U.S. patent application number 14/464152 was filed with the patent office on 2016-08-11 for mixed material tubular heat exchanger.
This patent application is currently assigned to HONEYWELL INTERNATIONAL INC.. The applicant listed for this patent is HONEYWELL INTERNATIONAL INC.. Invention is credited to Matthew Pohlman.
Application Number | 20160231072 14/464152 |
Document ID | / |
Family ID | 56566708 |
Filed Date | 2016-08-11 |
United States Patent
Application |
20160231072 |
Kind Code |
A1 |
Pohlman; Matthew |
August 11, 2016 |
MIXED MATERIAL TUBULAR HEAT EXCHANGER
Abstract
Apparatus for cooling bleed air on an aircraft may include a
source of cooling fluid driven by an engine of the aircraft, a
source of bleed air driven by the engine and a heat exchanger
configured allow the cooling fluid to pass over tubes through which
the bleed air flows. The heat exchanger may have a high-temperature
zone constructed from material with a first density, and a
low-temperature zone constructed from material with a second
density lower than the first density.
Inventors: |
Pohlman; Matthew;
(Huntington Beach, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONEYWELL INTERNATIONAL INC. |
Morristown |
NJ |
US |
|
|
Assignee: |
HONEYWELL INTERNATIONAL
INC.
MORRISTOWN
NJ
|
Family ID: |
56566708 |
Appl. No.: |
14/464152 |
Filed: |
August 20, 2014 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F 2275/04 20130101;
F28F 21/087 20130101; F28F 13/14 20130101; F02M 26/29 20160201;
Y02T 50/60 20130101; Y02T 50/671 20130101; F02C 7/185 20130101;
F28D 7/16 20130101; F28D 1/05333 20130101; F28D 2021/0026 20130101;
F28D 21/0003 20130101; F28F 1/006 20130101; F28F 21/081 20130101;
F02C 6/08 20130101; Y02T 50/676 20130101; F05D 2300/522 20130101;
F05D 2260/213 20130101; F28F 21/083 20130101; F28D 2021/0021
20130101; F28F 21/084 20130101; F28F 21/086 20130101 |
International
Class: |
F28F 21/08 20060101
F28F021/08; F28D 1/053 20060101 F28D001/053; F28F 1/00 20060101
F28F001/00; F28F 13/14 20060101 F28F013/14 |
Goverment Interests
GOVERNMENT RIGHTS
[0001] This invention was made with Government support under
Contract FA8650-09-d-2922, program GE AETD Ti HX Demo awarded by
U.S. Air Force. The Government has certain rights in this
invention.
Claims
1. Apparatus for cooling bleed air on an aircraft comprising: a
source of cooling fluid driven by an engine of the aircraft; a
source of bleed air driven by the engine; a heat exchanger
configured to allow the cooling fluid to pass over tubes through
which the bleed air flows; the heat exchanger having, a) a
high-temperature zone constructed from material with a first
density, and b) a low-temperature zone constructed from material
with a second density lower than the first density.
2. The apparatus of claim 1; wherein the heat exchanger has a
medium-temperature zone interposed between the high-temperature
zone and the low-temperature zone; and wherein the
medium-temperature zone is constructed from material with a third
density lower than the first density and higher than the second
density.
3. The apparatus of claim 2 wherein the medium-temperature zone
includes tube segments constructed from titanium or titanium
alloy.
4. The apparatus of claim 1 wherein the high-temperature zone
includes tube segments constructed from stainless steel, nickel or
nickel-based alloy.
5. The apparatus of claim 1 wherein the low-temperature zone
includes tube-segments constructed from aluminum or aluminum-based
alloy.
6. The apparatus of claim 1 wherein the source of cooling fluid is
a by-pass fan of the engine.
7. The apparatus of claim 1: wherein the heat exchanger includes a
hot-fluid inlet manifold constructed from the material with the
first density; and wherein the heat exchanger includes a hot-fluid
outlet manifold constructed from the material with the second
density.
8. A heat exchanger comprising: a high-temperature zone constructed
from material with a first density, and a low-temperature zone
constructed from material with a second density lower than the
first density.
9. The heat exchanger of claim 8 further comprising a
medium-temperature zone interposed between the high-temperature
zone and the low-temperature zone, wherein the medium-temperature
zone is constructed from material with a third density lower than
the first density and higher than the second density.
10. The heat exchanger of claim 9 wherein the medium-temperature
zone includes tube segments constructed from titanium or
titanium-based alloy.
11. The heat exchanger of claim 9 comprising: a plurality of
hot-fluid passage tubes, each of the tubes including, a) a
high-temperature tube segment constructed from the material with
the first density, b) a low-temperature tube segment constructed
from the material with the second density and c) a
medium-temperature tube segment constructed from material with a
third density, said third being lower than the first density and
higher than the second density.
12. The heat exchanger of claim 8 wherein the high-temperature zone
includes tube segments constructed from stainless steel, nickel or
nickel-based alloy.
13. The heat exchanger of claim 8 wherein the high-temperature zone
includes tube segments constructed from titanium or titanium-based
alloy.
14. The heat exchanger of claim 8 wherein the low-temperature zone
includes tube-segments constructed from aluminum, aluminum-based
alloy, titanium or titanium alloy.
15. The heat exchanger of claim 8 further comprising: a hot-fluid
inlet manifold constructed from the material with the first
density; and a hot-fluid outlet manifold constructed from the
material with the second density.
16. The heat exchanger of claim 15: wherein the medium-temperature
tube segments are brazed to the high-temperature tube segment with
a first brazing filler that remains solid at a temperature of at
least 1000.degree. F.; and wherein the medium-temperature tube
segments are brazed to the low-temperature tube segments with a
second brazing filler that remains solid at a temperature of at
least 600.degree. F.
17. The heat exchanger of claim 15 wherein the high-temperature
tube segments are brazed to a hot-fluid inlet manifold with brazing
filler that remains solid at a temperature of at least 1200.degree.
F.
18. A method for cooling hot fluid comprising the steps: passing
the hot fluid through first tube segments of a heat exchanger;
passing the hot fluid through second tube segments of the heat
exchanger directly from the first tube segments, the second tube
segments having a lower temperature tolerance than the first tube
segments; passing cooling fluid over the first segments to cool the
hot fluid to a temperature within a range of temperature tolerance
of the second tube segments; and passing the cooling fluid over the
second segments to further cool the hot fluid.
19. The method of claim 18 further comprising the steps: passing
the hot fluid through third tube segments of the heat exchanger,
the third tube segments having a lower temperature tolerance than
the second tube segments; passing the cooling fluid over the second
segments to cool the hot fluid to a temperature within a range of
temperature tolerance of the third tube segments; and passing the
cooling fluid over the third segments to further cool the hot
fluid.
20. The method of claim 18: wherein the hot fluid is bleed air
driven with an engine of the aircraft; and wherein the cooling
fluid is by-pass air driven by the engine.
Description
BACKGROUND OF THE INVENTION
[0002] The present invention relates to heat exchangers and, more
particularly, to heat exchangers that may be employed in an
aircraft to cool bleed air from an engine or on ground vehicles to
cool exhaust gas or to heat compressed air.
[0003] In a typical turbine-engine powered aircraft, bleed air may
be extracted from one or more engines and employed to operate
various ancillary systems of the aircraft. For example, bleed air
may be employed to drive an environmental control system (ECS),
wing ice protection systems, fuel tank inerting and the like. In
order to effectively use bleed air in such systems the bleed air
must first be cooled after being extracted from an engine
compressor.
[0004] Bleed air is usually discharged from an engine compressor at
a temperature of 1200.degree. F. or higher. The bleed air may be
cooled, in one or more heat exchangers, to a temperature of about
300.degree. F. or lower before being introduced into an ancillary
system of the aircraft. Heat exchangers that are capable of
withstanding inlet temperatures of 1200.degree. F. are typically
constructed from dense materials such as stainless steel or nickel
based alloy.
[0005] Bleed air cooling may be performed by passing the bleed air
through one or more heat exchangers which may employ ambient air as
a cooling medium. In some instances, the ambient cooling air may be
by-pass air propelled with a by-pass fan of the engine or ram air
or air from an external fan. In this context, a heat exchanger
capable of reducing temperature from 1200.degree. F. to 300.degree.
F. must be large enough to allow for sufficient residence time of
the bleed air to achieve the requisite reduction of temperature.
Such a heat exchanger may be quite heavy when constructed from
dense stainless steel or nickel based alloy.
[0006] As can be seen, there is a need for a system for reducing
bleed air temperature without incurring a weight penalty associated
with a heat exchanger constructed entirely from dense
high-temperature tolerant materials.
SUMMARY OF THE INVENTION
[0007] In one aspect of the present invention, apparatus for
cooling bleed air on an aircraft may comprise: a source of cooling
fluid driven by an engine of the aircraft; a source of bleed air
driven by the engine; a heat exchanger configured to allow the
cooling fluid to pass over tubes through which the bleed air flows,
the heat exchanger having, a) a high-temperature zone constructed
from material with a first density, and b) a low-temperature zone
constructed from material with a second density lower than the
first density.
[0008] In another aspect of the present invention, a heat exchanger
may comprise: a high-temperature zone constructed from material
with a first density, and a low-temperature zone constructed from
material with a second density lower than the first density.
[0009] In still another aspect of the present invention, a method
for cooling hot fluid may comprise the steps: passing the hot fluid
through first tube segments of a heat exchanger; passing the hot
fluid through second tube segments of the heat exchanger directly
from the first tube segments, the second tube segments having a
lower temperature tolerance than the first tube segments; passing
cooling fluid over the first segments to cool the hot fluid to a
temperature within a range of temperature tolerance of the second
tube segments; and passing the cooling fluid over the second
segments to further cool the hot fluid.
[0010] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic diagram of a cooling system in
accordance with an embodiment of the invention;
[0012] FIG. 2 is a perspective, partially cut-away view of a heat
exchanger in accordance with a second embodiment of the
invention;
[0013] FIG. 3 is exploded view of a tube of the heat exchanger of
FIG. 2 in accordance with an embodiment of the invention; and
[0014] FIG. 4 is a flow chart of a method for cooling a hot fluid
in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The following detailed description is of the best currently
contemplated modes of carrying out the invention. The description
is not to be taken in a limiting sense, but is made merely for the
purpose of illustrating the general principles of the invention,
since the scope of the invention is best defined by the appended
claims.
[0016] Various inventive features are described below that can each
be used independently of one another or in combination with other
features.
[0017] The present invention generally provides a system by which
hot fluid such as bleed air may be cooled in a heat exchanger that
has some portions of its structure comprised of low density
materials.
[0018] Turning now to the description and with reference first to
FIG. 1, a schematic diagram may illustrate a cooling system 100
constructed in accordance with an exemplary embodiment of the
invention. An engine 102 of an aircraft (not shown) may be provided
with a high-pressure bleed air port 104, an intermediate-pressure
bleed air port 106 and a by-pass air port 108. A heat exchanger 110
may be positioned to receive hot fluid 111, such as bleed air, from
a hot-fluid inlet line 112 and to receive cooling fluid 113, such
as engine by-pass air, from a cooling-fluid inlet line 114. Cooled
bleed air may be discharged through a hot-fluid outlet line 116 and
by-pass air may be discharged through a cooling-fluid outlet line
118.
[0019] Referring now to FIG. 2, the heat exchanger 110 is
illustrated in a simplified cut-away format. In an exemplary
embodiment, the heat exchanger 110 may be constructed with multiple
zones. In the embodiment of FIG. 2, three zones are illustrated: a
high-temperature zone 120; a medium-temperature zone 122; and a
low-temperature zone 124. Hot fluid 111 or hot bleed air may enter
the heat exchanger 110 at an inlet end 126. The hot fluid 111 may
pass through a plurality of tubes 128 as cooling air 113 passes
over the tubes 128. Within the high-temperature zone 120 each of
the tubes 128 may comprise a high-temperature segment 132.
Similarly each of the tubes 128 may comprise a medium-temperature
segment 134 in the medium temperature zone 122 and a
low-temperature segment 136 in the low-temperature zone 124.
[0020] In an alternate exemplary embodiment, the heat exchanger 110
may comprise only two zones, the high-temperature zone 120 and the
low-temperature zone 124. In such a two zone configuration, the
tubes 128 may include only the high-temperature segment 132 and the
low-temperature segment 136.
[0021] In an exemplary embodiment the tubes 128 may be constructed
as brazed assemblies. As shown in FIG. 3, the segments 132 and 136
may be provided with at least one bell end 140. Non-bell ends 142
of the segments 134 may be inserted and brazed into the bell ends
140 of the segments 132. Similarly, the non-bell ends 142 of the
segments 134 may be inserted and brazed into the bell ends 140 of
the segments 136. The segments 132 may be constructed from
stainless steel or a nickel-based alloy so that they are capable of
withstanding high inlet temperature of 1200.degree. F. or higher.
As shown in FIG. 2, the segments 134 may be a distance D1 away from
the inlet end 126 of the heat exchanger 110. The distance D1 may be
great enough so that temperature of the hot fluid 111 may be
reduced from about 1200.degree. F. to about 1000.degree. F. The
segments 134 may be constructed from titanium or a titanium alloy
if exposed to temperatures of 1000.degree. F. or less. The segments
136 may be a distance D2 away from the inlet end 126 of the heat
exchanger 110. The distance D2 may be great enough so that
temperature of the hot fluid 111 may be reduced to about
600.degree. F. The segments 136 may be constructed from aluminum or
an aluminum alloy if exposed to temperature of 600.degree. F. or
less.
[0022] A multiple step brazing operation may be employed to
construct the heat exchanger 110. In a first brazing step, the
high-temperature segments 132 may be inserted into holes 151 of
hot-fluid inlet manifold 150. The inlet manifold 150 may be
constructed from material that can tolerate exposure to inlet
temperatures of the hot fluid 111 of 1200.degree. F. or higher. For
example, the inlet manifold 150 may be constructed from the same
type of material as that used for the segments 132.
High-temperature brazing filler 152 may be employed to produce
brazed connections between the segments 132 and the manifold 150.
The brazing filler 152 must be capable of maintaining a solid
connection when exposed to hot-fluid inlet temperatures of
1200.degree. F.
[0023] In a second brazing step, the segments 134 may be brazed
into a sub-assembly that includes the manifold 150 and the segments
132. As shown in FIG. 3, the ends 142 of the segments 134 may be
inserted into the bell ends 140 of the segments 132.
Medium-temperature brazing filler 154 may be employed to produce
brazed connections between the segments 132 and the segments 134.
The brazing filler 154 must be capable of maintaining a solid
connection when exposed to hot-fluid temperatures of about
1000.degree. F.
[0024] In a third brazing step, the segments 136 may be brazed into
a sub-assembly that includes the manifold 150, the segments 132 and
the segments 134. As shown in FIG. 3, the ends 142 of the segments
134 may be inserted into the bell ends 140 of the segments 136.
Low-temperature brazing filler 156 may be employed to produce
brazed connections between the segments 134 and the segments 136.
The brazing filler 156 must be capable of maintaining a solid
connection when exposed to hot-fluid temperatures of about
600.degree. F.
[0025] During the third brazing step, the segments 136 may be
brazed into holes 161 of a hot-fluid outlet manifold 160. The
outlet manifold 160 may be constructed from the same type of
material as the segments 136. The brazing filler 156 may be
employed to perform brazing of the outlet manifold 160.
[0026] The heat exchanger 110 may weigh less than a
high-temperature heat exchanger constructed completely from
stainless steel or nickel-based alloy. The segments 134, which may
be constructed from titanium or titanium alloy, may be less dense
than equivalent sections of tubing constructed from stainless steel
or nickel-based alloy. Similarly, the segments 136 and the outlet
manifold 160 which may be constructed from materials less dense
than equivalent elements constructed from stainless steel,
nickel-based alloy. For example, in one of the heat exchangers with
only two temperature zones, the segments 136 and the outlet
manifold 160 may be titanium or titanium based alloy. In one of the
heat exchangers 110 that is constructed with three temperature
zones, the low-temperature segments 136 and the outlet manifold may
be aluminum or aluminum based alloys. Through employment of these
lower density materials the light-weight heat exchanger 110 may be
particularly suited for weight-critical applications such as
aircraft or other aerospace vehicles.
[0027] It may be noted that the heat exchanger 110 may be
vulnerable to damage under conditions in which cooling fluid flow
is interrupted while high-temperature fluid passes through the heat
exchanger. Under these circumstances, the medium temperature
brazing filler 154 and the low-temperature brazing filler 156 may
be exposed to hot fluid temperatures of about 1200.degree. F.
However, these problematic conditions will not occur when the heat
exchanger 100 is employed as an element in the cooling system 100
of FIG. 1. In the cooling system 100, the hot fluid 111, i.e.,
bleed air, is produced only when the engine 102 is running. The
cooling fluid 113, in this case by-pass air, is continuously
produced whenever the engine 102 is running. Thus cooling fluid
flow will cease only when bleed air flow ceases. Consequently, the
light-weight heat exchanger 110 may be employed in the cooling
system 100 without concern for risk of damage that might result
from cessation of cooling fluid flow.
[0028] Referring now to FIG. 4, a flow chart 400 may illustrate a
method for cooling hot fluid. In a step 402, hot fluid may be
passed through first tube segments of a heat exchanger (e.g., hot
fluid 111 may be passed though tube segments 132 of the heat
exchanger 110). In a step 404, the hot fluid may be passed through
second tube segments of the heat exchanger directly from the first
tube segments, the second tube segments having a lower temperature
tolerance than the first tube segments (e.g. the hot fluid 111 may
be passed directly from the tube segments 132 directly into the
tube segments 134). In a step 406, cooling fluid may be passed over
the first segments to cool the hot fluid to a temperature within a
range of temperature tolerance of the second tube segments (e.g.,
the cooling fluid 113 may be passed over the tube segments 132). In
a step 408, the cooling fluid may be passed over the second
segments to further cool the hot fluid.
[0029] It should be understood, of course, that the foregoing
relates to exemplary embodiments of the invention and that
modifications may be made without departing from the spirit and
scope of the invention as set forth in the following claims.
* * * * *