U.S. patent application number 13/046597 was filed with the patent office on 2012-09-13 for aerodynamic heat exchange structure.
Invention is credited to Gary Schwartz, Richard M. Weber.
Application Number | 20120227949 13/046597 |
Document ID | / |
Family ID | 46794466 |
Filed Date | 2012-09-13 |
United States Patent
Application |
20120227949 |
Kind Code |
A1 |
Weber; Richard M. ; et
al. |
September 13, 2012 |
AERODYNAMIC HEAT EXCHANGE STRUCTURE
Abstract
The present invention relates to heat exchangers, and more
particularly to a heat exchange structure configured to operate in
an air stream. In one embodiment, a heat exchange structure
configured to operate in an air stream includes coolant flow
portions, each of the coolant flow portions having at least one
substantially closed surface directed into the air stream; and air
flow portions disposed between adjacent coolant flow portions for
receiving air from the air stream, the air flow portions having air
passages directed into the air stream; the substantially closed
surface of the coolant flow portions having an aerodynamic
shape.
Inventors: |
Weber; Richard M.; (Prosper,
TX) ; Schwartz; Gary; (Dallas, TX) |
Family ID: |
46794466 |
Appl. No.: |
13/046597 |
Filed: |
March 11, 2011 |
Current U.S.
Class: |
165/185 ;
29/890.03 |
Current CPC
Class: |
F28D 9/0062 20130101;
F28F 2250/02 20130101; Y10T 29/4935 20150115 |
Class at
Publication: |
165/185 ;
29/890.03 |
International
Class: |
F28F 7/00 20060101
F28F007/00; B21D 53/02 20060101 B21D053/02 |
Claims
1. A heat exchange structure configured to operate in an air
stream, the heat exchange structure comprising: coolant flow
portions, each of the coolant flow portions having at least one
substantially closed surface directed into the air stream; and air
flow portions disposed between adjacent coolant flow portions for
receiving air from the air stream, the air flow portions having air
passages directed into the air stream; the substantially closed
surface of the coolant flow portions having an aerodynamic
shape.
2. The heat exchange structure of claim 1, wherein the
substantially closed surface is at a leading edge of the coolant
flow portions directed into the air stream.
3. The heat exchange structure of claim 2, wherein the
substantially closed surface has a shape that is convex into the
air stream.
4. The heat exchange structure of claim 2, wherein each coolant
flow portion has a trailing edge at an end of the coolant flow
portion opposite the leading edge.
5. The heat exchange structure of claim 4, wherein the trailing
edge has a shape that is tapered rearwardly away from the leading
edge.
6. The heat exchange structure of claim 1, wherein the heat
exchange structure is configured in a free air stream.
7. The heat exchange structure of claim 1, wherein the heat
exchange structure is configured in an air duct.
8. The heat exchange structure of claim 1, wherein the heat
exchange structure is configured in an air plenum.
9. A method of manufacturing a heat exchange structure configured
to operate in an air stream, comprising: providing coolant flow
portions, each of the coolant flow portions having at least one
substantially closed surface; arranging the coolant flow portions
such that the substantially closed surface is directed into the air
stream; providing air flow portions between adjacent coolant flow
portions, the air flow portions having air passages for receiving
air from the air stream; arranging the air flow portions such that
the air passages are directed into the air stream; and configuring
the substantially closed surface of the coolant flow portions to
have an aerodynamic shape.
10. The method of claim 9, wherein configuring the substantially
closed surface of the coolant flow portions to have an aerodynamic
shape further comprises designing the aerodynamic shape to be
convex into the air stream.
11. The method of claim 10, further comprising designing each of
the coolant flow portions to have a trailing edge at an end
opposite the substantially closed surface, wherein the trailing
edge has a shape that is tapered rearwardly away from the
substantially closed surface.
Description
FIELD
[0001] The present invention relates to heat exchangers, and more
particularly to a heat exchange structure configured to operate in
an air stream.
BACKGROUND
[0002] Heat exchangers are devices used transfer heat from one
medium to another. For example, in a heat exchanger, air may flow
over a coil carrying hot engine coolant, and heat from the coil may
be released into the air. Common applications for heat exchangers
include air conditioning, refrigeration, space heating, power
plants, chemical plants, sewage treatment, and car radiators.
[0003] Heat exchangers come in many forms, and can have different
structures depending on the heat load to be transferred and the
environment in which the heat exchanger is used. Efficient heat
exchangers are able to transfer large amounts of heat from one
medium to another. Typical heat exchange structures have surfaces
such as walls separating heat transfer fluids from one another.
[0004] The flow paths of the heat transfer fluids can be arranged
in various ways. Some heat exchangers have channels that carry the
heat transfer fluids in two different directions that are
substantially perpendicular to one another. For example, as shown
in FIG. 1, a typical heat exchange structure 10 may have a
plurality of air flow portions 12 disposed between a plurality of
coolant flow portions 16. Air from the air stream 14 enters and
exits the heat exchange structure 10 through the air flow portions
12, and the coolant fluid 18 enters and exits the heat exchange
structure 10 in a substantially perpendicular direction through the
coolant flow portions 16. Thus, coolant fluid 18 flows in one
direction through the coolant flow portions 16, and air from the
air stream 14 flows through the air flow portions 12 in a second
direction that is substantially perpendicular to the coolant flow
direction.
[0005] The coolant flow portions 16 have closed surfaces 17 that
are broadside to the air stream 14, so that the coolant fluid 18
can flow through the coolant flow portions 16 in a direction
perpendicular to the flow of the air stream 14. In typical heat
exchangers, the closed surfaces 17 are blunt, flat-faced surfaces.
As a result, when the air stream 14 enters the air flow portions
12, the air experiences a pressure drop due to flow separation
occurring at the blunt closed surfaces 17 of the coolant flow
portions 16. Therefore, typical heat exchangers may be inefficient
for operation in an air stream, because the pressure of the air
entering the heat exchanger may be reduced.
[0006] Accordingly, there is a need for a heat exchange structure
that can transition air through a heat exchanger with less pressure
drop.
SUMMARY
[0007] The present invention relates to heat exchangers, and more
particularly to a heat exchange structure configured to operate in
an air stream. The efficiency of a heat exchanger can be improved
by decreasing the resistance to fluid flow through the heat
exchanger. In one embodiment, a heat exchange structure includes
coolant flow portions having a substantially closed surface
directed into an air stream, and air flow portions having air
passages directed into the air stream. The substantially closed
surfaces of the coolant flow portions have aerodynamic shapes at
their leading edges. The aerodynamic shapes of the closed surfaces
facilitate the flow of air through the air flow portions and
decrease the pressure drop of the air flowing through the heat
exchanger.
[0008] In one embodiment, a heat exchange structure configured to
operate in an air stream includes coolant flow portions, each of
the coolant flow portions having at least one substantially closed
surface directed into the air stream; and air flow portions
disposed between adjacent coolant flow portions for receiving air
from the air stream, the air flow portions having air passages
directed into the air stream; the substantially closed surface of
the coolant flow portions having an aerodynamic shape.
[0009] The substantially closed surface may be at a leading edge of
the coolant flow portions directed into the air stream. The
substantially closed surface may have a shape that is convex into
the air stream. Each coolant flow portion may have a trailing edge
at an end of the coolant flow portion opposite the leading edge.
The trailing edge may have a shape that is tapered rearwardly away
from the leading edge.
[0010] The heat exchange structure may be configured in a free air
stream, in an air duct, or in an air plenum.
[0011] In another embodiment, a method of manufacturing a heat
exchange structure configured to operate in an air stream includes
providing coolant flow portions, each of the coolant flow portions
having at least one substantially closed surface; arranging the
coolant flow portions such that the substantially closed surface is
directed into the air stream; providing air flow portions between
adjacent coolant flow portions, the air flow portions having air
passages for receiving air from the air stream; arranging the air
flow portions such that the air passages are directed into the air
stream; and configuring the substantially closed surface of the
coolant flow portions to have an aerodynamic shape.
[0012] The step of configuring the substantially closed surface of
the coolant flow portions to have an aerodynamic shape may further
include designing the aerodynamic shape to be convex into the air
stream. The method of manufacturing the heat exchange structure may
further include designing each of the coolant flow portions to have
a trailing edge at an end opposite the substantially closed
surface, wherein the trailing edge has a shape that is tapered
rearwardly away from the substantially closed surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows a typical heat exchange structure.
[0014] FIG. 2 shows a profile of coolant flow portions of a heat
exchange structure according to an embodiment of the present
invention.
[0015] FIG. 3 shows a profile of coolant flow portions of a heat
exchange structure according to another embodiment of the present
invention.
[0016] FIGS. 4A and 4B show profiles of coolant flow portions of a
heat exchange structure according to another embodiment of the
present invention.
DETAILED DESCRIPTION
[0017] The present invention relates to heat exchangers, and more
particularly to a heat exchange structure configured to operate in
an air stream. The efficiency of a heat exchanger can be improved
by decreasing the resistance to fluid flow through the heat
exchanger. In one embodiment, a heat exchange structure includes
coolant flow portions having a substantially closed surface
directed into an air stream, and air flow portions having air
passages directed into the air stream. The substantially closed
surfaces of the coolant flow portions have aerodynamic shapes at
their leading edges. The aerodynamic shapes of the closed surfaces
facilitate the flow of air through the air flow portions and
decrease the pressure drop of the air flowing through the heat
exchanger.
[0018] FIG. 2 shows a profile of coolant flow portions of a heat
exchange structure according to an embodiment of the present
invention. Coolant fluid flows into the coolant flow portions 26 in
a direction perpendicular to the air stream 24. For example, in
FIG. 2 coolant fluid flows in a direction that is normal to the
surface of the page. Adjacent coolant flow portions 26 define air
flow portions 22 therebetween. The air flow portions 22 have air
passages for air stream 24 to flow through the heat exchange
structure 20. Each coolant flow portion 26 has a leading edge
facing upstream at the entrance to an adjacent air flow portion 22,
and a trailing edge on the downstream at an exit of the adjacent
air flow portion 22. The coolant flow portions 26 may be
constructed of any material suitable for heat transfer, such as
aluminum fin stock.
[0019] As shown in FIG. 2, in one embodiment each coolant flow
portion 26 has an additional shape 23 at a leading edge of the
coolant flow portion 26. The shape 23 is pointed and tapered in an
upstream direction. Each coolant flow portion 26 also has an
additional shape 25 opposite the shape 23 at a trailing edge of the
coolant flow portion 26, which is also pointed and is tapered in a
downstream direction. That is, the shape 25 is tapered rearwardly
away from (or relative to) the leading edge. The coolant flow
portions 26 having additional shapes 23 and 25 at their leading and
trailing edges, respectively, improve the flow of air through the
air flow portions 22. The air flow through the heat exchange
structure 20 is improved over the air flow through the heat
exchange structure 10 shown in FIG. 1, because the added
aerodynamic shapes reduce or eliminate the pressure drop
experienced at the blunt closed surfaces 17.
[0020] In other words, in FIG. 2, air from the air stream 24 clings
to the aerodynamic shapes 23 at the entrances of the air flow
portions 22 such that the air is more easily pulled in, and
therefore the air flow is not separated by blunt, flat-faced
surfaces as in FIG. 1. Accordingly, the additional shapes 23 at the
leading edges of the coolant flow portions 26 reduce the pressure
drop encountered at the entrance to the air flow portions 22.
Further, the aerodynamic shapes 25 at the trailing edges of the
coolant flow portions 26 produce a companion decrease in the air
pressure at the exit to the air flow portions 22. The pointed,
tapered shape 25 of the trailing edge can provide a greater
decrease in the air pressure at the exit than can the blunt
trailing edges of the coolant flow portions 16 in FIG. 1. The
resulting increase in a differential pressure between the entrance
and exit to the air flow portions 22 improves the flow of air
through the heat exchange structure 20.
[0021] The additional shapes 23 and 25 also increase the available
surface area for heat transfer along the leading and trailing edges
of the coolant flow portions 26. As a result, the coolant flow
portions 26 in FIG. 2 have a higher heat transfer coefficient than
the coolant flow portions 16 in FIG. 1. Therefore, a heat exchange
structure according to the embodiment of FIG. 2 may have improved
heat transfer efficiency.
[0022] FIG. 3 shows a profile of coolant flow portions of a heat
exchange structure according to another embodiment of the present
invention. In the embodiment shown in FIG. 3, each of the coolant
flow portions 36 is formed in an elliptical shape. A rounded shape
33 at the leading edge of each coolant flow portion 36 is convex
into the air stream 34. The aerodynamic surface of the shape 33
reduces the pressure drop at the entrance to the air flow portions
36, because air from the air stream 34 clings to the aerodynamic
surfaces of the shapes 33, rather than separating at the entrance
to the air flow portions 32. In addition, the aerodynamic shape 35
at the trailing edge of each coolant flow portion 36 creates a
partial vacuum on the downstream, so that an increased differential
pressure between the entrance and exit of each air flow portion 32
causes more air to be drawn into the heat exchange structure
30.
[0023] FIGS. 4A and 4B show profiles of coolant flow portions of a
heat exchange structure according to another embodiment of the
present invention. The shapes of the coolant flow portions 46 shown
in FIGS. 4A and 4B are based on the shapes of select wings (or
airfoils) developed by the National Advisory Committee for
Aeronautics (NACA). The coolant flow portion 46 shown in FIG. 4A is
based on the shape of an NACA 0009 airfoil, and the coolant flow
portion 46 shown in FIG. 4B is based on the shape of an NACA 0006
airfoil.
[0024] Each of the coolant flow portions 46 has a rounded shape 43
at a leading edge followed by a sharp, tapered shape 45 at a
trailing edge. The rounded shape 43 at the leading edge of each
coolant flow portion 46 is convex into the air stream 44. As such,
flow separation in the air stream 44 can be reduced, because the
air clings to the aerodynamic surfaces of the rounded shapes 43,
rather than separating. In addition, the tapered shape 45 at the
trailing edge of each coolant flow portion 46 draws the air flowing
into the air passage past the surface of the coolant flow portion
46, toward the exit of the air passage. Accordingly, the
aerodynamic shapes 43 and 45 of the coolant flow portions 46 may
facilitate the transition of air through the heat exchange
structure. While in FIGS. 4A and 4B the upper and lower portions of
the coolant flow portions 46 are asymmetrical about the x-axis, the
present invention is not limited thereto, and in other embodiments
the upper and lower portions of the coolant flow portions may be
symmetrical. In addition, the coolant flow portions may be designed
to have any suitable thickness, and the thickness is not limited to
the sizes shown in FIGS. 4A and 4B.
[0025] A heat exchange structure according to embodiments of the
present invention may be used in various types of heat exchangers,
such as heat exchangers configured to operate in a duct or a
plenum. In addition, a heat exchange structure according to
embodiments of the present invention may be used in a heat exchange
apparatus configured to operate in a free air stream, as described
in U.S. Patent Application No. ______, filed concurrently with this
application, which is incorporated herein by reference.
[0026] According to another embodiment of the present invention, a
method of manufacturing a heat exchange structure configured to
operate in an air stream includes providing coolant flow portions,
each of the coolant flow portions having at least one substantially
closed surface, arranging the coolant flow portions such that the
substantially closed surface is directed into the air stream,
providing air flow portions between adjacent coolant flow portions,
the air flow portions having air passages for receiving air from
the air stream, arranging the air flow portions such that the air
passages are directed into the air stream, and configuring the
substantially closed surface of the coolant flow portions to have
an aerodynamic shape.
[0027] In one embodiment, the step of configuring the substantially
closed surface of the coolant flow portions to have an aerodynamic
shape further includes designing the aerodynamic shape to be convex
into the air stream. The method may further include the step of
designing each of the coolant flow portions to have a trailing edge
at an end opposite the substantially closed surface, wherein the
trailing edge has a shape that is tapered rearwardly away from the
substantially closed surface.
[0028] As this invention has been described herein by way of
exemplary embodiments, many modifications and variations will be
apparent to those skilled in the art. Accordingly, it is to be
understood that the invention described herein may be embodied
other than as specifically described herein. For example, the
leading and trailing edges of the coolant flow portions may have
any aerodynamic shape, and are not limited to tapered, rounded, and
elliptical shapes. Further, it is to be understood that the steps
of the methods described herein are not necessarily in any
particular order.
* * * * *