U.S. patent application number 14/994634 was filed with the patent office on 2017-07-13 for heat exchangers.
The applicant listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Andrzej E. Kuczek, Brian St. Rock, Joseph Turney.
Application Number | 20170198979 14/994634 |
Document ID | / |
Family ID | 57714512 |
Filed Date | 2017-07-13 |
United States Patent
Application |
20170198979 |
Kind Code |
A1 |
St. Rock; Brian ; et
al. |
July 13, 2017 |
HEAT EXCHANGERS
Abstract
A heat exchanger includes a body made of polymer, a plurality of
first flow channels defined in the body, and a plurality of second
flow channels defined in the body. The second flow channels fluidly
isolated from the first flow channels. The first flow channels and
second flow channels are arranged in a checkerboard pattern.
Inventors: |
St. Rock; Brian; (Andover,
CT) ; Kuczek; Andrzej E.; (Bristol, CT) ;
Turney; Joseph; (Amston, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
|
|
Family ID: |
57714512 |
Appl. No.: |
14/994634 |
Filed: |
January 13, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F 21/062 20130101;
F28F 1/006 20130101; F28F 2255/18 20130101; F28D 7/1653 20130101;
F28F 7/02 20130101; F28F 21/06 20130101; F28D 7/163 20130101 |
International
Class: |
F28D 7/16 20060101
F28D007/16; F28F 21/06 20060101 F28F021/06; F28F 7/02 20060101
F28F007/02; F28F 1/00 20060101 F28F001/00 |
Claims
1. A heat exchanger, comprising: a body made of polymer; a
plurality of first flow channels defined in the body; and a
plurality of second flow channels defined in the body, the second
flow channels fluidly isolated from the first flow channels,
wherein the first flow channels and second flow channels are
arranged in a checkerboard pattern.
2. The heat exchanger of claim 1, wherein the first and/or second
flow channels can include a changing flow area along a length of
the body.
3. The heat exchanger of claim 2, wherein the changing flow area
increases a first flow area toward a first flow outlet of the heat
exchanger.
4. The heat exchanger of claim 3, wherein the changing flow area
decreases a second flow area toward the first flow outlet as the
first flow area increases.
5. The heat exchanger of claim 2, wherein the first and/or second
flow channels include a changing flow area shape.
6. The heat exchanger of claim 5, wherein the changing flow area
shape includes a first polygonal flow area at a first flow inlet
which transitions to a second polygonal flow area having more sides
at a first flow outlet.
7. The heat exchanger of claim 5, wherein the changing flow area
shape includes a first polygonal flow area at a second flow inlet
which transitions to a second polygonal flow area having more sides
at a second flow outlet.
8. The heat exchanger of claim 1, wherein the hot and second flow
channels include a rhombus shape such that all surfaces form
primary heat transfer surfaces wherein each surface includes a hot
side defining a portion of a first flow channel and a cold side
defining a portion of a second flow channel.
9. The heat exchanger of claim 1, wherein the first and/or second
flow channels include at least one of a hexagonal shape or an
octagonal shape.
10. The heat exchanger of claim 1, wherein the first and/or second
flow channels include a rectilinear shape.
11. The heat exchanger of claim 1, wherein the first and/or second
flow channels include a polygonal shape.
12. A method for manufacturing a heat exchanger, comprising;
forming a body out of polymer to include a plurality of first flow
channels and a plurality of second flow channels such that the
second flow channels are fluidly isolated from the first flow
channels, and such that the first flow channels and second flow
channels are arranged in a checkerboard pattern.
13. The method of claim 12, wherein forming the heat exchanger
includes additively manufacturing the heat exchanger.
Description
BACKGROUND
[0001] 1. Field
[0002] The present disclosure relates to heat exchangers, more
specifically to more thermally efficient heat exchangers.
[0003] 2. Description of Related Art
[0004] Conventional multi-layer sandwich cores are constructed out
of flat sheet metal dividing plates, spacing bars, and two
dimensional thin corrugated fins brazed together. The fabrication
process is well established and relatively simple. However, the
manufacturing simplicity has a negative impact on the performance
and limits the ability to control thermal efficiency.
[0005] Such conventional methods and systems have generally been
considered satisfactory for their intended purpose. However, there
is still a need in the art for improved heat exchangers. The
present disclosure provides a solution for this need.
SUMMARY
[0006] A heat exchanger includes a body made of polymer, a
plurality of first flow channels defined in the body, and a
plurality of second flow channels defined in the body. The second
flow channels fluidly isolated from the first flow channels. The
first flow channels and second flow channels are arranged in a
checkerboard pattern.
[0007] The first and/or second flow channels can include a changing
flow area along a length of the body. The changing flow area can
increase a first flow area toward a first flow outlet of the heat
exchanger. The changing flow area can decrease a second flow area
toward the first flow outlet as the first flow area increases.
[0008] The first and/or second flow channels can include a changing
flow area shape. The changing flow area shape can include a first
polygonal flow area at a first flow inlet which transitions to a
second polygonal flow area having more sides at a first flow
outlet. The changing flow area shape can include a first polygonal
flow area at a second flow inlet which transitions to a second
polygonal flow area having more sides at a second flow outlet.
[0009] The hot and second flow channels can include a rhombus shape
such that all surfaces form primary heat transfer surfaces wherein
each surface includes a hot side defining a portion of a first flow
channel and a cold side defining a portion of a second flow
channel. In certain embodiments, the first and/or second flow
channels can include at least one of a hexagonal shape or an
octagonal shape. In certain embodiments, the first and/or second
flow channels can include a rectilinear shape, a polygonal shape,
or any other suitable shape.
[0010] In accordance with at least one aspect of this disclosure, A
method for manufacturing a heat exchanger can include forming a
body out of polymer to include a plurality of first flow channels
and a plurality of second flow channels such that the second flow
channels are fluidly isolated from the first flow channels, and
such that the first flow channels and second flow channels are
arranged in a checkerboard pattern. Forming the heat exchanger can
include additively manufacturing the heat exchanger.
[0011] These and other features of the systems and methods of the
subject disclosure will become more readily apparent to those
skilled in the art from the following detailed description taken in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] So that those skilled in the art to which the subject
disclosure appertains will readily understand how to make and use
the devices and methods of the subject disclosure without undue
experimentation, embodiments thereof will be described in detail
herein below with reference to certain figures, wherein:
[0013] FIG. 1A is a perspective view of an embodiment of a heat
exchanger in accordance with this disclosure, showing a hot flow
inlet/cold flow outlet of the heat exchanger;
[0014] FIG. 1B is a perspective cross-sectional view of the heat
exchanger of FIG. 1A, showing a middle portion of the heat
exchanger;
[0015] FIG. 1C is a perspective cross-sectional view of the heat
exchanger of FIG. 1A, showing a hot flow outlet/cold flow inlet of
the heat exchanger;
[0016] FIG. 1D is a scaled up view of a portion of the heat
exchanger of FIG. 1A;
[0017] FIG. 2 is a cross-sectional view of an embodiment of a heat
exchanger in accordance with this disclosure;
[0018] FIG. 3 is a cross-sectional view of an embodiment of a heat
exchanger, illustrating a primary surface heat conduction and
secondary surface heat conduction in a non-checkerboard pattern
embodiment; and
[0019] FIG. 4 is a cross-sectional view of an embodiment of a heat
exchanger in accordance with this disclosure, illustrating only
primary surface heat conduction as there are no secondary
surfaces.
DETAILED DESCRIPTION
[0020] Reference will now be made to the drawings wherein like
reference numerals identify similar structural features or aspects
of the subject disclosure. For purposes of explanation and
illustration, and not limitation, an illustrative view of an
embodiment of a heat exchanger in accordance with the disclosure is
shown in FIG. 1A and is designated generally by reference character
100. Other embodiments and/or aspects of this disclosure are shown
in FIGS. 1B-4. The systems and methods described herein can be used
to reduce weight and/or increase performance of heat transfer
systems.
[0021] Referring to FIG. 1A, a heat exchanger 100 includes a body
101, a plurality of first flow channels, e.g., hot flow channels
103 as described herein, defined in the body 101, and a plurality
of second flow channels, e.g., cold flow channels 105 defined in
the body 101. While hot flow channels 103 and the cold flow
channels 105 are described with respect to a relative temperature
of flow therein, it is contemplated that the hot flow channels 103
can be used for cold flow and vice versa, or any other suitable
arrangement.
[0022] The cold flow channels 105 are fluidly isolated from the hot
flow channels 103. At least one of the hot flow channels 103 or the
cold flow channels 105 can include a changing characteristic along
a length of the body 101. However, it is contemplated that the flow
channels 103, 105 can have constant characteristics along the
length of the body 101.
[0023] The hot flow channels 103 and the cold flow channels 105 can
be utilized in a counter-flow arrangement such that cold flow and
hot flow are routed through the heat exchanger 100 in opposing
directions. Also, as shown, the hot flow channels 103 and the cold
flow channels can be arranged such that hot and cold channels 103,
105 alternate (e.g., in a checkerboard pattern as shown).
[0024] The flow channel 103, 105 can include shapes such as one or
more of rhombuses, hexagons, and octagons. However, while the flow
channels 103, 105 are shown as polygons, the shapes need not be
polygonal or rectilinear. As appreciated by those skilled in the
art, polygonal shapes can be described using the four parameters as
described below. In FIG. 1D, the four parameters are shown. As
shown, the full width A and height B are always greater than zero.
The secondary width C and height D can be zero up to the full width
and height. If C>0 and D>0, the shape is an octagon, if
C>0 and D=0 (or C=0 and D>0), the shape is a hexagon, and if
C=0 and D=0, the shape is a rhombus.
[0025] Any other suitable flow area shapes for the hot flow
channels 103 and/or the cold flow channels 105 are contemplated
herein. For example, as shown in FIG. 2, a heat exchanger 200 can
include elliptical flow channels 203 and/or non-elliptical flow
channels 205 (e.g., rounded cross shaped) defined in body 201.
[0026] As shown in FIGS. 1A, 1B, and 1C, one or more flow channels
103, 105 can include changing characteristics. The changing
characteristics can include a changing flow area. For example, the
changing flow area can increase a hot flow area toward a hot flow
outlet of the heat exchanger 100 (e.g., as shown in transitioning
from FIG. 1A, through FIG. 1B, to FIG. 1C). Similarly, the changing
flow area can decrease a cold flow area toward the hot flow outlet
as the hot flow area increases (which may be a function of the
increasing hot flow area in order to maintain total area of the
body 101). It is contemplated that one or more of the hot flow
channels 103 or the cold flow channels 105 may maintain a constant
flow area or change in any other suitable manner.
[0027] In certain embodiments, the changing characteristic of the
hot and/or cold flow channels 103, 105 can include a changing flow
area shape. In certain embodiments, the changing flow area shape
can include a first polygonal flow area at a hot flow inlet (e.g.,
a rhombus as shown in FIGS. 1A and 1B) which transitions to a
second polygonal flow area having more sides at a hot flow outlet
(e.g., a hexagon as shown in FIG. 3). Also as shown, the changing
flow area shape can include a first polygonal flow area at a cold
flow inlet (e.g., a rhombus as shown in FIGS. 1C and 1B) which
transitions to a second polygonal flow area having more sides at a
cold flow outlet (e.g., a hexagon as shown in FIG. 1A). Any other
suitable changing shape along a length of the body 101 is
contemplated herein (e.g., any desired change of A, B, C, and/or D
as shown in FIG. 1D).
[0028] The body 101 can be made of metal and/or any other suitable
material. For example, the body 101 can be made of a polymer (e.g.,
plastic) or other suitable insulator material. One having ordinary
skill in the art would not endeavor to use polymer as most polymers
are considered thermal insulators, and, thus, the use of polymer is
counter-intuitive for heat exchanger material. However, due to a
reduction and/or elimination of secondary surfaces (e.g., surfaces
where heat must travel through more material than the thickness of
the walls) as described below, polymer can be utilized, especially
in thin-walled applications, because the conduction path through
the polymer (e.g., plastic) is very short in certain embodiments of
the disclosure.
[0029] For example, referring to FIG. 3, an embodiment of a body
301 is shown having a non-checkered scheme (e.g., a planar
alignment scheme as is typical in plate-fin heat exchangers). As
can be seen, primary heat conduction path (a) flows across the
thickness of only two walls from hot channels 303 to cold channels
305. Secondary heat conduction path (b) travels a much longer path
through the material of body 301, which causes an efficiency loss.
However, referring to FIG. 4, the hot and cold flow channels 103,
105 can include a suitable shape (e.g., a rhombus shape as shown)
such that all surfaces form primary heat transfer surfaces wherein
each surface includes a hot side defining a portion of a hot flow
channel 103 and a cold side defining a portion of a cold flow
channel 105. It is contemplated that other shapes (e.g., as
described above) can be used with a polymer body 101, however, the
minimizing secondary heat transfer surfaces can improve the thermal
efficiency.
[0030] It is contemplated that the heat exchanger 100 can include
any suitable header (not shown) configured to connect the hot flow
channels 103 to a hot flow source (not shown) while isolating the
hot flow channels 103 from the cold flow channels 105. The header
may be formed monolithically with the body 101 of the heat
exchanger 100 or otherwise suitably attached to cause the hot flow
channels 103 to converge together and/or to cause the cold flow
channels 105 to converge together.
[0031] In accordance with at least one aspect of this disclosure, a
method for manufacturing a heat exchanger 100 includes forming a
body 101 to include a plurality of hot flow channels 103 and a
plurality of cold flow channels such that the cold flow channels
105 are fluidly isolated from the hot flow channels 103, and such
that at least one of the hot flow channels 103 or the cold flow
channels 105 have a changing characteristic along a length of the
body 101. Forming the heat exchanger 100 can include additively
manufacturing the heat exchanger 100 using any suitable method
(e.g., powder bed fusion, electron beam melting, polymer
deposition).
[0032] Embodiments of this disclosure can allow maximization of
primary surface area for heat exchange while allowing flexibility
to increase or decrease the ratio of hot side to cold side flow
area. Being able to change the relative amount of flow area on each
side of the heat exchanger is necessary to fully utilize the
pressure drop available on each side. Embodiments as described
above allow for enhanced control of flow therethrough, a reduction
of pressure drop, control of thermal stresses, easier integration
with a system, and reduced volume and weight. Unlike conventional
multi-layer sandwich cores, embodiments as described above allow
for channel size adjustment for better impedance match across the
core.
[0033] Further, in additively manufactured embodiments, since the
core (e.g., body 101) can be made out of a monolithic material, the
material can be distributed to optimize heat exchange and minimize
structural stresses, thus minimizing the weight. Bending stresses
generated by high pressure difference between cold and hot side are
greatly reduced by adjusting curvature of the walls and
appropriately sized corner fillets. Such solution reduces weight,
stress, and material usage since the material distribution can be
optimized and since the material works in tension instead of
bending.
[0034] As described above, the certain embodiments can be
additively manufactured (e.g., printed) as one piece out of
polymer. Polymer as a heat exchanger material can offer a
significant weight and cost benefit, and the drawbacks of using
polymer (e.g., due to low thermal conductivity) can be
significantly reduced through improving the heat conduction path
(e.g., via the checkerboard pattern/reduction of secondary heat
transfer surfaces of flow channels 103, 105 as described above).
Hence, the conductive resistance of certain embodiments, even
though made out of polymer, has negligible effect on performance
and allows dramatic weight and cost savings. The resistance through
a primary surface made of polymer will generally be smaller than
the convective resistance between the walls and fluids so that the
thermal conductivity of the polymer has little impact on the
overall performance of the heat exchanger.
[0035] The methods and systems of the present disclosure, as
described above and shown in the drawings, provide for heat
exchangers with superior properties including reduced weight and/or
increased efficiency. While the apparatus and methods of the
subject disclosure have been shown and described with reference to
embodiments, those skilled in the art will readily appreciate that
changes and/or modifications may be made thereto without departing
from the spirit and scope of the subject disclosure.
* * * * *