U.S. patent application number 10/430111 was filed with the patent office on 2004-01-01 for high performance fan tail heat exchanger.
Invention is credited to Tavassoli, Bahman.
Application Number | 20040000393 10/430111 |
Document ID | / |
Family ID | 22664964 |
Filed Date | 2004-01-01 |
United States Patent
Application |
20040000393 |
Kind Code |
A1 |
Tavassoli, Bahman |
January 1, 2004 |
High performance fan tail heat exchanger
Abstract
A novel plate fin heat exchanger adapted for high and low
velocity fluid flows for dissipating heat. The heat exchanger
comprises an array of fins being affixed to and in thermal
communication with a thermally conductive base, wherein the fins
are arranged in a fan tail configuration for minimizing flow
bypass, and further providing reduced thermal resistance for fluid
passing through the fin field. The fins are affixed to and in
thermal communication with the base at an acute angle, such that
the effective width of the array of fins exceeds the width of the
base. The enlarged effective width of the fin array in comparison
to conventional heat exchanger provides an increased volume for
fluid flow, thereby allowing a greater volume of fluid to enter the
fin field and a greater surface area of plate fins for cooling the
fluid passing through the heat exchanger.
Inventors: |
Tavassoli, Bahman; (Newton,
MA) |
Correspondence
Address: |
Rochelle Lieberman, Esquire
Lieberman & Brandsdorfer, LLC
12221 McDonald Chapel Drive
Gaithersburg
MD
20878
US
|
Family ID: |
22664964 |
Appl. No.: |
10/430111 |
Filed: |
May 6, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10430111 |
May 6, 2003 |
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10039391 |
Oct 29, 2001 |
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10039391 |
Oct 29, 2001 |
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09181598 |
Oct 29, 1998 |
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6308771 |
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Current U.S.
Class: |
165/80.3 ;
257/E23.099; 257/E23.103 |
Current CPC
Class: |
H01L 2924/00 20130101;
H01L 23/467 20130101; H01L 23/3672 20130101; F28F 2215/10 20130101;
F28F 3/02 20130101; H01L 2924/0002 20130101; H01L 2924/0002
20130101 |
Class at
Publication: |
165/80.3 |
International
Class: |
F28F 007/00 |
Claims
What is claimed:
1. A heat exchanger having a primary fin field that increases the
flow rate of fluid passing through said field and reduces thermal
resistance for fluid passing through a heat exchange field, said
heat exchanger dissipating heat from a heat generating component
and having a thermally conductive primary base in thermal
communication with said component, said primary base defining a
substantial planar region, a plurality of thermally conductive
plate fins affixed to said primary base in a spaced relationship
along said substantially planar region, said bottom of said fins is
affixed to said base at a straight angle, said plate fins defining
a primary fin field of channels, a top region, an intake region and
an exhaust region, and said plate fins having a uniform
cross-sectional area extending from the base to the top region;;
said plate fins forming a fan tail for providing a large control
volume of fluid passing through the heat exchanger and minimizing
fluid by-pass, wherein the width of the primary fin field adjacent
to the top region is greater than the width of the primary fin
field adjacent to the base; and said top region of said primary fin
field defining a flat planar surface area parallel to the planar
region of said base such that each fin in said primary fin field
extends from said base to said top region and each fin in said
primary fin field provides a uniform effective length for improving
convection.
2. The heat exchanger of claim 1, wherein said fin field has a
density range from about 10 fins per inch to about 60 fins per
inch.
3. The heat exchanger of claim 1, wherein the width of the fin
field has a range from about 45 mm to about 64 mm.
4. The heat exchanger of claim 1, wherein the length of the fins
range from about 15 mm to about 19.3 mm.
5. The heat exchanger of claim 1, wherein the angle of the fins to
the base range from about 51 degrees to about 90 degrees.
6. The heat exchanger of claim 1, wherein said fins have an
aperture along a common portion such that the aperture forms a
secondary channel perpendicular to the channels of the fin
field.
7. The heat exchanger of claim 1, wherein a set of end fins have a
thickness between 0.4 mm and 1.0 mm.
8. A heat exchanger comprising: a thermally conductive planar base;
plate fins affixed to said base and form a fin field; said fins
having generally uniform spacing between adjacent fins; a top
region of said fin field having a width greater than a width of a
bottom of said fin field adjacent to said base; and said top region
forms a planar surface area parallel to the base.
9. The heat exchanger of claim 8, wherein said fin field has a
density range from about 10 fins per inch to about 60 fins per
inch.
10. The heat exchanger of claim 8, wherein the width of the fin
field has a range from about 45 mm to about 64 mm.
11. The heat exchanger of claim 8, wherein the length of the fins
range from about 15 mm to about 19.3 mm.
12. The heat exchanger of claim 8, wherein the angle of the fins to
the base range from about 51 degrees to about 90 degrees.
13. The heat exchanger of claim 8, further comprising an aperture
along a common portion of said fins and to form a secondary channel
perpendicular to the channels of the fin field.
14. The heat exchanger of claim 8, wherein a set of end fins have a
thickness between 0.4 mm and 1.0 mm.
15. A heat exchanger comprising: a thermally conductive planar
base; plate fins affixed to said base and form a fin field; said
fins having generally equal spacing between adjacent fins; a top
region of said fin field having a width greater than a width of a
bottom of said fin field adjacent to said base; said plate fins
having a uniform cross-sectional area extending from the base to
the top region; and said top region forms a planar surface area
parallel to the base.
16. The heat exchanger of claim 15, wherein said fin field has a
density range from about 10 fins per inch to about 60 fins per
inch.
17. The heat exchanger of claim 15, wherein the width of the fin
field has a range from about 45 mm to about 64 mm.
18. The heat exchanger of claim 15, wherein the length of the fins
range from about 15 mm to about 19.3 mm.
19. The heat exchanger of claim 15, wherein the angle of the fins
to the base range from about 51 degrees to about 90 degrees.
20. The heat exchanger of claim 15, further comprising an aperture
along a common portion of said fins and to form a secondary channel
perpendicular to the channels of the fin field.
21. The heat exchanger of claim 15, wherein a set of end fins have
a thickness between 0.4 mm and 1.0 mm.
Description
CROSS REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a continuation of application Ser. No.
10/039,391, filed Oct. 29, 2001, now pending, which is a
continuation of application Ser. No. 09/181,598, filed Oct. 29,
1998, now U.S. Pat. No. 6,308,771, and hereby incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to an apparatus and method of cooling
a heat producing electronic component. More particularly, this
invention relates to a novel configuration and design for a heat
exchanger providing an apparatus and method for managing low
velocity fluid flow. The invention thereby expands the envelope of
cooling performance provided by fluid flow over plates.
[0004] 2. Discussion of Related Art
[0005] It is important to dissipate the heat produced by electrical
devices in order to extend the useful life of these devices. Heat
dissipation is particularly important in the case of high-power
electronic components, such as microprocessors and lasers, which
generate a relatively high amount of heat in a relatively small
area. Conventional heat sink devices typically utilize an array of
extended surfaces, such as fins, integrally formed on a common
base. The array of extended surfaces project into an ambient fluid
surrounding the device. The base is placed in thermal intimate
contact with a heat-producing device to provide a conduction path
to the fin array. Through forced or natural convection, fluid
circulation around the fin array acts as the heat transfer medium
for cooling the device to an operable temperature.
[0006] Designing acceptable heat exchangers to adequately dissipate
the heat generated by these heat generating components is a
difficult task. These electronic components are typically used
within systems housed in an enclosed cabinet having a fan mounted
therein. The fan is mounted so as to pull cooling fluid across the
heat generating electrical components. Given their relative
simplicity, traditional extruded plate fin heat exchangers are
generally preferred from both cost and implementation perspectives.
Traditional plate fin heat exchangers generally offer high surface
area relative to their size. However, the design of the
conventional plate fin heat exchanger is often inadequate for
dissipating heat generated from high power electronic components.
Accordingly, conventional plate fin heat exchangers with novel
design layouts for providing enhanced cooling of electronic
components are a preferred apparatus for providing the proper
cooling of the heat generating components.
[0007] Advances have been made involving the use of narrow channel
and micro-channel plate fin heat exchangers for cooling electronic
components. For example, U.S. Pat. No. 5,304,846 to Azar et al.,
discloses a narrow-channeled heat exchanger with certain geometric
relations aimed at improving the heat dissipation of the heat
exchanger. Specifically, the patent teaches optimal ratios relating
the height of the plate fins to the width of the channels. The
ratios may be selected for optimizing the heat dissipation
capabilities of the heat exchanger for a given pressure drop across
the heat exchanger.
[0008] Although narrow channel heat exchangers significantly
improve heat dissipation, they, like all other plate fin designs,
suffer from boundary layer formation. The boundary layer consists
of hydrodynamic and thermal layers which result from friction or
drag which occurs when the cooling fluid and the plate fins meet.
This boundary layer of hot low velocity fluid blankets the plate
fin heat exchanger insulating the exchanger from cooler fluid flow,
which causes a reduction in heat transfer and premature egress of
fluid from the fin field. In addition, the boundary layer narrows
the remaining channel available for fluid flow and causes a
reduction in the volume of the fluid flow, thereby significantly
reducing the productivity of the heat exchanger. Accordingly, the
conventional heat exchanger incorporating the narrow channel design
continues to suffer from a lower productivity due to the formation
of high pressure and a boundary layer.
[0009] The Assignee has a pending patent application Ser. No.
08/673,802, now U.S. Pat. No. 5,957,194, hereby incorporate by
reference, disclosing a heat exchanger comprising a fin field for
reducing formation of high pressure within the fin field,
increasing efficient heat transfer, and preventing premature egress
of fluid from the fin field. This particular heat exchange design
comprise fluid control and fluid ventilation designs for achieving
a reduction in high pressure fluid within the fin field. Although
the modifications disclosed in Assignee's pending application
successfully reduce the formation of high pressure and fluid
by-pass, such modifications to the individual fins can be costly
and difficult to manufacture. Applicant overcomes the formation of
high pressure and fluid by-pass through a novel design. The novel
fluid control and fluid ventilation elements of U.S. Pat. No.
5,957,194 may be incorporated into Applicant's invention to further
increase the performance of the heat exchanger within the
parameters of the present invention. Accordingly, the present
invention comprises a narrow channel fan tail heat exchanger for
alleviating the inefficiencies associated with prior art
conventional heat exchanger.
[0010] Therefore, what is desirable is a plate fin heat exchanger
that reduces and/or deters formation of high pressure, prevents the
premature egress of fluid from the fin field caused by formation of
high pressure, minimizes boundary layer formation without
increasing pressure, and enhances heat transfer. The present
invention incorporating a fan tail design together with a narrow
channel configuration overcomes the outstanding issues present in
the prior art and achieves the theoretical limit of cooling
performance provided by fluid flow over a plate fin heat
exchanger.
SUMMARY OF THE INVENTION
[0011] It is therefore the general object of the present invention
to provide a novel and improved plate fin heat exchanger for
dissipating heat from an electronic heat generating component.
[0012] It is a further object of the invention to provide a novel
heat exchanger adapted for optimum performance with low velocity
fluid flows for expanding the envelope of cooling performance from
fluid flow over plate fins. The novel design comprises a thermally
conductive plate in thermal communication with the heat generating
component, an array of thermally conductive plate fins affixed to
the base, wherein the plate fins define a fin field having
channels. The fins of the heat exchanger are designed to be affixed
to the base of the heat exchanger at an acute angle relative to the
base, such that the angle of the fin to the base is less than or
equal to ninety degrees and the effective width of the fin array
exceeds the width of the base.
[0013] It is even a further object of the invention to provide a
novel heat exchanger design wherein the fins are in thermal
communication with the base and affixed thereto such that the
effective width of the wing span of the fins exceeds the width of
the base. Commonly referred to as a fan tail, such an enlarged wing
span, when compared to conventional heat exchangers, provides an
increased control volume thereby allowing a greater volume of fluid
flow to enter the fin field.
[0014] In yet a further embodiment of the invention, the novel heat
exchanger comprises a fin density of at least ten fins per inch or
greater of base length thereby providing a narrow channel heat
exchanger with a fan tail. The aspect ratio of the individual
channels between the fins, as compared to parallel fins affixed
perpendicular to the base through an extrusion method, generates a
reduced pressure drop across the heat exchanger. Accordingly, the
fluid flow entering the heat exchanger is increased.
[0015] It is even a further object of the invention to provide a
novel heat exchanger comprising fins with surface modifications and
communication means. An increased surface area of the heat
exchanger is among the benefits associated with surface
modifications, such as undulations. In addition, the communication
means provides for a more effective cooling of the heat generating
component by the fluid passing through the heat exchanger.
[0016] In accordance with the invention, these and other objective
are achieved by providing a novel heat exchanger design and
configuration adapted for low velocity fluid flows. The invention
thereby expands the envelope of cooling capability of fluid flow
over a finned plate heat exchanger. Accordingly, the novel heat
exchanger provides for a heat exchanger comprising an array of fins
being affixed to and in thermal communication with a thermally
conductive base, wherein the fins are arranged in a fan tail
configuration for minimizing flow bypass, and further providing
reduced thermal resistance for fluid passing through the fin field
and a greater surface area of plate fins for cooling the heat
generating component by the fluid passing through the heat
exchanger.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] These and other objects, features and advantages of the
invention, as well as the invention itself, will become better
understood by reference to the following detailed description when
considered in connection with the accompanying drawings,
wherein:
[0018] FIG. 1 illustrates a side view of a prior art heat
exchanger;
[0019] FIG. 2 illustrates a top view of the prior art heat
exchanger of FIG. 1
[0020] FIG. 3 illustrates a perspective view of a preferred
embodiment of the heat exchanger of the present invention;
[0021] FIG. 4a illustrates a front view of a preferred embodiment
of the heat exchanger of the present invention;
[0022] FIG. 4b illustrates a top view of a preferred embodiment of
the heat exchanger of the present invention;
[0023] FIG. 5 illustrates a perspective view of an alternative
embodiment of the heat exchanger of the present invention; and
[0024] FIGS. 6 through 19 illustrates front views of the various
embodiments of the heat exchanger of the present invention;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS AND BEST MODE OF
THE INVENTION
[0025] In this disclosure, the term "fin" (also called a "plate" or
"flat fin") refers to a substantially planar heat exchanging member
that extends at an angle from a base. Such a base may support a
number of plate fins, in which case, "channels" are defined as the
spacing between adjacent fins. The area within and immediately
about the cluster of plate fins is referred to as the "fin field."
It should be understood that the term "fluid" as used herein refers
to both liquids and gases. The flow of fluid across the fin field
can be created using known means such as fans and natural
convection.
[0026] Referring now to the drawings, FIGS. 1 and 2 illustrate a
prior art configuration of a heat generating component 11 mounted
to a printed circuit board (PCB) 10 and adjacent to another PCB 24.
A prior art heat exchanger having individual plate fins 20 affixed
to a base 19 is mounted to the component 11. The plate fins 20
define a fin field 12, and channels 23 through which cooling fluid
13 flows. The fin field 12 has a top 18, and intake and exhaust
regions 16 and 15, respectively.
[0027] The combination of the heat generating component and the
heat exchanger form a three dimensional protrusion into the fluid
flow 14. The prior art heat exchanger, as illustrated in FIGS. 1
and 2, experiences certain fluid dynamics which reduce its
effectiveness, including high pressure formation at the upstream of
the heat exchanger, and premature fluid egress from the fin
field.
[0028] Cooling fluid 13 entering the fin field 12 through the
channels 23 forms a boundary layer 22 along the sides of the plate
fins 20 as shown in FIG. 2. The boundary layer is a region of
retarded fluid velocity that forms as a result of the friction
between the plate fins 20 and fluid. The layer tends to blanket the
plate fin thereby insulating it from the cooler fluid flow. This
reduces heat transfer. Additionally, the layer narrows the
remaining channel available to fluid flow which further impedes
fluid flow thus compounding the problem. As shown in FIG. 2, the
boundary layer 22 grows as the fluid 13 progresses down the
channel, eventually contributing to a region of near stagnant high
pressure fluid within the fin field.
[0029] Fluid not only penetrates the fin field 12 and forms
boundary layers, but also flows over and around it. Fluid flowing
over and around the fin field 12 is referred to as "flow by-pass"
in this disclosure. Flow by-pass typically reduces the efficiency
of the fin field 12. More specifically, fluid 21 flows around the
heat exchanger 12 (see FIG. 2), turns and enters it from the
exhaust region 15. This also contributes to the near stagnant, high
pressure region 17 within the fin field 12. This problem is
exacerbated because the by-pass fluid comprises relatively hot
fluid as the fluid travels around the fin field 12 in intimate
contact with the PCB. The PCB carries much of the heat generated by
the components mounted thereto, consequently the passing fluid is
heated as it passes the PCB. Accordingly, the increased flow
by-pass accompanying the traditional design of the heat exchanger
creates an increased temperature in the fluid flow surrounding the
heat exchanger, thereby limiting any secondary cooling of the fluid
adjacent to the PCB which otherwise may occur in the absence of a
fluid by-pass.
[0030] Additionally, the high pressure caused by the flow by-pass
and boundary layer formation impedes the fluid flow 13 through the
fin field 12 and contributes to its premature egress through the
field's top region 18. Consequently, relatively cool fluid entering
through the intake region 16 of the fin field 12 is prematurely
forced from the fin field. As such, the high pressure not only
blankets the region in a hot layer that retards efficient heat
transfer, but also forces the relatively cool fluid to leave the
fin field prematurely.
[0031] The present invention recognizes the physical attributes
which cause the formation of high pressure within the fin field and
its effects, as well as the formation of fluid bypass around the
fin field, and provides modifications to the conventional heat
exchanger as a means for providing a solution aimed at alleviating
and/or mitigating these effects and providing a more efficient heat
exchanger. In a preferred embodiment, the present invention
provides for an improved heat exchanger 30 designed for dissipating
heat from a heat generating component, such as a PCB. The heat
exchanger 30 of the present invention, as illustrated in FIG. 3,
comprises an array of thermally conductive plate fins 32 forming a
fin field 34 and affixed to or forming a thermally conductive base
35. Within this embodiment, the width of the fin field 34 comprises
a fan tail such that the span of the fins is greater than the width
of the base. The plate fins define a fin field having channels 36,
a top region 37, sides 38, an intake region 39 and an exhaust
region 31. The thickness of the individual fins may range from
about 0.1 mm to about 0.5 mm. Accordingly, the novel heat exchanger
of the present invention provides for a fan tail configuration with
the effective width of the heat exchanger exceeding the width of
the base 35, together with an increased fin density along the width
of the base to deter the formation of high pressure within the fin
field, reduce the premature egress of fluid from the top region 37
of the fin field 34, minimize boundary layer formation and fluid
bypass, and minimize fluid entering from the exhaust region.
[0032] Among the benefits associated with the novel design of the
heat exchanger illustrated in FIG. 3 is the increase of the flow
rate of the fluid passing through the fin field. By spreading the
angle of the fins in the fin field, the mass flow rate of the fluid
passing through the fin field increases because there is less
resistance to the fluid flow. In addition, the wider flow entrance
provides a larger control volume wherein more fluid may enter the
fin field as compared to a conventional heat exchanger with the
same or similar base geometry, fin length, and number of fins laid
across and perpendicular to the base. As such, the unique
configuration of the angled fins reduces the resistance on the
fluid flow thereby maintaining the fluid within the fin field while
allowing the fluid to pass through the fin field 34 to the exhaust
region 31 of the heat exchanger 30. In addition to the fan tail
configuration of the heat exchanger 30 of FIG. 3, the novel design
comprises a density of at least ten fins per inch of base and may
attain a density of at least as high as sixty fins per inch.
[0033] The increased density of the fins in view of conventional
heat exchangers manufactured through an extrusion method in
combination with the fan tail design provides a novel heat
exchanger with improvements over the prior art. As illustrated in
FIG. 3, the fluid enters the fin field 34 at an intake region 39 of
the heat exchanger 30. Due to the configuration of the fin field 34
providing a reduced resistance to the fluid flow, the fluid
egresses the fin field 34 through the exhaust region 31 of the heat
exchanger 30. In addition, while the fluid is passing through the
heat exchanger 30, most of the fluid is maintained in the fin field
34. By maintaining the fluid in the fin field, and egressing the
fluid through the exhaust region 31 of the heat exchanger 30, both
the fluid bypass as well as formation of high pressure in regions
surrounding the heat exchanger are significantly reduced.
Accordingly, the heat exchanger illustrated in FIG. 3 provides a
novel design for a more efficient cooling process.
[0034] FIGS. 4a and 4b are an illustration of one example of the
heat exchanger of the present invention. In FIGS. 4a and 4b, each
of the fins 42 in the fin field 44 extends from the base 45 at an
angle .alpha., ranging from 51.degree. to 90.degree.. The fin with
the sharpest angle is the outermost fin 47, as shown in FIG. 4a. As
the fins approach the center of the base 45, the central fin may
have an angle of 90.degree.. The length of each of the fins 42 vary
according to the angle and positioning of the fin relative to the
base 45 so that the effective height of each of the fins is
uniform. In the illustrated heat exchanger 40 of FIGS. 4a and 4b,
the effective height of the heat exchanger is 15 mm, with the
length of the fins ranging from 19.3 mm to 15 mm in the center. The
width of the base is 45 mm, however, the effective width of the
heat exchanger with the increased wing span is 64 mm. In this
particular example, the spacing between the adjacent fins in the
fin field at the point where the fins attach or secure to the base
is 2.0 mm. However, the spacing between adjacent fins at the top of
the fin field is approximately 4.0 mm. As such, the spacing between
the fins increases as the distance from the base to the top of the
fin field increases. The spacing between the fins in FIGS. 4a and
4b is an example of the larger spacing between the fins in the
field as compared to a conventional heat exchanger. The spacing
between the fins along the base 45 ranges from about ten fins per
inch to about forty fins per inch as laid out across the length of
the base. As mentioned above, this spacing reduces premature egress
of incoming fluid and thereby mitigating the amount of fluid flow
exiting the fin field in an upward direction through the top
region. Accordingly, the spacing between the fins 42 together with
the angle .alpha. at which the fins are attached to the base 45
provides for the increased fan tail of the fin field so as to
provide less resistance to the fluid flow through the fin
field.
[0035] The configuration of the heat exchanger 40 illustrated in
FIGS. 4a and 4b is one example of a heat exchanger with an
increased fan tail exceeding the width of the base. The combination
of the fan tail together with the fin density along the width of
the base allows the heat exchanger to provide for smaller aspect
ratios of individual channels between the fins as compared with the
prior art and causes a smaller pressure drop to be generated across
the heat exchanger. The smaller pressure drop across the heat
exchanger 40 in FIGS. 4a and 4b increases the velocity of the fluid
upstream of the entrance region. Accordingly, the increased fluid
flow associated with the novel design together with the smaller
pressure drop minimizes the fluid bypass commonly found in a
conventional heat exchanger.
[0036] In addition to the novel design disclosed in FIG. 3, the
invention also includes variations to the design which include
means for further increasing the fluid flow under varying
environmental conditions. Referring to FIGS. 5 through 19, specific
alternative embodiments of the novel heat exchanger of the present
invention are illustrated in light of the above-discussed
principles. These embodiments depict various configurations of the
mounting of an array of fins. The multiple configurations
illustrated and discussed below each work to provide a heat
exchanger comprising heat transfer of the fluid flow through the
heat exchanger so as to minimize boundary layer formation, deter
formation of high pressure, and reduce premature egress of fluid
from the fin field. It is noted that each of the individual fin
members disclosed in the various embodiments may be interchanged
and varied to form an infinite number of configurations for a fan
tail heat exchanger. Additionally, for purposes of simplicity some
of the remaining drawing figures disclose features present on one
half section of the heat exchanger being discussed. The illustrated
heat exchanger actually incorporates the representative section
onto the non-illustrated section of the heat exchanger in a mirror
image layout. Furthermore, the scope of the invention should not be
limited to the specific configuration of each heat exchanger
illustrated in the attached drawing figures. Rather, the fins of
each illustrated heat exchanger may be arranged and or combined
with apertures, undulations, perpendicular channels, multiple fin
lengths, secondary bases, wherein each configuration provides for a
fan tail heat exchanger and the heat transfer benefits associated
therewith. Accordingly, the heat exchangers illustrated in FIGS. 5
through 19 are best described as alternating half segments of a
complete heat exchanger such that the half segment depicted in each
figure can be combined with a similar half segment or any of the
alternative half segments depicted in the other figures to compose
a complete heat exchanger.
[0037] Furthermore, although the attached figures illustrate the
base of the formed heat exchanger as being a horizontal planar
surface, the base may be formed in a variety of shapes and
positions. For example, a heat exchanger base may be circular in
shape, thereby allowing the formed heat exchanger to be fitted
around a circular object or fixture. Again, the non-planar shape of
a heat exchanger should not be considered to be limited to a
circular shape, rather the non-planar shape of a heat exchanger may
be manufactured in a variety of shapes and sizes according to the
desired result. Accordingly, both planar and non-planar heat
exchanger may be formed in conjunction with the novel features
described herein.
[0038] FIG. 5 is an illustration of a fan tail heat exchanger 50
comprising several distinct and novel modifications to the heat
exchanger 30 of FIG. 3. In FIG. 5, the displacement of the fins in
relation to the base may be equivalent to that of FIG. 3, however,
the fins comprise an aperture 58 at approximately the midsection of
each fin in the array. The apertures 58 in each fin align, so that
they form a channel 56 perpendicular to the parallel channels
between the adjacent fins. Such a channel 56 provides greater ease
in mounting the heat exchanger 50 to a heat dissipating component.
Accordingly, the channel 56 provides additional and alternative
means of mounting a heat exchanger.
[0039] As shown in FIGS. 3 and 5, each fin has a uniform
cross-sectional area along the entire length of the fin extending
from the base to the top region. The point where the individual
fins meet the base is a straight angle without any rounded corners.
In addition, the heat exchanger 50 of FIG. 5 also comprises a set
of end fins 57 having differing characteristics to the remaining
fins 52 mounted on the base 55. The end fins 57 in this embodiment
comprise a thickness significantly greater than the thickness of
the fins therebetween. The thickness of the end fins may range from
about 0.4 mm to about 1.0 mm. Among the benefits associated with
end fins of this configuration is the ability of an individual or a
mechanical apparatus to handle the heat exchanger with a reduced
risk of damage. In general, the fins of the heat exchanger are
relatively thin and are exposed to being damaged during handling as
their resulting flexibility would allow for their distortion during
handling. Accordingly, by providing end fins with a greater
thickness and durability, the heat exchanger 50 is less fragile and
more manageable.
[0040] The novel design of the heat exchanger 50 of FIG. 5 is not
limited to the specific mounting structure of the fins 52 to the
base 55 nor to the specific dimensions and sizings disclosed.
Rather, this unique design of a fan tail heat exchanger 50,
together with the perpendicular channel 56 and/or the increased
thickness of the end fins 57 in comparison to the interior fins 52,
may be combined with any of the novel heat exchangers disclosed
herein to form a novel heat exchanger with the beneficial
properties described herein.
[0041] FIG. 6 illustrates a heat exchanger 60 comprising an array
of plate fins mounted to the base 65 such that several of the
interior plate fins 68 and 69 are mounted to the base at or near a
90 degree angle, and several of the exterior fins 66 and 67 are
mounted to the base at an acute angle. The interior fins 68 and 69
comprises a uniform effective length, whereas the exterior fins 66
and 67 do not comprise a uniform effective length. As shown in FIG.
6, the length of the exterior fins 66 and 67 decrease as they
extend toward the edge of the base 65. Due to the mounting of the
exterior fins 66 and 67, the heat exchanger 60 of this
configuration comprises the fan tail characteristics. Among the
benefits associated with this configuration is a high fin density
for low to moderate fluid flow. The exterior fins 66 and 67
adjacent to an exterior edge of the base 65 are shorter than the
interior fins 68 and 69 and function to guide the fluid flow closer
to the component edge. Accordingly the design of this embodiment
provides for a fin assembly for reducing or minimizing flow
dispersion from the vicinity of the heat exchanger.
[0042] FIG. 7 illustrates a heat exchanger 70 comprising an array
of plate fins being mounted to the base 75 such that the
relationship of the angles of the exterior fins to the base 75 is
uniform, but the effective length of the exterior fins are not
uniform. As clearly illustrated, the end fin 76 is approximately
twice the length of the adjacent fin 77. The length of the third
fin 78 is equivalent to the length of the second fin, however, the
length of the fourth fin 79 is equivalent to the length of the
first fin 76. As such, the fins are mounted to the base in a
specific pattern within a fan tail configuration. This particular
design is beneficial for natural convection fluid flows. The end
fin 76 together with the fourth and seventh fins, 79 and 71
respectively, essentially create the channeled fluid flow, while
providing the required fluid flow for the short fins 77 and 78 that
function to dissipate the heat from the heat generating
component.
[0043] FIG. 8 illustrates a heat exchanger 80 comprising an array
of plate fins mounted to the base 85 such that the relationship of
the angles of the exterior fins to the base 85 is uniform, but the
length of the fins are not uniform. As clearly illustrated, the
fins are mounted in sets of four, where the end fin 86 is the
longest, and the length of the next three fins 87, 88, and 89 are
successively shorter. The sets of fins are mounted to the base 85
in a pattern which repeats along the length of the base. Similar to
the design disclosed in FIG. 7, this particular design is ideal for
natural convection fluid flows. The end fins 86 together with the
other long length fins 81 essentially create the channeled fluid
flow, while providing the required fluid flow for the successively
shorter fins 87, 88 and 89 that function to increase heat
dissipation from the heat generating component. Accordingly, the
relation between the height of the fins 86, 87, 88 and 89 function
to enhance heat transfer.
[0044] FIG. 9 is an illustration of a heat exchanger 90 comprising
a reverse layout design from that of the heat exchanger 70
disclosed in FIG. 7. In FIG. 9, an array of plate fins are mounted
to a base 95 where the relationship of the angles of the exterior
fins to the base 95 is uniform, but the effective length of the
fins are not uniform. The two exterior most fins 96 and 97 are
short followed by a tall fin 98, and then the pattern and layout of
the fins repeat. This particular design provides a similar function
to the heat exchanger 70 of FIG. 7. The exterior fins 96 and 97
help minimize flow dispersion around the heat sink and also provide
a higher speed fluid flow through the exhaust end of the heat
exchanger 90. Again, the combination of the short fins 96 and 97
together with the tall fins 98 makes the heat exchanger ideal for
natural convection fluid flow. The tall fins 98 create the
channeled fluid flow thereby providing the required fluid flow for
the shorter fins 96 and 97 for heat dissipation. Accordingly, the
configuration of FIG. 9 provides a channeled fluid flow while
minimizing flow dispersion around the heat exchanger and providing
higher velocity fluid flow at the exhaust region.
[0045] FIG. 10 is an illustration of a heat exchanger 100
comprising an inverse fin configuration of the heat exchanger 80
disclosed in FIG. 8. In FIG. 100, the shortest fin 106 is mounted
at the outermost portion of the base 105. The fins increase in
length along the base 105 towards the interior portion of the base,
until the pattern of the fin configuration repeats. The shorter
fins 106, 107 and 108 mounted along the exterior portion of the
base 105 provide a minimized fluid flow dispersion and a higher
velocity fluid flow at the exhaust region of the heat exchanger
100. Accordingly, the design of this heat exchanger 100 is
beneficial where higher velocity fluid flows are desirable.
[0046] FIG. 11 discloses a heat exchanger 110 of the present
invention comprising communication, ventilation and fluid control
means together with the fan tail exceeding that of the width of the
base 115. In FIG. 11, the fins 117, 118 and 119 are not flat,
rather they comprise undulations along the length of the fin.
Although the surface modifications in FIG. 11 are in the form of
undulations, the surface modifications may also include notches,
apertures, slots, flow guides and comparable design features. Such
surface modifications provide a means for increasing the surface
area of the fins in the heat exchanger while also providing an
increase fan tail for the heat exchanger as a whole. In addition,
the surface modifications provide for enhanced heat transfer by
reducing the boundary layer and managing the flow distribution in
the fin field. Accordingly, the combination of surface
modifications on the individual fins 117, 118 and 119 together with
the fan tail design results in a heat exchanger with a lower
thermal resistance.
[0047] FIG. 12 discloses a heat exchanger 120 of the present
invention comprising a mounted fin field 122 similar to the heat
exchanger 70 of FIG. 7. The exterior fin 126 is the longest fin in
the fin field and, as the fins progress toward the midsection of
the heat exchanger 120, they decrease in height sequentially in
sets of three. As such, the fin 127 adjacent to the exterior fin
126 has a medium height and is shorter than the exterior fin 126,
while the next sequential fin 128 is the shortest in height among
the fins mounted to the base. Adjacent to the shortest fin 128 is
another set of fins 128a, 127a and 126a arranged in a mirror image
to the first three fins 126, 127 and 128. As such, the pattern of
fins repeat once toward the midsection of the base 125. The
secondary set of fins 124 adjacent to the midsection of the base
125 provide for a higher velocity flow as compared to the primary
set of fins 123 adjacent to the exterior edge of the base 125.
Accordingly, the configuration of the fins in relation to their
lengths makes this heat exchanger 120 desirable in instances where
low velocity fluid flows are sought.
[0048] FIG. 13 discloses a heat exchanger 130 of the present
invention comprising a plurality of fins mounted to the base 135 at
a mixture of angles. As illustrated in FIG. 130, the first fin 136,
the second fin 137 , and the third fin 138 each extend angularly
toward the exterior portion of the base 135. The displacement of
the fins 136, 137 and 138 provide the fan tail configuration for
the heat exchanger 130. The first two fins 136 and 137 are short in
length and the third fin 138 is tall. It should be noted that the
fin configuration of the remaining portions of the first section of
the heat exchanger 130 do not repeat in an identical manner as in
the previous illustrations of the various embodiments present.
Rather, as illustrated in FIG. 13, the sequential fins 136a and
137a, adjacent to the third fin 138, are short in length, similar
to the first and second fins 136 and 137 respectively, however the
sequential fins extend at an acute angle toward the center of the
heat exchanger 130. The following fin 139 is a tall fin, similar if
not equal in length to the third fin 138. The tall fin 139 extends
at an acute angle toward the exterior portion of the heat exchanger
130. Each of the tall fins present 138 and 139 in this embodiment,
with exception of the central fin 132, extend toward the exterior
portion of the heat exchanger similar to the first, second, and
third fins 136, 137 and 138. Among the benefits associated with
this fin field layout is that the short sets of fins mounted at
opposite angles assist in breaking the boundary layer and the
subsequent stagnation points in the aggregate fin field adjacent to
the base 135. Accordingly, the heat exchanger of FIG. 13 provides a
lower thermal resistance than prior art heat exchangers.
[0049] The heat exchanger 140 illustrated in FIG. 14 is a
modification to the heat exchanger 130 of FIG. 13. As illustrated
in FIG. 14, the fin field of this heat exchanger 140 comprises two
significant modifications, first the fin field density is increased
and second the shorter set of fins 142, 143 and 144 comprise
varying lengths. The first and second fins 146 and 147 are nearly
identical in length and extend angularly toward the exterior
portion of the base 145. The third fin 148 is long, and similar to
the first two fins, 146 and 147, extends at a similar angle toward
the exterior portion of the base 145. Each of the tall fins present
in this embodiment extend angularly toward the exterior portion of
the heat exchanger, similar to the first two fins 146 and 147.
However, the short interior set of fins 143 and 144 extend at an
acute angle toward the center of the fin, in a direction opposite
to the first two fins 146 and 147, as well as the tall fins 148.
Accordingly, the heat exchanger 140 of FIG. 14 enhances the fluid
flow and manages the flow distribution in the fin field while
providing a reduced thermal resistance.
[0050] FIG. 15 discloses a heat exchanger 150 of the present
invention comprising a plurality of secondary heat exchangers 151,
152 and 153 mounted within the heat exchanger 150. As illustrated,
the heat exchanger 150 comprises a primary base 155 and a primary
fin field 154. However, within the primary fin field 154, the heat
exchanger comprises a set of secondary bases 151a, 152a and 153a
mounted to the primary base 155. The thickness of the individual
secondary bases may range from about 0.5 mm to about 1.5 mm. In a
preferred embodiment, the secondary bases 151a, 152a and 153a are
mounted orthogonally to the primary base. However, in an
alternative embodiment, the secondary bases 151a, 152a, 153a may be
mounted to the primary base at any angle, so long as the primary
and secondary bases remain in thermal communication. In addition,
the secondary bases should not be limited to the structure
disclosed in the referenced drawing figures, rather the secondary
base may be circular in shape or may comprises a variety of
non-planar shapes. The secondary bases 151a, 152a and 153a each
have a secondary fin field 151b mounted orthogonal or angled
therefrom. In a further embodiment, as illustrated in FIG. 16, the
secondary bases 161, 162 and 163 may have two sets of fin fields
161a and 162b, 162a and 162b, and 163a and 163b extending outwardly
from both sides of the secondary bases 161, 162 and 163. In
general, the secondary bases of both FIGS. 15 and 16 function to
transfer a large portion of the heat from the primary bases 155 and
165. The secondary fin fields work with the secondary bases and
provide extended surfaces for dissipating heat within the heat
exchanger. Based upon the configuration of the heat exchangers 150
and 160, the secondary fin fields are offset mounted from the
primary bases 155 and 165 and as such reside in a cooler fluid
environment than a conventional fin field heat exchanger wherein
the fin field is mounted adjacent to the primary base. Accordingly,
the heat exchanger enhances heat transfer of cooler fluid adjacent
to the top of the fin field, wherein the net effect of utilizing
the heat exchanger is a net increase in the rate of thermal
reduction.
[0051] FIG. 17 is an illustration of a heat exchanger 170
comprising an alternative embodiment to the heat exchangers 150 and
160 of FIGS. 15 and 16. The heat exchanger 170 comprises a set of
fins 177 mounted to the primary base 175 between the set of
secondary bases 171, 172 and 173. The fins 177 provide a higher
performance heat exchanger and a means for enhancing heat transfer
between the hotter fluid adjacent to the primary base 175 and the
cooler fluid lying at the top of the fin field.
[0052] FIG. 18 is an illustration of a heat exchanger 180
essentially comprising two primary sets of fin fields 181 and 182
having a fan tail. The heat exchanger 180 combines the heat
exchanger 60 of FIG. 6 and repeats the pattern along the base 185.
The pattern may be repeated two or three times depending upon the
length of the base and the fin density. Among the benefits
associated with this heat exchanger 180 is that it creates
significantly higher fluid velocity at the center of the fin field
where the heat source tends to be concentrated.
[0053] In an alternative embodiment, as illustrated in FIG. 19, the
fin field comprises a set of secondary fins 197 mounted
perpendicular to the base between the two primary fin fields 191
and 192, respectively. The secondary set of fins 197 increases the
performance of the heat exchanger 190 and provides for a greater
heat transfer between the hotter fluid adjacent to the base 195 and
the cooler fluid located at an area adjacent to the top of the fin
field. The scope of the heat exchange of this embodiment should not
be limited to the drawing figure illustrated. The secondary fin
field 197 may vary in density depending upon the desired level of
performance. Accordingly, the primary embodiments of the heat
exchanger 190 of FIG. 19 disclose the combination of the plurality
of primary fan tail fin fields together with a secondary fin field
mounted there between for enhancing performance of the heat
exchanger 190.
[0054] The above description is of a novel heat exchanger and
method for improving the flow of fluid and heat transfer of fluid
adjacent to a heat generating component. Although the present
invention has been described in connection with preferred
embodiments thereof, it will be appreciated by those skilled in the
art that additions, deletions, modifications, and substitutions not
specifically described may be made without departing from the
spirit and scope of the invention as defined in the appended claims
and the scope should not be limited to the dimensions indicated
herein above.
* * * * *