U.S. patent application number 14/497753 was filed with the patent office on 2015-01-29 for craft outer skin heat exchanger and method for manufacturing a craft outer skin heat exchanger.
The applicant listed for this patent is Airbus Operations GmbH, Mahle Behr Industry GmbH & Co. KG. Invention is credited to Uwe Auer, Florian Eilken, Martin Moegel.
Application Number | 20150027676 14/497753 |
Document ID | / |
Family ID | 49300026 |
Filed Date | 2015-01-29 |
United States Patent
Application |
20150027676 |
Kind Code |
A1 |
Eilken; Florian ; et
al. |
January 29, 2015 |
Craft outer skin heat exchanger and method for manufacturing a
craft outer skin heat exchanger
Abstract
A heat exchanger comprising a plurality of heat transfer modules
disposed side by side so as to define a multilayer body of the heat
exchanger. Each heat transfer module has at least one heat transfer
medium channel configured to allow a flow of a heat-carrying medium
therethrough. At least one portion of the multilayer body of the
heat exchanger has a curvature configured to allow the heat
exchanger to be used as a curved outer skin section of a craft.
Adjacent heat transfer modules of the at least one portion of the
multilayer body are arranged with a tilt angle of their central
axes towards each other such that each heat transfer module is
aligned towards the center of a local osculating circle defined by
an outer surface of the heat exchanger.
Inventors: |
Eilken; Florian; (Hamburg,
DE) ; Auer; Uwe; (Hamburg, DE) ; Moegel;
Martin; (Ohmden, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Airbus Operations GmbH
Mahle Behr Industry GmbH & Co. KG |
Hamburg
Stuttgart |
|
DE
DE |
|
|
Family ID: |
49300026 |
Appl. No.: |
14/497753 |
Filed: |
September 26, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2013/056702 |
Mar 28, 2013 |
|
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|
14497753 |
|
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61620474 |
Apr 5, 2012 |
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Current U.S.
Class: |
165/168 ;
29/890.03 |
Current CPC
Class: |
B64D 33/10 20130101;
F28F 2280/00 20130101; F28F 21/00 20130101; B64D 13/00 20130101;
F28F 7/02 20130101; B64C 1/12 20130101; Y10T 29/4935 20150115 |
Class at
Publication: |
165/168 ;
29/890.03 |
International
Class: |
F28F 21/00 20060101
F28F021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2012 |
EP |
12002472.4 |
Claims
1. A heat exchanger comprising: a plurality of heat transfer
modules arranged side by side defining a multilayer body of the
heat exchanger, each heat transfer module being provided with at
least one heat transfer medium channel configured to allow a flow
of a heat-carrying medium therethrough, at least one portion of the
multilayer body of the heat exchanger being provided with a
curvature which is configured to allow the heat exchanger to be
used as a curved outer skin section of a craft, and adjacent heat
transfer modules of said at least one portion of the multilayer
body being arranged with a tilt angle of their central axes towards
each other such that each heat transfer module is aligned towards a
center of a local osculating circle defined by an outer surface of
the heat exchanger.
2. The heat exchanger according to claim 1, wherein the heat
exchanger multilayer body comprises at least one heat transfer
module having a heat transfer module body with a cross-sectional
shape tapering towards the center of the osculating circle.
3. The heat exchanger according to claim 2, wherein, in a heat
transfer module having a heat transfer module body with a
cross-sectional shape tapering towards the center of the osculating
circle, a tapering angle corresponds to the tilt angle of the
central axis of the heat transfer module towards the central axis
of an adjacent heat transfer module.
4. The heat exchanger according to claim 1, wherein the at least
one heat transfer medium channel provided in the heat transfer
modules is configured to allow a flow of a heat-carrying medium
therethrough in a direction parallel to a curvature axis of the
heat exchanger.
5. The heat exchanger according to claim 1, wherein the heat
transfer module body of at least one heat transfer module has an
inner surface adapted to form a section of an inner surface of the
heat exchanger and has a curvature adjusted to the curvature of an
inner surface of the craft outer skin section the heat exchanger is
intended to form.
6. The heat exchanger according to claim 1, wherein the heat
transfer module body of at least one heat transfer module has an
outer surface adapted to form a section of an outer surface of the
heat exchanger and has a curvature adjusted to the curvature of an
outer surface of the craft outer skin section the heat exchanger is
intended to form, wherein a curvature radius of the inner surface
of the heat transfer module body is smaller than a curvature radius
of the outer surface of the heat transfer module body.
7. The heat exchanger according to claim 1, wherein at least one
heat transfer module comprises a rib forming a protruding section
of an outer surface of the heat exchanger multilayer body.
8. The heat exchanger according to claim 7, wherein the rib is
formed integral with the heat transfer module body of the heat
transfer module.
9. The heat exchanger according to claim 7, wherein the rib has a
substantially conical cross-section.
10. The heat exchanger according to claim 7, wherein the rib is
provided with a rounded tip.
11. The heat exchanger according to claim 1, wherein at least two
adjacent heat transfer modules in the multilayer body of the heat
exchanger are separated from each other by a separating
element.
12. The heat exchanger according to claim 11, wherein the heat
exchanger comprises a separating element which is generally
U-shaped and has two substantially parallel legs extending between
side surfaces of the heat transfer module bodies of adjacent heat
transfer modules and a connecting bar extending between the legs in
a direction parallel to a curvature axis of the heat exchanger.
13. The heat exchanger according to claim 11, wherein the heat
exchanger comprises a separating element including airside fins
extending between side surfaces of the heat transfer module bodies
of adjacent heat transfer modules.
14. A method for manufacturing a heat exchanger, comprising the
steps: arranging a plurality of heat transfer modules side by side
so as to define a multilayer body of the heat exchanger, providing
each heat transfer module with at least one heat transfer medium
channel designed to allow a flow of a heat-carrying medium
therethrough, providing at least one portion of the multilayer body
of the heat exchanger with a curvature configured so as to allow
the heat exchanger to be used as a curved outer skin section of a
craft, and wherein adjacent heat transfer modules of said at least
one portion of the multilayer body are arranged with a tilt angle
of their central axes towards each other such that each heat
transfer module is aligned towards the center of a local osculating
circle defined by an outer surface of the heat exchanger.
15. The method according to claim 14, including the step of
arranging the heat transfer modules side by side in a manufacturing
form and fixing the heat transfer modules relative to one another,
while they are being arranged in the manufacturing form.
16. The method according to claim 15, including the step of
applying a biasing force to the heat transfer modules arranged side
by side the in a direction substantially perpendicular to side
surfaces of the heat transfer module bodies of the heat transfer
modules until the heat transfer modules are fixed relative to one
another.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application PCT/EP2013/056702 filed Mar. 28, 2013, designating the
United States and published on Oct. 10, 2013 as WO 2013/149936.
This application also claims the benefit of the U.S. Provisional
Application No. 61/620,474, filed on Apr. 5, 2012, and of the
European patent application No. 12002472.4, filed on Apr. 5, 2012,
the entire disclosures of which are incorporated herein by way of
reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a craft outer skin heat exchanger,
to the use of such an outer skin heat exchanger in an aircraft, and
to a method for manufacturing such a craft outer skin heat
exchanger.
[0003] Fuel cell systems enable low-emission, highly efficient
generation of electric current. For this reason, efforts are
currently made to use fuel cell systems to generate electrical
energy in various mobile applications, such as for example in
automotive engineering or aeronautics. It is, for example,
conceivable in an aircraft to replace the generators, which are
currently used to supply power on board and are driven by main
engines or the auxiliary power unit (APU), with a fuel cell system.
A fuel cell system, moreover, might also be used to supply the
aircraft with emergency power and replace the ram air turbine (RAT)
hitherto used as an emergency power system.
[0004] Besides electrical energy, a fuel cell during operation
generates thermal energy which has to be removed from the fuel cell
with the aid of a cooling system in order to prevent overheating of
the fuel cell. A fuel cell system installed in an aircraft, for
example for the on-board power supply, therefore has to be designed
in such a way that it is capable of meeting a high demand of
electrical energy. A fuel cell that has a high capacity for
generating electrical energy, however, also generates a large
amount of thermal energy and therefore has a high cooling
requirement. Moreover, on board of a craft, especially an aircraft,
a large number of further technical devices are provided, which
generate heat and have to be cooled in order to guarantee reliable
operation. For example in an aircraft, these technical devices
include, inter alia, the air conditioning unit and the electronic
control components of the aircraft.
[0005] In the aeronautic field, efforts are therefore being made to
employ outer skin heat exchangers in aircraft cooling systems in
order to remove heat from devices on board the aircraft which are
to be cooled into the surroundings of the aircraft. DE 10 2008 026
536 A1 and US 2011/0146957 A1, for example, describe a heat
exchanger which is directly integrated into the aircraft outer
skin. The heat exchanger comprises a cooling circuit allowing a
flow of a heat-carrying fluid therethrough, which is embedded in an
aircraft outer skin so as to be thermally coupled to the ambient
air.
[0006] It is further known from WO 2010/105744 A2 to provide a
cooler for an aircraft cooling system, which comprises a matrix
body designed to form a section of the aircraft outer skin. In the
matrix body of the cooler, there is provided a plurality of coolant
channels which extend from a first surface of the matrix body to a
second surface of the matrix body and allow a flow of coolant
through the matrix body.
SUMMARY OF THE INVENTION
[0007] An object on which the invention is based is to specify a
heat exchanger which is suitable for use as a craft outer skin heat
exchanger in any desired section of the craft outer skin, and a
method for manufacturing such a heat exchanger.
[0008] A heat exchanger according to the invention comprises a
plurality of heat transfer modules. The heat transfer modules are
arranged side by side so as to define a multilayer body of the heat
exchanger. Specifically, in the multilayer body of the heat
exchanger the heat transfer modules are arranged such that side
surfaces of heat transfer module bodies of adjacent heat transfer
modules face each other. The side surfaces of the heat transfer
module bodies preferably form the main surfaces of the heat
transfer module bodies, i.e., the surfaces of the heat transfer
module bodies having the largest area. The heat transfer module
bodies may further comprise an inner surface which is adapted to
form a section of an inner surface of the heat exchanger and an
outer surface which is adapted to form a section of an outer
surface of the heat exchanger.
[0009] For example, the heat transfer module bodies may be in the
form of a flat pipe having a very small thickness (the distance
between the side surfaces), a small height (the distance between
the inner surface and the outer surface), but a comparatively great
length (the distance between end faces of the heat transfer module
bodies). The heat transfer module bodies may be manufactured in an
extrusion process and may be of any desired material which allows
the use of the heat exchanger as a craft outer skin section.
Preferably, the material used to manufacture the heat transfer
module bodies has good heat transfer properties.
[0010] Each heat transfer module is provided with at least one heat
transfer medium channel designed to allow a flow of a heat-carrying
medium therethrough. The heat-carrying medium flowing through the
heat transfer medium channel may be any desired liquid or gaseous
fluid which is adapted to discharge heat from a heat generating
component. When the heat exchanger is installed in a craft, in
particular an aircraft, the heat exchanger may form a part of a
cooling system for cooling a heat generating component on board the
craft. The cooling system may comprise a conveying unit, such as a
pump, so as to convey the heat-carrying medium through the heat
transfer medium channels of the heat exchanger.
[0011] At least one portion of the multilayer body of the heat
exchanger is provided with a curvature which is designed so as to
allow the heat exchanger to be used as a curved outer skin section
of a craft. That to say, the multilayer body of the heat exchanger
is provided with a curvature to a curvature of a craft outer skin
section the heat exchanger is intended to form. The term
"curvature" in the context of the present application designates a
quantitative parameter which is inverse to a curvature radius and
which may be measured in 1/m.
[0012] Adjacent heat transfer modules of the at least one portion
of the multilayer body are arranged with a tilt angle of their
central axes towards each other such that each heat transfer module
is aligned towards the center of a local osculating circle defined
by an outer surface of the heat exchanger. A cross-sectional shape
of a heat transfer module body of the heat transfer modules and/or
a sequence of the heat transfer modules in the heat exchanger
multilayer body, may be selected so as to adjust the curvature of
the heat exchanger multilayer body as desired. The heat transfer
modules of the heat exchanger multilayer body may have identical or
different heat transfer module bodies.
[0013] The modular design of the heat exchanger allows a tailoring
of the shape, i.e., the curvature of the heat exchanger as desired
so as to enable the heat exchanger to be employed as a craft outer
skin heat exchanger in any desired section of the craft outer skin,
while using only a limited number of different heat transfer
modules. Hence, the heat exchanger may be installed as a craft
outer skin heat exchanger in any desired section of the craft outer
skin.
[0014] The heat exchanger multilayer body of the heat exchanger may
comprise heat transfer modules having a heat transfer module body
with a rectangular cross-section. To provide the heat exchanger
multilayer body of the heat exchanger with the desired curvature,
the heat exchanger multilayer body preferably further comprises at
least one heat transfer module having a heat transfer module body
with a cross-sectional shape tapering towards the center of the
osculating circle defined by the outer surface of the heat
exchanger. Heat transfer modules having a heat transfer module body
a cross-sectional shape of which tapers in a direction from an
outer surface to an inner surface of the heat transfer module body
may be employed in a heat exchanger with a convex curvature, while
heat transfer modules having a heat transfer module body with a
frustro-conical cross section which tapers in a direction from an
inner surface to an outer surface of the heat transfer module body
may be employed in a heat exchanger with a concave curvature.
[0015] The cross-sectional shape of the heat transfer module bodies
of the heat transfer modules in the heat exchanger multilayer body
may vary in a direction parallel to a curvature axis of the heat
exchanger. The variation of the cross-sectional shape should,
however, not result in significant change of the flow rate of the
heat-carrying medium along the heat transfer medium channels
provided in the heat transfer modules. The heat exchanger
multilayer body of the heat exchanger may be defined exclusively by
heat transfer modules having a heat transfer module body with a
cross-sectional shape tapering towards the center of the osculating
circle defined by the outer surface of the heat exchanger so as to
obtain a heat exchanger with a strong curvature, i.e., a small
curvature radius around a curvature axis. By employing heat
transfer modules having a heat transfer module body with a
rectangular cross-section and heat transfer modules having a heat
transfer module body with a cross-sectional shape tapering towards
the center of the osculating circle defined by the outer surface of
the heat exchanger in the heat transfer module body, a heat
exchanger with a slight curvature, i.e., a large curvature radius
around a curvature axis may be obtained.
[0016] In a heat transfer module having a heat transfer module body
with a cross-sectional shape tapering towards the center of the
osculating circle defined by the outer surface of the heat
exchanger a tapering angle may correspond to the tilt angle of the
central axis the heat transfer module towards the central axis of
an adjacent heat transfer module. As a result, side faces of
adjacent heat transfer modules are oriented parallel to each other.
Heat transfer modules having a heat transfer module body with a
cross-sectional shape tapering towards the center of the osculating
circle defined by the outer surface of the heat exchanger with a
large tapering angle can be used for manufacturing a heat exchanger
with a strong curvature, i.e., a small curvature radius around a
curvature axis. Contrary thereto, heat transfer modules having a
heat transfer module body with a cross-sectional shape tapering
towards the center of the osculating circle defined by the outer
surface of the heat exchanger with a small tapering angle can be
used for manufacturing a heat exchanger with a slight curvature,
i.e., a large curvature radius around a curvature axis.
[0017] The at least one heat transfer medium channel provided in
the heat transfer modules preferably is designed to allow a flow of
a heat-carrying medium therethrough in a direction parallel to a
curvature axis of the heat exchanger. When the heat exchanger is
installed in a craft so as to form a section of the craft outer
skin, ambient air flowing over the craft outer skin serves to
discharge heat from the heat-carrying medium flowing through the
heat transfer medium channel provided in the heat transfer modules.
When the heat exchanger is installed in an aircraft, the heat
transfer medium channels preferably extend in a direction parallel
to a longitudinal axis of the aircraft and hence parallel to the
direction of flow of the ambient air over the aircraft outer skin
in flight operation of the aircraft. A heat transfer medium may be
supplied to the heat transfer medium channels via a supply manifold
and discharged from the heat transfer medium channels via a
discharge manifold. The heat-carrying medium flow through the heat
transfer medium channels may be unidirectional or bidirectional. If
desired, the heat exchanger may be designed so as to allow at least
one diversion by 180.degree. of the heat-carrying medium flow
through the heat transfer medium channels so that the heat-carrying
medium flow meanders through the heat exchanger multilayer
body.
[0018] If desired, the heat transfer modules employed in the heat
exchanger may also comprise more than one heat transfer medium
channel. These heat transfer medium channels may be arranged on top
of each other in a direction along an axis of the heat transfer
modules, i.e., in a direction substantially parallel to the side
surfaces and substantially perpendicular to the inner and outer
surfaces of the heat transfer module bodies of the heat transfer
modules and extend parallel to a curvature axis of the heat
exchanger. A heat transfer medium channel adjacent to the outer
surface of a heat transfer module body of a heat transfer module
then advantageously serves to guide heat-carrying medium
transferring heat from a heat-generating device on board the craft,
which has a relatively high cooling power demand, while a heat
transfer medium channel adjacent to the inner surface of a heat
transfer module body of a heat transfer module advantageously is
assigned to heat-carrying medium transferring heat from
heat-generating devices on board the craft, which have a lower
cooling power demand.
[0019] The heat transfer module body of at least one heat transfer
module may have an inner surface which is adapted to form a section
of an inner surface of the heat exchanger and which has a curvature
which is adjusted to the curvature of an inner surface of the craft
outer skin section the heat exchanger is intended to form. If the
craft outer skin section and hence the heat exchanger has a convex
curvature, the inner surface of the heat transfer module body
preferably has a slight concave curvature. If the craft outer skin
section and hence the heat exchanger has a concave curvature, the
inner surface of the heat transfer module body preferably has a
slight convex curvature.
[0020] Similarly, the heat transfer module body of at least one
heat transfer module may have an outer surface which is adapted to
form a section of an outer surface of the heat exchanger and which
has a curvature which is adjusted to the curvature of an outer
surface of the craft outer skin section the heat exchanger is
intended to form. If the craft outer skin section and hence the
heat exchanger has a convex curvature, the outer surface of the
heat transfer module body preferably has a slight convex curvature.
If the craft outer skin section and hence the heat exchanger has a
concave curvature, the outer surface of the heat transfer module
body preferably has a slight concave curvature. Preferably, a
curvature radius of the inner surface of the heat transfer module
is smaller than the curvature radius of the outer surface of the
heat transfer module body.
[0021] At least one heat transfer module may comprise a rib which
forms a protruding section of an outer surface of the heat
exchanger multilayer body. Preferably, the rib extends in a
direction parallel to a curvature axis of the heat exchanger. When
the heat exchanger is installed in an aircraft, the rib preferably
extend in a direction parallel to a longitudinal axis of the
aircraft and hence parallel to the direction of flow of the ambient
air over the aircraft outer skin in flight operation of the
aircraft. The rib enhances the cooling performance of the heat
exchanger and protects the multilayer body and in particular its
outer surface from external influences. The rib, however, increases
the aerodynamic drag caused by the heat exchanger when installed in
a craft, in particular an aircraft.
[0022] The rib may be formed integral with the heat transfer module
body of the heat transfer module. Further, the rib may be composed
of the same material as the heat transfer module body of the heat
transfer module, but also of a different material. For example, the
rib may be produced from a metal or plastic material, preferably a
fiber-reinforced plastic material. The rib may be integrally formed
with the heat transfer module body of the heat transfer module in
an extrusion process. The rib may have a substantially triangular
cross-section. Further, the rib may have a rounded tip.
[0023] The heat exchanger may comprise heat transfer modules which
are disposed immediately adjacent to each other. In another
embodiment of the heat exchanger at least two adjacent heat
transfer modules in the multilayer body of the heat exchanger may
be separated from each other by a separating element. The
separating element preferably is composed of a material with good
thermal transfer characteristics. Alternatively, the separating
element may have isolating characteristics. In general, the
separating element may be used as a spacer between heat transfer
modules in the multilayer body of the heat exchanger. As a spacer,
the separating element may be designed and arranged so as to
prevent the entry of ambient air in the space between two adjacent
heat transfer modules. The heat exchanger then has the function of
a surface heat exchanger and causes only low aerodynamic losses
when employed in a craft, in particular an aircraft.
[0024] The heat exchanger may comprise a separating element which
is generally U-shaped and has two substantially parallel legs
extending between side surfaces of the heat transfer module bodies
of adjacent heat transfer modules. Further, the separating element
may comprise a connecting bar extending between the legs in a
direction parallel to a curvature axis of the heat exchanger. The
connecting bar prevents the entry of ambient air in the space
between two adjacent heat transfer modules and allows the formation
of a smooth outer surface of the heat exchanger. An outer surface
of the connecting bar may extend parallel to the outer surfaces of
the heat transfer module bodies of the adjacent heat transfer
modules separated from each other by the separating element and may
be flat or curved, as desired.
[0025] Alternatively or additionally thereto, the heat exchanger
may comprise a separating element including airside fins extending
between side surfaces of the heat transfer module bodies of
adjacent heat transfer modules. The airside fins may be offset fins
or louvered fins and may be designed in accordance with the heat
transfer requirements of the heat exchanger. When the heat
exchanger is installed in a craft, in particular an aircraft, a
separating element of this kind allows ambient air to enter the
space between two adjacent heat transfer modules and to thus
enhance the cooling capacity of the heat exchanger. So as to keep
the additional aerodynamic drag caused by the design of the
separating element as low as possible, the separating element may
comprise sharp-edged fine grooves which, when the heat exchanger is
installed in a craft, in particular an aircraft, are oriented
parallel to flow lines of the ambient air flowing over the outer
surface of craft, when the craft is moving. Such a surface
structure brings about a so-called "shark skin effect," i.e., it
brings about a reduction of the frictional drag caused by the heat
exchanger.
[0026] The heat exchanger is in particular suitable for use in an
aircraft. An aircraft cooling system thus may comprise at least one
heat exchanger as described above which may be integrated into the
aircraft outer skin, preferably in a lower region of aircraft
fuselage so as to protect the heat exchanger from solar
radiation.
[0027] In a method for manufacturing a heat exchanger a plurality
of heat transfer modules is arranged side by side so as to define a
multilayer body of the heat exchanger, wherein each heat transfer
module is provided with at least one heat transfer medium channel
designed to allow a flow of a heat-carrying medium therethrough,
wherein at least one portion of the multilayer body of the heat
exchanger is provided with a curvature which is designed so as to
allow the heat exchanger to be used as a curved outer skin section
of a craft, and wherein adjacent heat transfer modules of the at
least one portion of the multilayer body are arranged with a tilt
angle of their central axes towards each other such that each heat
transfer module is aligned towards the center of a local osculating
circle defined by an outer surface of the heat exchanger.
[0028] Preferably, the heat transfer modules are arranged side by
side in a manufacturing form and fixed relative to one another,
while being arranged in the manufacturing form.
[0029] A biasing force may be applied to the heat transfer modules
arranged side by side the in a direction substantially
perpendicular to side surfaces of the heat transfer module bodies
of the heat transfer modules until the heat transfer modules are
fixed relative to one another.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Preferred embodiments of the invention are now explained in
more detail with reference to the appended schematic drawings, of
which
[0031] FIGS. 1A to 1D show illustrations of four different
embodiments of a heat transfer module designed to form a layer of a
heat exchanger multilayer body,
[0032] FIG. 2 shows an illustration of a heat exchanger having a
multilayer body after manufacturing and before integration into a
craft outer skin,
[0033] FIG. 3 shows a cross-sectional view of a heat exchanger
having a multilayer body when integrated into a craft outer
skin,
[0034] FIG. 4 shows a cross-sectional view of an alternative heat
exchanger when integrated into a craft outer skin,
[0035] FIG. 5 shows a three-dimensional view of the alternative
heat exchanger according to FIG. 4, and
[0036] FIG. 6 shows an illustration of a heat exchanger when
accommodated in a manufacturing form during its manufacturing
process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] FIGS. 1A to 1D show four different embodiments of heat
transfer modules 10, 20, 30, 40, each of which may form a layer of
a multilayer body 102, 202, 302 of a heat exchanger 100, 200, 300
as, for example, shown in one of FIGS. 2 to 5. Each heat exchanger
multilayer body 102, 202, 302 comprises a plurality of heat
transfer modules 10, 20, 30, 40 as shown in FIGS. 1A to 1D. If
desired, only one type of heat transfer modules 10, 20, 30, 40
might be employed in the heat exchanger multilayer body 102, 202,
302. Alternatively, it is, however, also conceivable to equip the
heat exchanger multilayer body 102, 202, 302 with at least two
different types of heat transfer modules 10, 20, 30, 40 as shown in
FIG. 1A, 1B, 1C or 1D.
[0038] The heat transfer module 10 shown in FIG. 1A comprises a
heat transfer module body 10a and a rib or fin 12 which is formed
integrally with the heat transfer module body 10a. The rib or fin
12 and the heat transfer module body 10a, however, also may be
formed as separate components which are connected to one another so
as to form the heat transfer module 10 shown in FIG. 1A. The heat
transfer module body 10a of the heat transfer module 10 has a
generally rectangular cross-section and is provided with four heat
transfer medium channels 14. The heat transfer medium channels 14
also have a generally rectangular cross-section and are designed to
allow a flow of heat transfer medium therethrough. Specifically,
the heat transfer medium channels 14 are designed so as to allow
the heat transfer medium to flow through the heat transfer module
body 10a of the heat transfer module 10 in a direction
perpendicular to an axis A of the of the heat transfer module
10.
[0039] The heat transfer module body 10a of the heat transfer
module 10 further comprises two substantially parallel side
surfaces 16 as well as an inner surface 18. The inner surface 18 of
the heat transfer module body 10a is disposed opposite from the rib
or fin 12 and may either be flat, as shown in FIG. 1A, or may be
provided with a desired curvature. When the heat transfer module 10
is installed in a heat exchanger multilayer body 102, 202, 302, the
inner surface 18 of the heat transfer module body 10a forms a
section of an inner surface 104, 204, 304 of the heat exchanger
100, 200, 300. Contrary thereto, the rib or fin 12 forms a
protruding section of an outer surface 106, 206, 306 of the heat
exchanger 100, 200, 300. As becomes apparent from FIG. 1A, the rib
or fin 12 has a substantially triangular cross-section, i.e., a
cross-section which tapers in a direction parallel to the axis A of
the heat transfer module 10 from a base of the rib or fin 12 which
is disposed adjacent to the heat transfer module body 10a to a tip
of the rib or fin 12 which is disposed distal from the heat
transfer module body 10a. The tip of the rib or fin 12 has a
rounded shape.
[0040] The heat transfer module 20 of FIG. 1B differs from the heat
transfer module 10 shown in FIG. 1A in that it does not have a rib
or fin attached to or formed integrally with a heat transfer module
body 20a. Again, the heat transfer module body 20a of the heat
transfer module 20 has a generally rectangular cross-section and is
provided with four heat transfer medium channels 24, which also
have a generally rectangular cross-section. The heat transfer
module body 20a of the heat transfer module 20 comprises two
substantially parallel side surfaces 26 as well as an inner surface
28, wherein the inner surface 28 of the heat transfer module body
20a is adapted to form a section of an inner surface 104, 204, 304
of a heat exchanger 100, 200, 300, when the heat transfer module 20
is installed in the heat exchanger multilayer body 102, 202, 302.
The inner surface 28 may either be flat, as shown in FIG. 1B, or
may be provided with a curvature.
[0041] The heat transfer module body 20a of the heat transfer
module 20 further comprises an outer surface 22 which is disposed
opposite from the inner surface 28. When the heat transfer module
20 is installed in a heat exchanger 100, 200, 300, the outer
surface 22 of the heat transfer module body 20a forms a section of
an outer surface 106, 206, 306 of the heat exchanger 100, 200, 300.
Like the inner surface 28, the outer surface 22 may either be flat,
as shown in FIG. 1B, and extend substantially parallel to the inner
surface 28, or may be provided with a curvature.
[0042] The heat transfer module 30 of FIG. 1C generally corresponds
to the heat transfer module 20 shown in FIG. 1B, its heat transfer
module body 30a, however, has a cross-sectional shape tapering
towards the center of an osculating circle defined by an outer
surface 106, 206, 306 of a heat exchanger 100, 200, 300 including
the heat transfer module 30. Correspondingly, each of the heat
transfer medium channels 34 also has a cross-sectional shape
tapering towards the center of the osculating circle defined by the
outer surface 106, 206, 306 of the heat exchanger 100, 200, 300
including the heat transfer module 30. Two side surfaces 36 of the
heat transfer module body 30a are inclined so as to approach each
other in a direction parallel to the axis A of the heat transfer
module 30 from the outer surface 32 to the inner surface 38 of the
heat transfer module body 30a. The side surfaces 36 may be inclined
so as to define a tapering angle of the cross-sectional shape of
the heat transfer module body 30a of approximately 1 to 2.degree.,
in particular 1.6.degree..
[0043] The inner surface 38 of the heat transfer module body 30a is
adapted to form a section of the inner surface 104, 204, 304 of a
heat exchanger 100, 200, 300, when the heat transfer module 30 is
installed in the heat exchanger multilayer body 102, 202, 302 of
the heat exchanger 100, 200, 300. The inner surface 38 has a
concave shape. The outer surface 32 of the heat transfer module
body 30a is disposed opposed from the inner surface 38 and is
adapted to form a section of an outer surface 106, 206, 306 of the
heat exchanger 100, 200, 300, when the heat transfer module 30 is
installed in the heat exchanger multilayer body 102, 202, 302 of
the heat exchanger 100, 200, 300. The outer surface 32 has a convex
shape. It is, however, also conceivable to provide the heat
transfer module body 30a of the heat transfer module 30 with flat
inner and outer surfaces 38, 32, or with a convex inner surface 38
and a concave outer surface 32.
[0044] The heat transfer module 40 as shown in FIG. 1D generally
corresponds to the heat transfer module 10 as shown in FIG. 1A, its
heat transfer module body 40a, however, has a cross-sectional shape
tapering towards the center of an osculating circle defined by an
outer surface 106, 206, 306 of a heat exchanger 100, 200, 300
including the heat transfer module 40. Correspondingly, each of the
heat transfer medium channels 44 also has a cross-sectional shape
tapering towards the center of the osculating circle defined by the
outer surface 106, 206, 306 of the heat exchanger 100, 200, 300
including the heat transfer module 40. Two side surfaces 46 of the
heat transfer module body 40a are inclined so as to approach each
other in a direction parallel to the axis A of the heat transfer
module 40 from the outer surface 42 to the inner surface 48 of the
heat transfer module body 40a. The side surfaces 46 may be inclined
so as to define a tapering angle of the cross-sectional shape of
the heat transfer module body 40a of approximately 1 to 2.degree.,
in particular 1.6.degree.. The inner surface 48 of the heat
transfer module body 40a has a concave shape. It is, however, also
conceivable to provide the heat transfer module body 40a of the
heat transfer module 40 with a flat or a convex inner surface
38.
[0045] The heat exchanger 100 shown in FIG. 2 comprises a
multilayer body 102 formed of two different types of heat transfer
modules 40, 30, namely eleven heat transfer modules 40 as shown in
FIG. 1D and ten heat transfer modules 30 as shown in FIG. 1C. In
the multilayer body 102 of the heat exchanger 100 according to FIG.
2, the different heat transfer modules 40, 30 are arranged such
that the side surfaces 46 of a heat transfer module 40 face the
side surfaces 36 of two adjacent heat transfer module 30 and vice
versa. The heat transfer modules 40, 30 thus define alternating
layers of the multilayer body 102. Specifically, adjacent heat
transfer modules 40, 30 of the multilayer body 102 are arranged
with a tilt angle of their central axes A towards each other such
that each heat transfer module 30, 40 is aligned towards the center
of a local osculating circle defined by the outer surface 106 of
the heat exchanger 100. Thus, a multilayer body 102 of the heat
exchanger 100 is defined which is curved around a curvature axis
C.
[0046] The curvature radius of the multilayer body 102 depends on
the shape of the heat transfer module bodies 40a, 30a. For example,
a minimum curvature radius of the multilayer body 102 of 500 mm can
be obtained by employing in the multilayer body 102 heat transfer
modules 40, 30 having heat transfer module bodies 40a, 30a, the
side surfaces 46, 36 of which define a tapering angle of the cross
sectional shape of the heat transfer module body 40a of
approximately 1.6.degree.. The heat transfer medium channels 44, 34
of the heat transfer modules 40, 30 allow a flow of heat transfer
medium through the heat transfer module bodies 10a, 30a of the heat
transfer modules 10, 30 in a direction parallel to the curvature
axis C of the of the heat exchanger 100.
[0047] The curvature radius of the heat exchanger 100 thus can be
tailored by suitably adapting the cross-sectional shape of the heat
transfer module bodies 40a, 30a of the heat transfer modules 40,
30. It is, however, also conceivable to tailor the curvature radius
of the heat exchanger 100 by installing different types of heat
transfer modules, i.e., heat transfer modules, the heat transfer
module bodies of which have different cross-sectional shapes in the
multilayer body 102 of the heat exchanger 100. For example, in the
heat exchanger 100 of FIG. 2, instead of heat transfer modules 40,
heat transfer modules 10, the heat transfer module bodies 10a of
which have a rectangular cross-sectional shape, can be employed so
as to increase the curvature radius of the heat exchanger 100. Of
course, all or only a selected number of heat transfer modules 40
may be replaced by heat transfer modules 10. Similarly, all or a
selected number of heat transfer modules 30 of the heat exchanger
100 may be replaced by heat transfer modules 20 so as to increase
the curvature radius of the heat exchanger 100.
[0048] In the embodiment of a heat exchanger 100 shown in FIG. 2,
the multilayer body 102 further comprises a plurality of separating
elements 50. A cross-sectional view of a separating element 50 in
the direction of the curvature axis C is shown in the detail view
incorporated in FIG. 2. The separating elements 50 are provided in
between the alternating heat transfer modules 40, 30 and thus serve
as spacers for spacing adjacent heat transfer modules 40, 30 apart
from each other. Each of the separating elements 50 is generally
U-shaped and comprises two substantially parallel legs 52 which
extend between the side surfaces 46, 36 of the heat transfer module
bodies 40a, 30a of adjacent heat transfer modules 40, 30. Similar
to the heat transfer module bodies 40a, 30a of the heat transfer
modules 40, 30, the legs 52 of the separating elements 50 may have
a cross-sectional shape tapering towards the center of an
osculating circle defined by the outer surface 106 of the heat
exchanger 100. By employing separating elements 50 having legs 52
with a cross-sectional shape tapering towards the center of an
osculating circle defined by the outer surface 106 of the heat
exchanger 100 smaller curvature radii of the heat exchanger 100 can
be achieved, than by employing separating elements 50 having legs
52 with a rectangular cross-section. It is, however, also
conceivable to provide all or a selected number of separating
elements 50 with legs 52 having a rectangular cross-section so as
to tailor the curvature radius of the heat exchanger 100 as
desired.
[0049] A connecting bar 53 extends between the legs 52 of each
separating element 50 in a direction parallel to the curvature axis
C of the heat exchanger 100 and has an outer surface which is
designed to form a smooth section of an outer surface of the
multilayer body 102. Specifically, the outer surface of the
multilayer body 102 is formed by a periodical sequence of the outer
surface of a connecting bar of a separating element 50, a rib or
fin 12 of a heat transfer module 40, a connecting bar of a further
separating element 50, and the outer surface 32 of a heat transfer
modules 30. The connecting bars 53 of the separating elements 50
prevents the entry of ambient air in the space between two adjacent
heat transfer modules 30, 40. Hence, the heat exchanger 100 has the
function of a surface heat exchanger and causes only low
aerodynamic losses when employed in a craft, in particular an
aircraft.
[0050] As described above, the outer surface 32 of the heat
transfer modules 30 has a convex shape which is adjusted to the
desired curvature radius of the outer surface 106 of the heat
exchanger 100 around the curvature axis C. Like the outer surface
32 of the heat transfer modules 30, also the outer surface of the
connecting bars 53 of the separating elements 50 may be provided
with a convex curvature which is adjusted to the desired curvature
radius of the outer surface 106 of the heat exchanger 100 around
the curvature axis C. Further, like the inner surfaces 38, 48 of
the heat transfer modules 30, 40, inner surfaces of the legs 52 of
the separating elements 50 may be provided with a concave curvature
which is adjusted to the desired curvature radius of the inner
surface 104 of the heat exchanger 100 around the curvature axis
C.
[0051] As an alternative to the separating elements 50 shown in
FIG. 2, the multilayer body 102 of the heat exchanger 100 may also
be provided with separating elements 250' which are employed in the
heat exchanger 300 of FIGS. 4 and 5 and which will be described in
more detail below.
[0052] The heat exchanger 100 as shown in FIG. 2 further comprises
two connecting elements 60. Each of the connecting elements 60 has
a substantially L-shaped cross section and comprises a first leg 62
and a second leg 64. The first leg 62 of each connecting element 60
forms an outermost layer of the multilayer body 102. The second leg
64 extends substantially perpendicular from the first leg 62. The
connecting elements 60 are adapted to be connected to an outer skin
of a craft in an aerodynamically favorable manner in such a way
that the heat exchanger 100 is integrated into the craft outer skin
so as to form a section thereof.
[0053] FIG. 3 shows a further heat exchanger 200 having a
multilayer body 202, when integrated into a craft outer skin 210 so
as to form a section thereof. Connecting elements 260 are provided
which serve to integrate the heat exchanger 200 into the craft
outer skin 210 in an aerodynamically favorable manner. The
multilayer body 202 of the heat exchanger 200 comprises six heat
transfer modules 40 as shown in FIG. 1D, one heat transfer module
10 as shown in FIG. 1A, four heat transfer modules 20 as shown in
FIG. 1B and three heat transfer modules 30 as shown in FIG. 1C. In
the layer sequence of the multilayer body 202, a heat transfer
module 20 or 30 as shown in FIG. 1B or FIG. 1C alternates with a
heat transfer module 40 as shown in FIG. 1D and once with a heat
transfer module 10 as shown in FIG. 1A. As already discussed above,
by appropriately selecting the type and the sequence of heat
transfer modules in the multilayer body 202 of the heat exchanger
200, the curvature of the heat exchanger 200 can be tailored as
desired so as to adapt it to the shape and in particular the
curvature of the craft outer skin into which the heat exchanger 200
is to be integrated. Specifically, the curvature of the heat
exchanger 200 matches the curvature of the craft outer skin so as
to reduce aerodynamic losses caused by the heat exchanger as low as
possible.
[0054] The heat exchanger 200 of FIG. 3 also is provided with
separating elements 50 in between the alternating heat transfer
modules 10, 20, 30, 40 and also in between the two outermost heat
transfer modules 20, 40 and the connecting elements 260. The
connecting bars 53 of the separating elements 50 each are provided
with an outer surface which is designed to form a smooth section of
an outer surface of the multilayer body 202.
[0055] The alternative heat exchanger 300 of FIGS. 4 and 5, which
forms a section of a craft outer skin 310, differs from the heat
exchanger 200 shown in FIG. 3 only in that it comprises, instead of
separating elements 50, separating elements 250' including airside
fins. The separating elements 250' allow cooling medium, in
particular ambient air, to enter the spaces between adjacent heat
transfer modules 10, 20, 30, 40 and to thus support the heat
transfer from a heat transfer medium flowing through the heat
transfer channels 14, 24, 34, 44 of heat transfer modules 10, 20,
30, 40 to the cooling medium.
[0056] The heat exchangers 100, 200, 300 described above are in
particular suitable for integration into an aircraft outer skin and
may be used in an aircraft to supply cooling energy to heat
generating components on board the aircraft. The heat exchangers
100, 200, 300 shown in FIGS. 2 to 4 have a convex curvature an thus
are adapted to form a section of an aircraft outer skin having a
convex curvature, for example in the region of a tail of the
aircraft. The heat exchangers, however, might also be provided with
a concave curvature so as to be suitable to form a section of an
aircraft outer skin having a concave curvature. If desired, the
heat transfer module bodies of the heat transfer modules may have a
convex inner surface and a concave outer surface. Further, be
appropriately selecting the shape of the heat transfer module
bodies of the heat transfer modules and/or the sequence of the heat
transfer modules, heat exchangers having a varying curvature may be
obtained. For example, a heat exchanger may be obtained having a
first section with a convex curvature and a second section having a
concave curvature.
[0057] When the heat exchanger 100, 200, 300 is installed in an
aircraft, heat transfer medium flowing through the heat transfer
channels 14, 24, 34, 44 provided in the heat transfer module bodies
10a, 20a, 30a, 40a of the heat transfer modules 10, 20, 30, 40 is
cooled by heat transfer to the ambient air flowing over the outer
surface of the heat exchanger multilayer body 102, 202, 302, in
particular during flight operation of the aircraft. Typically, the
heat exchanger 100, 200, 300 is installed in the aircraft such that
the ribs or fins 12 extend in a direction parallel to a direction
of the flow of ambient air over the aircraft outer skin during
flight operation of the aircraft. The ribs or fins 12 enhance the
cooling performance of the heat exchanger 100, 200, 300, but
increase the aerodynamic drag caused by the heat exchanger 100,
200, 300.
[0058] The cooling performance of the heat exchanger 100, 200, 300
can further be enhanced by providing the heat exchanger 100, 200,
300 with separating elements 250' which allow ambient air flowing
over the aircraft outer skin during flight operation of the
aircraft to enter the spaces provided in the heat exchanger
multilayer body 102, 202, 302 between adjacent heat transfer
modules 10, 20, 30, 40 and to thus directly discharge heat from the
heat transfer medium flowing through the heat transfer channels 14,
24, 34, 44 of heat transfer modules 10, 20, 30, 40. Separating
elements 250' allowing ambient air to enter the spaces provided in
the heat exchanger multilayer body 102, 202, 302 between adjacent
heat transfer modules 10, 20, 30, 40, however, also increase the
aerodynamic losses caused by the heat exchanger 100, 200, 300.
[0059] FIG. 6 shows a manufacturing form 400 used for manufacturing
a heat exchanger 100, 200, 300. A plurality of layers comprising
heat transfer modules 10, 20, 30 and/or 40 and separating elements
50, 250 and/or 250' are accommodated in the manufacturing form 400.
The type and the sequence of heat transfer modules 10, 20, 30
and/or 40 in the manufacturing form 400 are selected such that a
curvature of the heat exchanger 100, 200 or 300 is obtained which
matches the curvature of the section of the craft outer skin the
heat exchanger 100, 200, 300 is intended to form. When received in
the manufacturing form 400, the plurality of layers is fixed
relative to one another.
[0060] As shown in FIG. 6, the manufacturing form 400 is provided
with a support 410 for supporting the layers of heat transfer
modules 10, 20, 30, 40 in line with the curvature of the section of
the outer skin of the craft, the heat exchanger 100, 200 or 300 is
intended to form. Further, the manufacturing form 400 comprises a
movable element 420 which is pre-stressed by use of two spiral
springs 430 and which serves to apply a biasing force to the heat
transfer modules 10, 20, 30, 40 in a direction substantially
perpendicular to the side surfaces 16, 26, 36, 46 of the heat
transfer module bodies 10a, 20a, 30a, 40a of the heat transfer
modules 10, 20, 30, 40 until the heat transfer modules 10, 20, 30,
40 are fixed relative to one another.
[0061] As is apparent from the foregoing specification, the
invention is susceptible of being embodied with various alterations
and modifications which may differ particularly from those that
have been described in the preceding specification and description.
It should be understood that I wish to embody within the scope of
the patent warranted hereon all such modifications as reasonably
and properly come within the scope of my contribution to the
art.
* * * * *