U.S. patent application number 09/922367 was filed with the patent office on 2003-02-06 for counterflow plate-fin heat exchanger with extended header fin.
This patent application is currently assigned to Ingersoll-Rand Energy Systems Corporation. Invention is credited to Haplau-Colan, Alexander, Nash, James S..
Application Number | 20030024696 09/922367 |
Document ID | / |
Family ID | 25446931 |
Filed Date | 2003-02-06 |
United States Patent
Application |
20030024696 |
Kind Code |
A1 |
Haplau-Colan, Alexander ; et
al. |
February 6, 2003 |
Counterflow plate-fin heat exchanger with extended header fin
Abstract
A plate-fin heat exchanger includes a stacked array of cells.
Each cell includes top and bottom sheets defining manifolds and
header finned members disposed between the top and bottom sheets.
The top and bottom sheets include substantially planar portions,
diverging portions angled with respect to the planar portions, and
divergence edges defined between the planar and diverging portions.
The header finned member extends beyond the divergence edges of the
top and bottom sheets and is supported in cantilevered fashion
within the manifold.
Inventors: |
Haplau-Colan, Alexander;
(Hampton, NH) ; Nash, James S.; (West Newbury,
MA) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH LLP
3773 CORPORATE PARKWAY
SUITE 360
CENTER VALLEY
PA
18034-8217
US
|
Assignee: |
Ingersoll-Rand Energy Systems
Corporation
Portsmouth
NH
|
Family ID: |
25446931 |
Appl. No.: |
09/922367 |
Filed: |
August 3, 2001 |
Current U.S.
Class: |
165/153 ;
165/167 |
Current CPC
Class: |
F28D 9/0043 20130101;
F28F 3/025 20130101; F02C 7/08 20130101 |
Class at
Publication: |
165/153 ;
165/167 |
International
Class: |
F28D 001/02; F28F
003/08 |
Claims
1. A recuperated microturbine engine comprising: an air compressor
operable to create a flow of compressed air; a combustor operable
to mix the flow of compressed air with a fuel, and operable to
combust the fuel/air mixture to create an expanding flow of
products of combustion; a turbine and generator assembly
communicating with said combustor and operable in response to the
expanding flow of products of combustion to generate electricity,
said turbine and generator assembly exhausting a flow of hot
exhaust gases; and a recuperator including at least one cell
through the inside of which said flow of compressed air flows, and
around the outside of which the flow of exhaust gases flows, said
recuperator preheating the flow of compressed air with heat from
the flow of exhaust gases before the flow of compressed air is
delivered to said combustor, said recuperator cell having top and
bottom sheets and at least one header finned member sandwiched
between and metallurgically bonded to said top and bottom sheets
within the inside of said cell, said recuperator also including
inlet and outlet manifolds communicating with the inside of said
cell to direct the flow of the compressed air into and out of said
cell, respectively; wherein said header finned member includes a
cantilever portion that is not directly metallurgically bonded to
said top and bottom sheets and that extends into one of said inlet
and outlet manifolds in a cantilever fashion, said cantilever
portion including a free end edge within said manifold; wherein
said flow of compressed air creates a high pressure environment
within said cell, which environment imparts tensile stresses to
said header finned member; and wherein said free end edge is
subject to a substantially reduced state of tensile stress due to
said cantilever extension of said header finned member into said
manifold.
2. The engine of claim 1, wherein said header finned member is a
first header finned member, said first header finned member
extending into said inlet manifold, and wherein said cell further
includes a second header finned member metallurgically bonded to
said top and bottom sheets and having a cantilever portion
extending into said outlet manifold.
3. The engine of claim 1, wherein said at least one cell includes a
plurality of substantially identical cells arranged in a stacked
configuration, said plurality of cells being metallurgically bonded
to each other, and wherein said cells define exhaust gas flow
spaces between said cells through which the flow of exhaust gases
flows.
4. The engine of claim 1, wherein said top and bottom sheets each
include a substantially flat portion, a diverging portion angled
with respect to said substantially flat portion, and a divergence
edge defined between said substantially flat portion and said
diverging portion, wherein said flat portions of said top and
bottom sheets are substantially parallel to each other, wherein
said diverging portion of said top sheet extends away from said
bottom sheet and said diverging portion of said bottom sheet
extends away from said top sheet, and wherein said cantilever
portion is cantilevered with respect to said divergence edges.
5. The engine of claim 4, wherein said header finned member is
metallurgically bonded to said flat portions of said top and bottom
plates.
6. The engine of claim 4, wherein said divergence edge at least
partially defines a boundary of one of said inlet and outlet
manifolds.
7. A heat exchanger cell comprising: top and bottom sheets each
including a manifold opening, said top and bottom sheets being
positioned in stacked relation relative to one another to align
their respective manifold openings; and a header finned member
disposed between and metallurgically bonded to said top and bottom
sheets, said header finned member having a cantilever portion
extending into said manifold openings in cantilever fashion, said
cantilever portion being free from a direct metallurgical bond to
said top and bottom sheets, said cantilever portion terminating in
a free end edge; wherein said cell is adapted to receive a high
pressure fluid therein that creates tensile stresses in said header
finned member; and wherein the tensile stresses on said free end
edge are substantially less than those on the portion of said
header finned member that is metallurgically bonded to said top and
bottom sheets by virtue of said cantilever portion being free from
direct metallurgical bond to said top and bottom sheets.
8. The cell of claim 7, wherein said top and bottom sheets each
include a substantially planar portion, a diverging portion, and a
divergence edge defined between said planar and diverging portions,
and wherein said cantilever portion is cantilevered with respect to
said divergence edge of at least one of said top and bottom
sheets.
9. A plate-fin heat exchanger comprising a first cell including: a
top sheet and a bottom sheet each having a substantially planar
portion and a diverging portion angled with respect to said planar
portion and joined to said planar portion along a divergence edge,
said diverging portion of each sheet at least partially defining a
manifold opening generally aligned with a manifold opening at least
partially defined by the diverging portion of the other sheet; and
a formed member between and metallurgically bonded to said planar
portions of said top and bottom sheets and having a cantilever
portion extending into said manifold openings and terminating in a
free end edge, said cantilever portion being free from a direct
metallurgical bond to said top and bottom sheets; wherein said
diverging portions of said top and bottom sheets both extend away
from said finned member and wherein said divergence edges of said
top and bottom sheets are metallurgically bonded to said finned
member, and said cantilever portion is cantilevered with respect to
said divergence edge.
10. The plate-fin heat exchanger of claim 9, further comprising a
second cell substantially identical to said first cell and
including a top sheet having a diverging portion metallurgically
bonded to said diverging portion of said bottom sheet of said first
cell.
Description
BACKGROUND
[0001] The invention relates to recuperators primarily for use in
gas turbine engines, and more particularly to a fin construction
for the header portions of such recuperators.
SUMMARY
[0002] The present invention provides a cell construction for a
recuperator that is preferably used in a recuperated microturbine
engine. The cell includes top and bottom sheets having aligned
manifold openings. The cell also includes a header finned member
disposed between the top and bottom sheets and having a cantilever
portion extending into the manifold openings in cantilevered
fashion. The header finned member is metallurgically bonded to the
top and bottom sheets. The cantilever portion includes a free end
edge. A high pressure fluid, such as compressed air is supplied
into the cell, and causes a state of tensile stress in the header
finned member. The free end edge of the cantilever portion is
exposed to substantially reduced tensile stress because the
cantilever portion is free from a direct metallurgical bond to the
top and bottom sheets.
[0003] Other features and advantages of the invention will become
apparent to those skilled in the art upon review of the following
detailed description, claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is an exploded view of a recuperated microturbine
engine embodying the invention.
[0005] FIG. 2 is a perspective view of the recuperator of the
engine illustrated in FIG. 1.
[0006] FIG. 3 is an exploded view of one cell of the
recuperator.
[0007] FIG. 4 is an enlarged perspective view of a portion of the
recuperator.
[0008] FIG. 5 is a graphical representation of the tensile stress
on the header finned members of the recuperator.
[0009] Before one embodiment of the invention is explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangements
of the components set forth in the following description or
illustrated in the drawings. The invention is capable of other
embodiments and of being practiced or being carried out in various
ways. Also, it is understood that the phraseology and terminology
used herein is for the purpose of description and should not be
regarded as limiting. The use of "including" and "comprising" and
variations thereof herein is meant to encompass the items listed
thereafter and equivalents thereof as well as additional items. The
use of "consisting of and variations thereof herein is meant to
encompass only the items listed thereafter. The use of letters to
identify elements of a method or process is simply for
identification and is not meant to indicate that the elements
should be performed in a particular order.
DETAILED DESCRIPTION
[0010] For the sake of brevity, not all aspects of plate fin heat
exchanger and microturbine combustor technology are discussed
herein. For additional description of that technology, reference is
made to U.S. patent application Ser. Nos. 09/790,464 filed Feb. 22,
2001, 09/668,358 filed Sept. 25, 2000, 09/409,641 filed Oct. 1,
1999, 09/239,647 filed Jan. 29, 1999 (now U.S. Pat. No. 5,983,992),
and 08/792,261 filed Jan. 13, 1997. The entire contents of these
applications are incorporated by reference herein.
[0011] FIG. 1 illustrates a recuperated microturbine engine 10 that
includes a frame 14. A recuperator or heat exchanger 18 is mounted
to the frame 14. As seen in FIG. 2, the recuperator 18 includes a
plurality of stacked cells 22 that are metallurgically bonded
(e.g., by welding and/or brazing) to each other to define an inlet
manifold 26 and an outlet manifold 30. The interior spaces or
volumes of the cells 22 communicate between the inlet and outlet
manifolds 26, 30. Exhaust gas flow spaces are defined between the
cells 22 for a flow of hot exhaust gases 34. The details of the
recuperator construction will be discussed in more detail
below.
[0012] The engine 10 also includes an air compressor 38 that
provides compressed air 40 (FIG. 2) to the inlet manifold 26 of the
recuperator 18 through an air compressor duct (not shown). The
compressed air flows into the cells 22, where it is heated by the
cross-flow of hot exhaust gases 34, and exits the recuperator 18
through the outlet manifold 30 as preheated compressed air 41 (FIG.
2). A combustor 42 is housed within or otherwise communicates with
the outlet manifold 30 of the recuperator 18. The preheated
compressed air 41 exiting the recuperator 18 is mixed with a fuel
(e.g., natural gas), and is then burned by the combustor 42. The
efficiency of the combustor 42 is improved by preheating the
compressed air. During operation of the engine 10, the combustor 42
maintains a substantially continuous explosion that is fed by the
fuel and air mixture. The explosion produces a rapidly-expanding
flow of products of combustion.
[0013] The engine 10 also includes a turbine 46 that receives the
products of combustion from the combustor 42. The expansion of the
products of combustion discussed above drives the turbine 46. The
turbine 46 in turn drives an electric generator 50 to generate
electricity. The turbine 46 also drives the air compressor 38. The
exhaust gases 34 from the turbine 46 are then routed through the
exhaust gas flow spaces in the recuperator 18, as illustrated in
FIG. 2, before the exhaust gases are finally vented to the
atmosphere.
[0014] As seen in FIG. 3, each cell 22 of the recuperator 18
includes top and bottom plates or sheets 58, 62, an internal or
matrix finned member 66, inlet and outlet header finned members 70,
and external finned members 74. The top and bottom sheets 58, 62
define manifold openings 78 that align to define the manifolds 26,
30. The manifold openings 78 and manifolds 26, 30 are generally
cylindrical in the illustrated embodiment, but could have other
configurations.
[0015] As seen in FIGS. 3 and 4, the top and bottom sheets 58, 62
include substantially planar portions 82 and diverging portions 86
angled with respect to the planar portions 82. The diverging
portions 86 and planar portions 82 define a divergence edge 90
therebetween, and the divergence edges 90 define the boundaries of
the manifolds 26, 30. The planar portions 82 of the top sheets 58
are substantially parallel to the planar portions 82 of the bottom
sheets 62.
[0016] The diverging portion 86 of the top sheet 58 of each cell 22
is angled away from the bottom sheet 62 and header finned member 70
of that cell 22, and is angled toward the bottom sheet 62 of the
cell 22 above it. Similarly, the diverging portion 86 of the bottom
sheet 62 of each cell 22 is angled away from the top sheet 58 and
header finned member 70 of that cell 22, and is angled toward the
top sheet 58 of the cell 22 below it. Adjacent cells 22 in the
recuperator 18 are metallurgically bonded to each other where the
diverging portions 86 of the top and bottom sheets 58, 62 come
together. The sheets 58, 62 are also sealed to each other along
their edges to substantially air-tightly seal the interior volume
of the cell 22, except along the divergence edges 90, where the
cell communicates with the respective inlet and outlet manifolds
26, 30.
[0017] The matrix and header finned members 66, 70 are
metallurgically bonded to the top and bottom sheets 58, 62. The
header finned members 70 are thus metallurgically bonded to the top
and bottom sheets 58, 62 along the divergence edge 90. The
compressed air increases pressure within the cells 22 and applies
tensile stress on the matrix and header finned members 66, 70. A
cantilever portion 94 of each header finned member 70 extends
beyond the divergence edge 90 and into the manifolds 26, 30 in a
cantilevered fashion. The cantilever portion 94 is therefore free
from direct metallurgical bond to the top and bottom sheets 58,
62.
[0018] The cantilever portion 94 includes a free end edge 98 that
is not aligned with the divergence edge 90. The free end edge 98 of
the cantilever portion 94 may be cut and not polished or treated
because the stress level on the free end edge 98 is reduced. This
is because the free end edge 98 is not directly exposed to the
tensile stresses in the header finned member 70 caused by the
pressurized air in the cell 22. Rather, the cantilever portion 94
helps resist the tensile loading on the header finned member 70
while reducing the tensile stress on the free end edge 98.
[0019] More specifically, as illustrated in FIG. 5, the tensile
stress on the header finned member 70 decreases over the span of
the cantilever portion 94, and is substantially diminished or
non-existent at the free end edge 98.
* * * * *