U.S. patent application number 12/663590 was filed with the patent office on 2010-09-16 for corrugated micro tube heat exchanger.
This patent application is currently assigned to INTERNATIONAL MEZZO TECHNOLOGIES, INC.. Invention is credited to Charles J. Becnel, Jeffrey John McLean.
Application Number | 20100230081 12/663590 |
Document ID | / |
Family ID | 40853777 |
Filed Date | 2010-09-16 |
United States Patent
Application |
20100230081 |
Kind Code |
A1 |
Becnel; Charles J. ; et
al. |
September 16, 2010 |
Corrugated Micro Tube Heat Exchanger
Abstract
A heat exchanger device having a plurality of substantially
parallel tubes. Each tube has an outer diameter which is less than
or equal to one millimeter and further includes a first end portion
and a second end portion. A first manifold forms an inlet for the
first fluid and further forms a plurality of first openings,
whereby each of the first end portions of the parallel tubes is
attached in a sealed manner to the first manifold so that each tube
is in fluid communication with a respective one of the first
openings. A second manifold spaced from and opposing the first
manifold forms an outlet for the first fluid and further forms a
plurality of second openings, whereby each of the second end
portions of the parallel tubes is attached in a sealed manner to
the second manifold so that each tube is in fluid communication
with a respective one of the second openings. The plurality of
substantially parallel tubes are laterally disposed relative to one
another so that they form at least one corrugated pattern when
viewed in an imaginary plane which intersects and is perpendicular
to the longitudinal axes of the tubes.
Inventors: |
Becnel; Charles J.; (Baton
Rouge, LA) ; McLean; Jeffrey John; (Baton Rouge,
LA) |
Correspondence
Address: |
McGLINCHEY STAFFORD, PLLC;Attn: IP Group
301 Main Street, 14th Floor
BATON ROUGE
LA
70802
US
|
Assignee: |
INTERNATIONAL MEZZO TECHNOLOGIES,
INC.
Baton Rouge
LA
|
Family ID: |
40853777 |
Appl. No.: |
12/663590 |
Filed: |
January 9, 2009 |
PCT Filed: |
January 9, 2009 |
PCT NO: |
PCT/US2009/030614 |
371 Date: |
December 8, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61019911 |
Jan 9, 2008 |
|
|
|
Current U.S.
Class: |
165/173 ;
165/172 |
Current CPC
Class: |
F28F 2260/02 20130101;
F28D 1/05333 20130101 |
Class at
Publication: |
165/173 ;
165/172 |
International
Class: |
F28F 9/02 20060101
F28F009/02; F28F 1/10 20060101 F28F001/10 |
Claims
1. A device for transferring heat from a first fluid to a second
fluid, the device comprising: a plurality of substantially parallel
tubes, each tube having an outer diameter which is less than or
equal to one millimeter, each parallel tube comprising a first end
portion and a second end portion; a first manifold forming an inlet
for the first fluid, the first manifold further forming a plurality
of first openings, each of the first end portions of the parallel
tubes being in sealing relation to the first manifold so that each
tube is in fluid communication with a respective one of the first
openings; and a second manifold spaced from and opposing the first
manifold, the second manifold forming an outlet for the first
fluid, the second manifold further forming a plurality of second
openings, each of the second end portions of the parallel tubes
being in sealing relation to the second manifold so that each tube
is in fluid communication with a respective one of the second
openings; wherein the plurality of substantially parallel tubes are
laterally disposed relative to one another so that they form at
least one corrugated pattern when viewed in an imaginary plane
which intersects and is perpendicular to the longitudinal axes of
the tubes, the corrugated pattern having a thickness, and wherein
the device is adapted so that the first fluid exchanges heat with
the second fluid as the first fluid passes through the parallel
tubes and the second fluid passes between the first and second
manifolds and between but outside of the parallel tubes in a
direction of flow which is generally perpendicular to the direction
of flow of the first fluid through the tubes.
2. A device of claim 1 wherein the spacing between each adjacent
pair of first openings of the plurality of first openings is
substantially equal to the spacing between each adjacent pair of
second openings of the plurality of second openings.
3. A device of claim 1 wherein the spacing between the centers of
each adjacent pair of parallel tubes of the plurality of parallel
tubes is less than three times an outer diameter of each parallel
tube and the outer diameter of each parallel tube is less than or
equal to one millimeter.
4. A device of claim 1 wherein the corrugated pattern has a length
and the thickness of the corrugated pattern varies along the
length.
5. A device of claim I wherein the spacings between each adjacent
pair of parallel tubes of the plurality of parallel tubes are
substantially uniform and each tube of the plurality of tubes has
substantially the same outer diameter.
6. A device of claim 1 wherein the spacings between each adjacent
pair of parallel tubes of the plurality of parallel tubes is not
uniform.
7. A device of claim 1 further comprising one or more support
plates disposed between the first and second manifold, the
plurality of parallel tubes extending through the support plates
and being supported thereby.
8. A method of exchanging heat between a first fluid and a second
fluid, the method comprising providing a housing which defines a
passageway through which the second fluid may flow and across which
extends a plurality of substantially parallel tubes arranged in a
corrugated pattern, when viewed along their longitudinal axes, and
spaced apart from one another so that the plurality of tubes is
substantially porous from any fluid flow direction nonparallel to
the longitudinal axis of the tubes; feeding the first fluid through
the tubes; and feeding the second fluid between and through the
corrugated pattern of parallel tubes, so that heat is transferred
between the first fluid and the second fluid.
9. A method of claim 8, the method further comprising disposing the
parallel tubes relative to one another so that the corrugated
pattern has a thickness and a length, and the thickness varies
along the length.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/019,911, filed Jan. 9, 2008, the disclosure of
which is incorporated herein by reference.
TECHNICAL FIELD
[0002] This invention relates to a heat exchanger device comprising
corrugated micro tubes.
BACKGROUND
[0003] Heat exchangers transfer energy from one fluid to another.
Heat exchangers are typically characterized by heat transfer rates
and corresponding pressure drops of the fluid(s) across the heat
exchanger. In many cases though, volume constraints are provided
and, in these cases, heat exchanger performance may be
characterized by heat transfer/flow area and corresponding pressure
drops. For example, in the case of a liquid-gas heat exchanger, a
typical design challenge is to minimize the face area associated
with the gas side duct, while simultaneously meeting given
specifications relating to allowable pressure drop of the gas
across the heat exchanger, and, of course, heat transfer
requirements.
[0004] Heat exchangers typically consist of cores and headers. The
cores provide two sets of intertwining fluid passages that allow
good thermal coupling between the two fluids without actual mixing
of the fluids. Upon entering the volume occupied by the
intertwining fluid passages, the fluid velocity typically increases
because the hardware within the core that defines the two sets of
fluid channels and promotes heat transfer between the two fluids
necessarily occupies volume and restricts the area available for
flow of both fluids.
[0005] Pressure drop across the core is a function of the drag
associated with the shape of the "heat exchanger hardware" (i. e.
tubes, fins, rectangular channels, etc.), the total distance of
flow through this hardware, and the specific kinetic energy of the
fluid (pV.sup.2). Good heat exchanger design is essentially a
search for an optimum geometry which provides an excellent ratio of
heat transfer/pressure drop within given envelope restraints. A
need exists for heat exchangers with small flow areas (small duct
size) that provide specified rates of heat transfer and specified
low pressure drop.
SUMMARY OF THE INVENTION
[0006] The present invention provides an efficient, simple, and
cost-effective device and/or methodology to provide high heat
transfer/pressure drop ratios that are needed by heat exchanger end
users.
[0007] The present invention addresses a means to simultaneously
achieve high heat transfer/unit duct area and low pressure drop by
the use of a corrugated or serpentine field of closely packed micro
tubes. The width of the corrugated field is much less than the
total length of the serpentine. The serpentine provides effectively
a frontal area much larger than the duct area for one fluid to pass
through the heat exchanger. Because the area is larger, the
velocity of the fluid passing over the serpentine tube bank is
reduced compared to cases involving the same flow rate, same duct
size, but no corrugation. The lower fluid velocity combined with
the short flow length (equal to the width of the serpentine)
results in low pressure drop of the fluid passing over the outside
of the tube bank.
[0008] As noted above, the present invention comprises tightly
packed micro tubes. Micro channel heat exchangers, in general,
provide high heat transfer rates/volume compared to heat exchangers
with larger, more conventional scale, heat exchange passageways.
Heat transfer/unit area is a function of the product hA, where h is
the convection coefficient and A is the area available for heat
transfer. Because both h and A increase as the characteristic
passageway dimension (width or diameter) decreases, the product of
hA/unit volume for micro channel heat exchangers is much greater
than heat exchangers with larger scale. Because micro channel heat
exchangers need less volume to achieve a given rate of heat
exchange, it becomes geometrically feasible to "reshape" this
reduced volume into a thin, serpentine shape that affords
advantages with respect to reducing pressure drop. The advantages
associated with the serpentine shape simply disappear as the
characteristic dimensions of the heat exchanger hardware are
increased.
[0009] It should further be noted that fields of tightly packed
micro tubes offer another advantage with respect to corrugated or
serpentine hardware that dictate a specific flow direction (such as
normal to the local tangent along the serpentine). As the depth of
each crease of a serpentine increases for a given crease width, the
need for the flow direction through the heat exchanger hardware to
be nonspecific becomes more important. Heat exchangers that use a
tube bank, which allow flow in any direction, tend to offer
substantial advantages in corrugated arrangements over flow passage
geometries that do not.
[0010] One particular embodiment of the present invention comprises
a plurality of substantially parallel tubes, each tube having an
outer diameter which is less than or equal to one millimeter. Each
parallel tube comprises a first end portion and a second end
portion. The device further comprises a first manifold forming an
inlet for the first fluid, the first manifold further forming a
plurality of first openings, each of the first end portions of the
parallel tubes being in sealing relation to the first manifold so
that each tube is in fluid communication with a respective one of
the first openings. In addition, the device comprises a second
manifold spaced from and opposing the first manifold, the second
manifold forming an outlet for the first fluid. The second manifold
further forms a plurality of second openings, each of the second
end portions of the parallel tubes being in sealing relation to the
second manifold so that each tube is in fluid communication with a
respective one of the second openings. The plurality of
substantially parallel tubes are laterally disposed relative to one
another so that they form at least one corrugated pattern when
viewed in an imaginary plane which intersects and is perpendicular
to the longitudinal axes of the tubes, the corrugated pattern
having a thickness. The device is adapted so that the first fluid
exchanges heat with the second fluid as the first fluid passes
through the parallel tubes and the second fluid passes between the
first and second manifolds and between but outside of the parallel
tubes in a direction of flow which is generally perpendicular to
the direction of flow of the first fluid through the tubes.
[0011] Another embodiment of the present invention is a method of
exchanging heat between a first fluid and a second fluid. The
method comprises providing a housing which defines a passageway
through which the second fluid may flow and across which extends a
plurality of substantially parallel tubes arranged in a corrugated
pattern, when viewed along their longitudinal axes, and spaced
apart from one another so that the plurality of tubes is
substantially porous from any fluid flow direction nonparallel to
the longitudinal axis of the tubes. The method further comprises.
feeding the first fluid through the tubes and feeding the second
fluid between and through the corrugated bank of parallel tubes, so
that heat is transferred between the first fluid and the second
fluid. In certain embodiments, the housing comprises a first
manifold and second manifold, wherein the parallel tubes are
sealingly attached to the first manifold and second manifold.
[0012] These and other features of this invention will be still
further apparent from the ensuing description, drawings, and
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a perspective view of a corrugated micro tube heat
exchanger consistent with one embodiment of the present
invention.
[0014] FIG. 2 is a perspective view of a plurality of corrugated
micro tubes consistent with another embodiment of the present
invention.
[0015] FIG. 2A is a perspective view of a prior art heat
exchanger.
[0016] FIG. 3 is an exploded view of a corrugated micro tube heat
exchanger in accordance with the embodiment of FIG. 1.
[0017] FIG. 4 is perspective view of a corrugated micro tube heat
exchanger consistent with another embodiment of the present
invention.
[0018] FIG. 5 is a top plan view of a plurality of corrugated micro
tubes in accordance with the embodiment of FIG. 1.
[0019] FIG. 5A is a top plan view of a plurality of corrugated
micro tubes in accordance with another embodiment of the present
invention.
[0020] Like reference numbers or letters are used in the figures to
reference like parts or components amongst the several figures.
FURTHER DETAILED DESCRIPTION OF THE INVENTION
[0021] The present invention enables the exchange of energy from
one fluid to another in a heat exchanger without a significant
reduction in pressure across the core while offering high heat
transfer to weight ratio and reduced volume of the core. It does so
by employing a device and/or methodology which is cost-effective
and offers a relative ease of manufacture.
[0022] Referring now descriptively to the drawings, the attached
figures illustrate one particular embodiment of the invention, in
which a heat exchanger device 10 comprises corrugated micro tubes
12. As seen in FIG. 1, the illustrated embodiment has a plurality
of substantially parallel tubes 12 in fluid communication with a
first manifold 18 and a second manifold 22. Each parallel tube 12
has an outer diameter D (see FIG. 5) of less than or equal to one
millimeter and further comprises a first end portion 14 and a
second end portion 16.
[0023] First manifold 18 forms an inlet (not shown) for the first
fluid A. First manifold 18 further forms a plurality of first
openings 20 (See FIG. 3), whereby each of the first end portions 14
of the parallel tubes 12 is in sealing relation to the first
manifold 18 so that each tube 12 is in fluid communication with a
respective one of the first openings 20. The second manifold 22 is
spaced from and opposes the first manifold 18 and forms an outlet
(not shown) for the first fluid A. Second manifold 22 further forms
a plurality of second openings 21, whereby each of the second end
portions 16 of the parallel tubes 12 is in sealing relation to the
second manifold 22 so that each tube 12 is in fluid communication
with a respective one of the second openings.
[0024] The plurality of substantially parallel tubes 12 are
laterally disposed relative to one another so that they form at
least one corrugated pattern 26 when viewed in an imaginary plane
which intersects and is perpendicular to the longitudinal axes of
the tubes 12. The corrugated pattern 26 has a thickness T (See FIG.
2). The device 10 is adapted so that the first fluid A exchanges
heat with a second fluid B as the first fluid A passes through the
parallel tubes 12 and the second fluid B passes between the first
manifold 18 and second manifold 22 and between but outside of the
parallel tubes 12 in a direction of flow which is generally
perpendicular to the direction of flow of the first fluid through
the tubes 12.
[0025] Turning now to FIG. 2, in an alternate embodiment of the
present invention, plurality of substantially parallel tubes 12 are
illustrated in a corrugated pattern 26. The section of the
corrugated heat exchanger is shown to fit within volume length
L.sub.1.times.width W by height H. The length L.sub.2 of the
corrugated heat exchanger is the length along the midplane of the
bank of tubes having a value greater by virtue of its serpentine
shape than length L.sub.1. The thickness T of the tube bank may
vary along the length L.sub.2 of the plurality of substantially
parallel tubes 12. Thickness T may vary based on the flow stream
through the corrugated pattern 26 and may be varied to correct
non-uniform or uneven flow. The corrugated pattern in any given
embodiment of the present invention may vary to form any serpentine
array. The thickness of the plurality of tubes also may vary at any
point along the length of the serpentine array.
[0026] The corrugated heat exchanger can be compared to a similar
tube-based solid block heat exchanger 34 where the entire volume
L.sub.1.times.H.times.W is occupied by a field of tubes 36 as shown
in FIG. 2A. For the case where fluid flows through the two heat
exchangers in a direction substantially perpendicular to the
H-L.sub.1 plane, the flow length across the tube bank for the case
of the corrugated heat exchanger is T while the flow length through
heat exchanger 34 shown in FIG. 2A is W. Also, the area available
for normal flow through the tube banks is L.sub.2.times.H for the
corrugated heat exchanger and L.sub.1.times.H for the solid block
heat exchanger. The larger flow area associated with the corrugated
heat exchanger and the shorter flow length across the tube bank
associated with the corrugated heat exchanger make it possible to
design heat exchangers with lower pressure drop for given heat
transfer rates and given frontal areas.
[0027] In at least some embodiments of the invention, the
corrugated pattern may be further defined by a grouping of
segments. As shown in FIG. 1, the segment ends 32 are formed at the
juncture of at least two segments 30. The angle .THETA. is the
angle formed from the juncture of at least two segments 30 at the
segment end 32. Segments ends may be porous and permeable to flow
so as to reduce the restriction to flow typically found when angle
.THETA. is small.
[0028] Looking now at FIG. 3, the embodiment as illustrated in FIG.
1 is shown from a different perspective. Previously described
features will only be repeated as necessary. First manifold 18 is
shown separated from the plurality of substantially parallel tubes
12. The plurality of first openings 20 formed from first manifold
18 is in a substantially similar corrugated pattern to the
corrugated pattern 26 of the plurality of substantially parallel
tubes 12. The corrugated pattern 26 of the first openings 20 is
substantially similar to the corrugated pattern 26 of the plurality
of substantially parallel tubes 12 so that the each of the first
end portions 14 of the parallel tubes 12 may be in sealing relation
to the first manifold 18 so that each tube 12 is in fluid
communication with a respective one of the first openings 20. It
should be appreciated that the corrugated pattern 26 of the second
openings 21 is substantially similar to the corrugated pattern 26
of the plurality of substantially parallel tubes 12 so that the
each of the second end portions 16 of the parallel tubes 12 may be
in sealing relation to the second manifold 22 so that each tube 12
is in fluid communication with a respective one of the second
openings.
[0029] As shown in FIG. 4, an alternate embodiment of the present
invention further comprises two support plates 28 disposed between
the first manifold 18 and second manifold 22. The plurality of
parallel tubes 12 extend through the support plates 28 and are
supported thereby. While two support plates 28 are illustrated, the
number of support plates may vary. The number of support plates
needed may depend upon, e.g., the diameter of the tubes, the number
of tubes, the distance between the first and second manifold,
and/or the fluids used in the energy transfer. The support plates
may comprise support plate openings substantially similar in size
to the first openings and the second openings. Spacing between each
adjacent pair of first openings of the plurality of first openings
may be substantially similar to the spacing between each adjacent
pair of support plate openings, and spacing between each adjacent
pair of second openings of the plurality of second openings may be
substantially similar to the spacing between each adjacent pair of
support plate openings.
[0030] Looking now at FIG. 5, an exploded top plan view of the
embodiment of FIG. 1 is shown wherein the spacings S.sub.L,S.sub.T
between each adjacent pair of parallel tubes 12 of the plurality of
parallel tubes 12 are substantially uniform and each tube 12 of the
plurality of tubes 12 has substantially the same outer diameter D.
The spacing between the centers of each adjacent pair of parallel
tubes 12 may be less than three times the outer diameter D of each
parallel tube and the outer diameter D of each parallel tube may be
less than or equal to one (1) mm. In an alternate embodiment of the
invention illustrated in FIG. 5A, spacings S.sub.L, S.sub.T between
each adjacent pair of parallel tubes of the plurality of parallel
tubes may be non-uniform. Optionally, spacing S.sub.L and/or
spacing S.sub.T may be uniform in a segment of the corrugated
pattern of the plurality of parallel tubes but non-uniform with
respect to another segment of the corrugated pattern. The spacing
between adjacent pairs of parallel tubes may be uniform in at least
one segment and non-uniform in at least one other segment along the
length of the corrugated pattern. The spacing of the parallel tubes
may be intentionally varied to control various fluid properties,
including the flow rate of the second fluid between the first and
second manifolds and between but outside of the parallel tubes in a
direction of flow which is generally perpendicular to the direction
of flow of the first fluid through the tubes. Spacing S.sub.L may
be greater than or less than spacing S.sub.T. Spacing S.sub.L
and/or spacing S.sub.T between each adjacent pair of parallel tubes
of the plurality of parallel tubes may be less than or equal to one
millimeter.
[0031] In at least one particular embodiment, as illustrated in
FIG. 3, the spacing between each adjacent pair of first openings of
the plurality of first openings is substantially equal to the
spacing between each adjacent pair of second openings of the
plurality of second openings.
[0032] Each of the first end portions of the parallel tubes is in
sealing relation to the first manifold so that each tube is in
fluid communication with a respective one of the first openings.
Similarly, each of the second end portions of the parallel tubes is
in sealing relation to the second manifold so that each tube is in
fluid communication with a respective one of the second openings.
The sealing relation between the tube end portions and their
respective manifolds may be formed by welding, gluing, braising, or
the like between the end portion of the tube and its respective
opening in the first or second manifold, as the case may be.
[0033] As noted earlier, in some embodiments of the invention, one
or more support plates may be disposed between the first and second
manifold. Support plate openings may vary in size from the first
and second openings. The plurality of substantially parallel tubes
may be attached to the support plate openings by gluing, welding,
braising, or the like. The plurality of substantially parallel
tubes also may be inserted through the support plate openings
without being fixably attached to the support plates. The
methodology employed to attach the plurality of substantially
parallel tubes to the support plates, if any, may vary depending
on, for example, the number of support plates disposed between the
first manifold and second manifold.
[0034] Manifolds and mid plates typically will be made of one or
more lamina of thin sheets, for example either metal or polymer,
each having the desired opening pattern. These lamina typically are
made via lithographic etching, or stamping, and either process can
produce the required lamina from a variety of metal alloys
including steel, nickel alloy, aluminum, titanium, or from a
polymer. Micro tubes typically may also be made from polymer or
metal alloys. Such metal alloys may include, e.g., steel, nickel
alloy, aluminum, or titanium. The manifold, midplates, and micro
tubes of the heat exchanger device can be made from the same
material or, for example, the device may comprise manifolds and
midplates made out of one material and micro tubes made from a
different material. The material used in making the heat exchanger
may be selected based on performance standards or physical
requirements. For example, the heat exchanger may be composed of
stainless steel in high temperature operations or environments
requiring high tensile strength. Aluminum may be chosen as a
suitable material in order to decrease the weight of the heat
exchanger. Such examples are nonlimiting and it should be apparent
that one of ordinary skill in the art may choose the heat exchanger
materials for a desired result based on the applicable factors.
[0035] Except as may be expressly otherwise indicated, the article
"a" or "an" if and as used herein is not intended to limit, and
should not be construed as limiting, the description or a claim to
a single element to which the article refers. Rather, the article
"a" or "an" if and as used herein is intended to cover one or more
such elements, unless the text expressly indicates otherwise.
[0036] This invention is susceptible to considerable variation
within the spirit and scope of the appended claims.
* * * * *