geometry at the heat exchanger
segment.
[0013] At least a portion of a second of the duct walls may have a
polygonal cross-sectional geometry.
[0014] An actuator may be included that moves a first of the heat
exchangers between a deployed position and a stowed position. In
one embodiment, the first of the heat exchangers may be located
within the duct flowpath in the deployed position, and located
adjacent to (e.g., outside of) the duct flowpath in the stowed
position. In another embodiment, the first of the heat exchangers
may pivot within the duct flowpath about an axis between the
deployed position and the stowed position.
[0015] A baffle may be arranged circumferentially between a first
and a second of the heat exchangers. A second actuator may be
included that moves the baffle between a deployed position and a
stowed position.
[0016] The first of the turbine engine cases may include a
plurality of case segments. A first of the duct walls may be
connected axially between the case segments.
[0017] An annular second engine flowpath may be formed radially
between one of the turbine engine cases and a third turbine engine
case. The second engine flowpath may extend axially between a
second inlet and a second outlet, and circumferentially around the
core and within the engine flowpath.
[0018] The foregoing features and the operation of the invention
will become more apparent in light of the following description and
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a sectional illustration of a turbine engine;
[0020] FIG. 2 is an illustration of a heat exchange module included
in the turbine engine of FIG. 1;
[0021] FIG. 3 is a partial, sectional illustration of the heat
exchange module of FIG. 2;
[0022] FIG. 4 is an illustration of a broadside of a heat exchanger
included in the heat exchange module of FIG. 2;
[0023] FIG. 5A is a partial, sectional illustration of the heat
exchange module of FIG. 2 with a heat exchanger in a deployed
position;
[0024] FIG. 5B is a partial, sectional illustration of the heat
exchange module of FIG. 5A with the heat exchanger in a stowed
position;
[0025] FIG. 6A is a partial, sectional illustration of another heat
exchange module with a heat exchanger in a deployed position;
[0026] FIG. 6B is a partial, sectional illustration of the heat
exchange module of FIG. 6A with the heat exchanger in a stowed
position;
[0027] FIG. 7A is a partial, sectional illustration of another heat
exchange module with a heat exchanger in a deployed position;
[0028] FIG. 7B is a partial, sectional illustration of the heat
exchange module of FIG. 7A with the heat exchanger in a stowed
position;
[0029] FIG. 8 is a partial cross-sectional illustration of the heat
exchange module of FIG. 2;
[0030] FIG. 9 is an illustration of another heat exchange module;
and
[0031] FIG. 10 is a sectional illustration of another turbine
engine.
DETAILED DESCRIPTION OF THE INVENTION
[0032] FIG. 1 illustrates a turbine engine 12 that extends along an
axial centerline 14 between an upstream airflow inlet 16 and a
downstream airflow exhaust 18. The engine 12 includes a fan section
19, a compressor section 20, a combustor section 21, a turbine
section 22, and/or an augmentor section 23. The compressor section
20, the combustor section 21 and the turbine section 22 form a core
24 of the engine 12.
[0033] The engine also includes a plurality of concentric turbine
engine cases 26, 28 and 30, a plurality of concentric annular
engine flowpaths 32, 34 and 36, and a heat exchange module 38. The
first case 26 houses the core 24 and the augmentor section 23. The
second case 28 extends circumferentially around the first case 26,
and includes a plurality of axial second case segments 40. The
third case 30 houses the fan section 19 and extends
circumferentially around the second case 28. The third case 30
includes a plurality of axial third case segments 42.
[0034] The first engine flowpath 32 (e.g., a central core flowpath)
is defined by the first case 26, and extends axially through the
core 24 and the augmentor section 23. The second engine flowpath 34
(e.g., a primary bypass flowpath) is defined radially between the
first case 26 and the second case 28, and extends axially between
an inlet and an outlet. The third engine flowpath 36 (e.g., a
secondary bypass flowpath) is defined radially between the second
case 28 and the third case 30, and extends axially between an inlet
and an outlet.
[0035] Referring to FIGS. 2 and 3, the heat exchange module 38
includes an annular duct 44 and one or more flowpath heat
exchangers 46. The duct 44 extends axially between an upstream
first duct end 48 and a downstream second duct end 50. The duct 44
includes a radial inner first duct wall 52, a radial outer second
duct wall 54, and an annular duct flowpath 56.
[0036] The first duct wall 52 includes a first transition segment
58, a heat exchanger segment 59 and a second transition segment 60.
The first transition segment 58 extends axially from the first duct
end 48 to the heat exchanger segment 59. The first transition
segment 58 has a cross-sectional geometry that transitions from a
circular cross-sectional geometry at the first duct end 48 to an
equilateral polygonal cross-sectional geometry at the heat
exchanger segment 59. The heat exchanger segment 59 extends axially
between the first and the second transition segments 58 and 60, and
has an equilateral polygonal cross-sectional geometry. The second
transition segment 60 extends axially from the heat exchanger
segment 59 to the second duct end 50. The second transition segment
60 has a cross-sectional geometry that transitions from an
equilateral polygonal cross-sectional geometry at the heat
exchanger segment 59 to a circular cross-sectional geometry at the
second duct end 50.
[0037] The second duct wall 54 includes a first transition segment
62, a heat exchanger segment 63 and a second transition segment 64.
The first transition segment 62 extends axially from the first duct
end 48 to the heat exchanger segment 63. The first transition
segment 62 has a cross-sectional geometry that transitions from a
circular cross-sectional geometry at the first duct end 48 to an
equilateral polygonal cross-sectional geometry at the heat
exchanger segment 63. The heat exchanger segment 63 extends axially
between the first and the second transition segments 62 and 64, and
has an equilateral polygonal cross-sectional geometry. The second
transition segment 64 extends axially from the heat exchanger
segment 63 to the second duct end 50. The second transition segment
64 has a cross-sectional geometry that transitions from an
equilateral polygonal cross-sectional geometry at the heat
exchanger segment 63 to a circular cross-sectional geometry at the
second duct end 50.
[0038] The second duct wall 54 also includes one or more annular
flanges 66 and 67. The first flange 66 extends radially out from
the first transition segment 62 at (e.g., on, adjacent or
proximate) the first duct end 48. The second flange 67 extends
radially out from the second transition segment 64 at the second
duct end 50.
[0039] The duct flowpath 56 is defined radially between the first
duct wall 52 and the second duct wall 54. The duct flowpath 56
extends axially through the duct 44 between the first duct end 48
and the second duct end 50. Referring to FIG. 1, the duct flowpath
56 is concentric with the first and the second engine flowpaths 32
and 34.
[0040] Each of the heat exchangers 46 of FIG. 4 includes a
plurality of spaced parallel tubes 68 and 70 that extend laterally
(e.g., circumferentially or tangentially) between a first manifold
72 and a second manifold 74. The heat exchanger 46 embodiment of
FIG. 4 is configured as a counterflow heat exchanger. The first
manifold 72 includes a distribution region 76 with an inlet 77 and
a collection region 78 with an outlet 79. The tubes 68 fluidly
couple the distribution region 76 to the second manifold 74. The
tubes 70 fluidly couple the second manifold 74 to the collection
region 78. The present invention, however, is not limited to any
particular heat exchanger type and/or configuration.
[0041] Referring to FIGS. 2 and 3, the heat exchangers 46 are
arranged circumferentially around the centerline 14. The heat
exchangers 46 are located within the duct flowpath 56 and extend
radially between the first duct wall 52 and the second duct wall
54. The heat exchangers 46 are fixedly and/or movably connected to
one or both of the heat exchanger segments 59 and 63.
[0042] Referring to FIG. 1, the duct flowpath 56 is fluidly coupled
inline with the third engine flowpath 36. The first duct wall 52 is
arranged axially between the second case segments 40. The second
duct wall 54 is arranged axially between and connected to the third
case segments 42. The first flange 66 is connected to a
corresponding annular flange of the third case segment 42 with a
plurality of fasteners. The second flange 67 is connected to a
corresponding annular flange of the third case segment 42 with a
plurality of fasteners.
[0043] Various turbine engine systems such as electrical
generators, lubrication systems, etc. as well as aircraft systems
such as high powered sensor systems, etc. may generate significant
quantities of heat energy as a byproduct during operation. One or
more of these systems may be cooled by circulating a cooling medium
such as air, coolant, oil, etc. between respective system heat
exchangers and the heat exchange module 38. The system heat
exchangers, for example, may transfer the heat energy generated by
the turbine engine and/or aircraft systems into the cooling medium.
The heat exchanger 46 of FIGS. 3 and 4 may receive the now
relatively hot cooling medium from one or more of the system heat
exchangers. The distribution region 76 directs the cooling medium
into the tubes 68. The tubes 68 may transfer heat energy from the
cooling medium into bypass gas, which is flowing through the duct
flowpath 56 and the heat exchanger 46 from the third engine
flowpath 36 (see FIG. 1). The second manifold 74 directs the
cooling medium from the tubes 68 to the tubes 70. The tubes 70 may
transfer additional heat energy from the cooling medium into the
bypass gas. The collection region 78 collects the now relatively
cool cooling medium from the tubes 70, and the heat exchanger 46
may provide the cooling medium back to the system heat exchangers
to repeat the heat exchange process.
[0044] In some embodiments, one or more (e.g., each) of the heat
exchangers 46 are adapted to move between a deployed position and a
stowed position. For example, each heat exchanger 46 may radially
translate into and out of the duct flowpath 56 between the deployed
position of FIG. 5A and the stowed position of FIG. 5B. In another
example, each heat exchanger 46 may pivot (e.g., approximately
90.degree.) within the duct flowpath 56 about a lateral axis 80
between the deployed position of FIG. 6A and the stowed position of
FIG. 6B. In still another example, each heat exchanger 46 may pivot
(e.g., approximately 90.degree.) within the duct flowpath 56 about
a radial axis 82 between the deployed position of FIG. 7A and the
stowed position of FIG. 7B.
[0045] In the deployed position, each heat exchanger 46 is arranged
such that a relatively large quantity of the bypass gas flows
through the heat exchanger 46. In the embodiment of FIG. 5A, for
example, the heat exchanger 46 is located within the duct flowpath
56 with its broadside 84 arranged substantially perpendicular to
the flow of the bypass gas. In contrast, in the stowed position,
each heat exchanger 46 is arranged such that a relatively small
quantity or none of the bypass gas flows through the heat
exchangers 46. In the embodiment of FIG. 5B, for example, the heat
exchanger 46 is located adjacent to and outside of the duct
flowpath 56. In the embodiment of FIGS. 6B and 7B, the heat
exchanger 46 is located within the duct flowpath 56 with its
broadside 84 arranged substantially parallel to the flow of the
bypass gas. In this manner, the heat exchange module 38 reduces
pressure drop across the third engine flowpath 36 (see FIG. 1) and
may increase engine efficiency and/or power by selectively moving
one or more of the heat exchangers 46 into the stowed position when
the cooling needs for the turbine engine and/or aircraft systems
are relatively low.
[0046] FIG. 8 illustrates an actuator 86 adapted to move at least
one of the heat exchangers 46 between the deployed position of FIG.
5A and the stowed position of FIG. 5B. The actuator 86 includes an
electric motor 88 that turns one or more threaded jackscrews 90.
Opposite narrow-side ends 92 of the heat exchanger 46 are connected
to the jackscrews 90 by way of a set of threaded followers 94
(e.g., threaded nuts). As the motor 88 rotates the jackscrews 90,
the followers 94 and the heat exchanger 46 connected thereto move
radially into and out of the duct flowpath 56 between the deployed
and the stowed positions.
[0047] A person of skill in the art will recognize various actuator
configurations other than that described above and illustrated in
FIG. 8 may be utilized to move the heat exchangers 46 between the
deployed and the stowed positions. The actuator, for example, may
include a motor that is connected to a respective heat exchanger by
way of a shaft, where the actuator pivots the heat exchanger about
an axis of the shaft between the deployed and the stowed positions.
The present invention therefore is not limited to any particular
actuator configurations.
[0048] Referring still to the embodiment of FIG. 8, the inlet 77
and/or the outlet 79 of each heat exchanger 46 are connected to
flexible hoses 96, only one of which is shown for ease of
illustration. The flexible hoses 96 enable the heat exchanger 46 to
move between the deployed and the stowed positions.
[0049] FIG. 9 illustrates an alternate embodiment heat exchange
module 98. In contrast the to the heat exchange module 38 of FIG.
2, the first and the second duct walls 52 and 54 of the heat
exchange module 98 have circular cross-sectional geometries. In
addition, the heat exchange module 98 includes one or more baffles
100. The baffles 100 are adapted to direct the bypass gas through
the heat exchangers 46 by substantially plugging spaces between
adjacent heat exchangers 46. One or more of the baffles 100 may
have similar broadside geometries to those of the heat exchangers
46. In some embodiments, one or more of the baffles 100 are fixedly
connected between the first and the second duct walls 52 and 54. In
other embodiments, one or more of the baffles 100 are adapted to
move between the deployed and the stowed positions in a similar
manner as described above with respect to the heat exchangers
46.
[0050] In some embodiments, the broadside 84 of one or more of the
heat exchangers 46 has a rectangular geometry as illustrated in
FIG. 2. In other embodiments, the broadside 84 of one or more of
the heat exchangers 46 has an arcuate geometry as illustrated in
FIG. 9. The present invention therefore is not limited to any
particular heat exchanger geometries.
[0051] A person of skill in the art will recognize the heat
exchange module 38 may be fluidly coupled inline with other engine
flowpaths than that described above and illustrated in FIG. 1. In
some embodiments, for example as illustrated in FIG. 10, the heat
exchange module 38 may be fluidly coupled inline with the second
engine flowpath 34. The present invention therefore is not limited
to any particular heat exchange module placement within a turbine
engine and/or turbine engine configuration.
[0052] The terms "upstream", "downstream", "inner" and "outer" are
used to orientate the heat exchanger modules described above
relative to the turbine engines and the centerline. A person of
skill in the art will recognize, however, the heat exchanger
modules may be utilized in other orientations than those described
above. In alternate embodiments, for example, the heat exchangers
may move radially into and out of the inner duct wall. The present
invention therefore is not limited to any particular heat exchanger
module spatial orientations.
[0053] While various embodiments of the present invention have been
disclosed, it will be apparent to those of ordinary skill in the
art that many more embodiments and implementations are possible
within the scope of the invention. For example, the present
invention as described herein includes several aspects and
embodiments that include particular features. Although these
features may be described individually, it is within the scope of
the present invention that some or all of these features may be
combined within any one of the aspects and remain within the scope
of the invention. Accordingly, the present invention is not to be
restricted except in light of the attached claims and their
equivalents.
* * * * *