U.S. patent application number 16/007201 was filed with the patent office on 2019-12-19 for sublimator having integrally formed closure bars on a porous plate.
The applicant listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Jesse Joseph STIEBER, Jeremy M. STRANGE, Mark A. ZAFFETTI.
Application Number | 20190383527 16/007201 |
Document ID | / |
Family ID | 68839786 |
Filed Date | 2019-12-19 |
United States Patent
Application |
20190383527 |
Kind Code |
A1 |
ZAFFETTI; Mark A. ; et
al. |
December 19, 2019 |
SUBLIMATOR HAVING INTEGRALLY FORMED CLOSURE BARS ON A POROUS
PLATE
Abstract
A sublimator includes a porous plate having a first surface
comprising a low pressure side and a second surface comprising a
high pressure side that allows a sublimate to move through the
porous plate from the high pressure side to the low pressure side,
and wherein the second surface defines a primary heat transfer
surface. The sublimator also includes: a plurality of secondary
heat transfer surfaces integrally formed on the primary heat
transfer surface to facilitate flow and evenly distribute the
sublimate across the high pressure side of the porous plate; and
one or more closure bars formed integrally formed along an outer
end of the plate and formed by an advanced manufacturing
technique.
Inventors: |
ZAFFETTI; Mark A.;
(Suffield, CT) ; STRANGE; Jeremy M.; (Windsor,
CT) ; STIEBER; Jesse Joseph; (Avon, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
|
|
Family ID: |
68839786 |
Appl. No.: |
16/007201 |
Filed: |
June 13, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28F 13/003 20130101;
F28F 3/025 20130101; F28D 21/0015 20130101; F25B 19/00 20130101;
F28D 1/0366 20130101; F28D 2021/0064 20130101; F25D 31/00 20130101;
F28F 2275/06 20130101 |
International
Class: |
F25B 19/00 20060101
F25B019/00; F28F 13/00 20060101 F28F013/00 |
Claims
1. A sublimator comprising: a porous plate having a first surface
comprising a low pressure side and a second surface comprising a
high pressure side that allows a sublimate to move through the
porous plate from the high pressure side to the low pressure side,
and wherein the second surface defines a primary heat transfer
surface; a plurality of secondary heat transfer surfaces integrally
formed on the primary heat transfer surface to facilitate flow and
evenly distribute the sublimate across the high pressure side of
the porous plate; and one or more closure bars formed integrally
formed along an outer end of the plate and formed by an advanced
manufacturing technique.
2. The sublimator of claim 1, wherein the advanced manufacturing
technique is one of: laser-sintering, stereolithography, and fused
deposition.
3. The sublimator according to claim 1, wherein the plurality of
secondary heat transfer surfaces comprise a plurality fins
extending outwardly from the primary heat transfer surface.
4. The sublimator according to claim 3, further comprising: an
intermediate plate having a first side and a second side facing
opposite the first side, wherein the first side is spaced apart
from the high pressure side of the porous plate and contacts the
one or more closure bars to define a sublimate chamber, and wherein
the second side at least partially encloses a fluid chamber
configured to cool a fluid within the fluid chamber.
5. The sublimator according to claim 4, further including an inlet
to direct sublimate into the sublimate chamber to flow across the
primary and secondary heat transfer surfaces.
6. The sublimator according to claim 4, further including a
sublimate supply in fluid communication with the inlet to replenish
sublimate that sublimates from the low pressure side of the porous
plate into an external environment.
7. The sublimator according to claim 1, wherein the plurality of
secondary heat transfer surfaces comprise a plurality of fins
placed in a predetermined arrangement to optimize heat sink with
heat flux input.
8. The sublimator according to claim 1, wherein a height of the
plurality of secondary heat transfer surfaces is the same as a
height of the one or more closure bars.
9. A sublimator comprising: a sublimate chamber having a first side
and a second side; a fluid chamber positioned on the first side of
the sublimate chamber, wherein the fluid chamber is configured to
receive a fluid to be cooled; and a porous plate having a first
surface comprising a low pressure side and a second surface
comprising a high pressure side, wherein the high pressure side is
positioned on the second side of the sublimate chamber such that
sublimate can move through the porous plate from the high pressure
side to the low pressure side, and wherein the second surface of
the porous plate defines a primary heat transfer surface, and
wherein the porous plate includes a plurality of secondary heat
transfer surfaces integrally thrilled on the primary heat transfer
surface to facilitate flow and evenly distribute the sublimate
across the high pressure side of the porous plate, and wherein the
porous plate includes one or more closure bars formed integrally
formed along an outer end of the plate and formed by an advanced
manufacturing technique.
10. The sublimator according to claim 9, wherein the advanced
manufacturing technique is one of: laser-sintering,
stereolithography, and fused deposition.
11. The sublimator according to claim 9, wherein the plurality of
secondary heat transfer surfaces comprise a plurality fins
extending outwardly from the primary heat transfer surface.
12. The sublimator according to claim 9, wherein the plurality of
secondary heat transfer surfaces comprise a plurality of fins
placed in a predetermined arrangement to optimize heat sink with
heat flux input.
13. The sublimator according to claim 9, wherein a height of the
plurality of secondary heat transfer surfaces is the same as a
height of the one or more closure bars.
14. A method of making a sublimator comprising the steps of:
providing a porous plate having a first surface comprising a low
pressure side and a second surface comprising a high pressure side
such that sublimate is configured to move through the porous plate
from the high pressure side to the low pressure side, and wherein
the second surface defines a primary heat transfer surface; and
integrally forming at least one closure bars on the porous plate by
using an additive manufacturing.
15. The method of claim 14, further comprising: integrally forming
with an additive manufacturing process a plurality of secondary
heat transfer surfaces on the primary heat transfer surface to
facilitate flow and evenly distribute sublimate across the high
pressure side of the porous plate.
16. The method of claim 14, wherein the additive manufacturing
process is one of: laser-sintering, stereolithography, and fused
deposition.
Description
BACKGROUND
[0001] Exemplary embodiments pertain to the art of sublimator heat
exchangers and, in particular, to a sublimator heat exchanger
having structural members formed by an advance manufacturing
technique.
[0002] A sublimator takes a fluid to be cooled and transfers the
heat contained therein to a sublimate that is sublimated. A
sublimator typically includes a metallic porous plate that is
exposed to space vacuum on one side. It is supplied with a
sublimate such as expendable feed-water on the other side. In
operation, the feed-water freezes on the porous plate surface, and
the vacuum side progressively sublimes water from this ice to the
vacuum of space as waste heat is introduced into the plate.
[0003] Traditionally, the porous plate through which the sublimate
sublimates includes plurality of fins that are individually
attached to the porous plate. Depending upon the application, there
can be several thousand fins that are attached to the porous plate
with each fin segment being, incrementally spot welded to the
porous plate in many locations. Further, the porous plate will
include One, or more closure bars disposed on outer sides of the
fins. The closure bars provide support to additional portions of
the sublimator and may serve to define an outer boundary for the
sublimate. The closure bars are also spot welded on the porous
plate.
[0004] The spot welding is labor intensive and time consuming.
Further, maintaining weld quality through this process requires
constant tool maintenance and frequent quality inspections which
increases overall manufactory cost.
BRIEF DESCRIPTION
[0005] Disclosed is a sublimator that includes: a porous plate
having a first surface comprising a low pressure side and a second
surface comprising a high pressure side such that a sublimate is
configured to move through the porous plate from the high pressure
side to the low pressure side, and wherein the second surface
defines a primary heat transfer surface; a plurality of secondary
heat transfer surfaces integrally formed on the primary heat
transfer surface to facilitate flow and evenly distribute sublimate
across the high pressure side of the porous plate; and one or more
closure bars formed integrally formed along an outer end of the
plate and formed by an advanced manufacturing technique.
[0006] In another embodiment, a sublimator is disclosed that
includes: a sublimate chamber having a first side and a second
side; a fluid chamber positioned on the first side of the sublimate
chamber, wherein the fluid chamber is configured to receive a fluid
to be cooled; and a porous plate having a first surface comprising
a low pressure side and a second surface comprising a high pressure
side. The high pressure side is positioned on the second side of
the sublimate chamber such that sublimate is configured to move
through the porous plate from the high pressure side to the low
pressure side, the second surface of the porous plate defines a
primary heat transfer surface, the porous plate includes a
plurality of secondary heat transfer surfaces integrally formed on
the primary heat transfer surface to facilitate flow and evenly
distribute sublimate across the high pressure side of the porous
plate, and the porous plate includes one or more closure bars
formed integrally formed along an outer end of the plate and formed
by an advanced manufacturing technique
[0007] In any embodiment of a sublimator previously disclosed, the
advanced manufacturing technique is one of: laser-sintering,
stereolithography, and fused deposition.
[0008] In any embodiment of a sublimator previously disclosed, the
plurality of secondary heat transfer surfaces comprise a plurality
fins extending outwardly from the primary heat transfer
surface.
[0009] In any embodiment of a sublimator previously disclosed, the
sublimator further includes: an intermediate plate having a first
side and a second side facing opposite the first side, wherein the
first side is spaced apart from the high pressure side of the
porous plate and contacts the one or more closure bars to define a
sublimate chamber, and wherein the second side at least partially
encloses a fluid chamber configured to cool a fluid within the
fluid chamber.
[0010] In any embodiment of a sublimator previously disclosed, the
sublimator further includes an inlet to direct the sublimate into
the sublimate chamber to flow across the primary and secondary heat
transfer surfaces.
[0011] In any embodiment of a sublimator previously disclosed, the
sublimator further includes a sublimate supply in fluid
communication with the inlet to replenish sublimate that sublimates
from the low pressure side of the porous plate into an external
environment.
[0012] In any embodiment of a sublimator previously disclosed, the
plurality of secondary heat transfer surfaces comprise a plurality
of fins placed in a predetermined arrangement to optimize heat sink
with heat flux input.
[0013] In any embodiment of a sublimator previously disclosed, a
height of the plurality of secondary heat transfer surfaces is the
same as a height of the one or more closure bars.
[0014] In any embodiment of a sublimator previously disclosed, the
plurality of secondary heat transfer surfaces comprise a plurality
of fins placed in a predetermined arrangement to optimize heat sink
with heat flux input.
[0015] In any embodiment of a sublimator previously disclosed, a
height of the plurality of secondary heat transfer surfaces is the
same as a height of the one or more closure bars.
[0016] In one embodiment a method of making a sublimator is
disclosed. The method includes: providing a porous plate having a
first surface comprising a low pressure side and a second surface
comprising a high pressure side such that sublimate is configured
to move through the porous plate from the high pressure side to the
low pressure side, and wherein the second surface defines a primary
heat transfer surface; and integrally forming at least one closure
bars on the porous plate by using an additive manufacturing.
[0017] In one embodiment, any method previously disclosed further
includes integrally forming with an additive manufacturing process
a plurality of secondary heat transfer surfaces on the primary heat
transfer surface to facilitate flow and evenly distribute sublimate
across the high pressure side of the porous plate.
[0018] In one embodiment, in any method previously disclosed the
additive manufacturing process is one of: laser-sintering,
stereolithography, and fused deposition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The following descriptions should not be considered limiting
in any way. With reference to the accompanying drawings, like
elements are numbered alike:
[0020] FIG. 1 shows a schematic representation of a sublimator
according to one embodiment;
[0021] FIG. 2A is an exploded view of a conventional porous plate
that includes welded fins and closure bars;
[0022] FIG. 2B shows a portion of a completed version of the porous
plate of FIG. 2A; and
[0023] FIG. 3 shows a portion of a porous plate according to one
embodiment.
DETAILED DESCRIPTION
[0024] A detailed description of one or more embodiments of the
disclosed apparatus and method are presented herein by way of
exemplification and not limitation with reference to the
Figures.
[0025] FIG. 1 shows a sublimator 10 that includes a sublimate
chamber 12 having a first side 14 and a second side 16. A fluid
chamber 18 is positioned on the first side 14 of the sublimate
chamber 12. The fluid chamber 18 is configured to receive a fluid
20 to be cooled. A porous plate 22 has a first surface 24
comprising a low pressure side Lp and a second surface 26
comprising a high pressure side Hp. The high pressure side Hp is
positioned on the second side 16 of the sublimate chamber 12 such
that sublimate 28 is configured to move through the porous plate 22
from the high pressure side Hp to the low pressure side Lp. The
second surface 26 of the porous plate 22 defines a primary heat
transfer surface. The porous plate 22 also includes a plurality of
secondary heat transfer surfaces 30 (or fins) formed on the primary
heat transfer surface to facilitate flow and evenly distribute
sublimate across the high pressure side Hp of the porous plate 22.
As disclosed more fully below, the porous plate 22 also includes
closure bars 52 formed on one or-more outer sides of the porous
plate 22. The closure bars 52 and the fins 30 are shown as being
formed of the same material but that is not required. Also, the
height of the closure bars 52 and the fins 30 can be different from
one another.
[0026] The fluid chamber 18 comprises an area that is enclosed by a
housing 32 that includes an intermediate plate portion 34 that is
located between the sublimate chamber 12 and the fluid chamber 18.
While a single fluid chamber 18 and a single sublimate chamber are
shown, it should be understood that there could be additional fluid
chambers 18 and additional sublimate chambers 12. This will be
discussed in greater detail below.
[0027] In one embodiment, the closure bars 52 contact the
intermediate plate 34 and define outer boundaries of the sublimate
chamber 12.
[0028] The sublimator 10 includes an inlet 40 to direct the
sublimate 28 into the sublimate chamber 12 to flow across the
primary and secondary heat transfer surfaces. A sublimate supply 42
is in fluid communication with the inlet 40 to replenish sublimate
that sublimates from the low pressure side Lp of the porous plate
22 into an external environment E, such as outer space for example.
A header 44 fluidly connects the inlet 40 to the sublimate chamber
12.
[0029] The sublimator 10 is used with a sublimate 28 that has a
triple point where equilibrium of vapor, liquid, and solid will
occur at a predetermined temperature or pressure and there is
available an environment at or below this condition in one example,
the sublimate 28 comprises water: however, other types of sublimate
could also be used. The sublimate 28 is directed into the sublimate
chamber 12 from the pressurized supply 42. The sublimate 28 then
passes through the porous material that forms the porous plate 22
and freezes when exposed to the low pressure side Lp to form a
layer of ice 50 that blocks further sublimate 28 from exiting the
low pressure side Lp of the porous plate 22.
[0030] The sublimate 28 sublimates into the external environment E
as heat is conducted to the porous plate 22 due to the heat
exchange between the fluid 20 to be cooled and the sublimate 28 in
the sublimate chamber 12. As the sublimate 28 sublimates away from
the porous plate 22 and the solid sublimate becomes depleted, more
sublimate is automatically used to replenish the porous plate
22.
[0031] In one example, the porous plate 22 is comprised of a
stainless steel material having a pore size of approximately 0.5
microns. Other types of porous materials could also be used:
however, the material needs to have a porous characteristic that
facilitates formation of the necessary layer of ice 50 for
sublimation. Each pore essentially becomes plugged with ice that
has a surface exposed to the outer space environment E. As
sublimation occurs at this surface, the thickness of the layer of
ice 50 is reduced until it can no longer support the internal
pressure within the chamber 12 and the sublimate will begin to pass
into the external environment E. When the sublimate is exposed to
this lower pressure level below its triple point, the sublimate
freezes and reforms the ice.
[0032] In the example shown, the entire high pressure side Hp of
the porous plate 22 is overlaid on the sublimate chamber 12 to
provide maximum exposure. The fins 30 formed on the porous plate
further enhance flow and improve distribution across and through
the porous plate 22. This allows the formation of a uniform sheet
of ice 50 across the low pressure side Lp of the porous plate 22.
The fluid 20 that is to be cooled transmits heat through the
intermediate plate portion 34 and through the sublimate 28 and
eventually into the porous plate 22. The heat sublimates the ice at
a rate that is directly proportional to the heat load and the fluid
20 to be cooled is discharged at a temperature that is lower than
when the fluid entered the fluid chamber 18.
[0033] As discussed above, while only a single fluid chamber or
passage 18 is shown in FIG. 1, the sublimator 10 can include
multiple fluid passages in parallel. Adjacent to each fluid passage
18 is a sublimate passage or chamber 12, which are fed by a common
inlet header 44. The sublimate flows in via the header 44 and exits
the sublimator either by sublimation or evaporation depending on
the "sink" temperature. The "sink" is the porous plate 22, and as
the range of heat flux into the porous plate 22 varies, the heat
rejection capability of the sublimator moves coincidently. This
relationship drives the demand for efficient integral construction
of the sublimate passage or chamber 12 with respect to the primary
(porous plate surface) and secondary (protrusions/fins) heat
transfer surfaces. Proper layout of the secondary heat transfer
surfaces is essential to balancing the heat flux to heat sink
temperature relationship. Maintaining a tight control band on the
sink capacity will produce a fleet of sublimators with minimal unit
to unit variability in heat rejection capability.
[0034] With reference now to FIGS. 2A and 2B, prior art fins 100
are formed as part of a fin plate 102 that is spot welded to the
porous plate 22. Spot welding is a manufacturing method which leads
to variability in the overall heat transfer effectiveness of a
sublimator due to its inherent quality instability. The variability
of quality in the small spot welds effects the ability of heat to
transfer from the fluid to be cooled to the sublimate within the
porous plate. This poor connection equates to a larger device for a
given heat load. The porous plate also has closure bars 104 that
are brazed to the porous plate 22. The process of both spot welding
and brazing are labor intensive, time consuming and requires
constant tool maintenance to stay within the required quality
tolerance.
[0035] With reference now to FIG. 3, as disclosed herein, the
porous plate 22 has one or more of the closure bar 204 and the fins
30 formed by directly thereon by an advanced manufacturing
technique. Such advanced manufacturing, techniques can include, for
example, additive manufacturing. In that regard, a variety of
additive manufacturing methods can be used to produce the
integrally formed fins 30 and closure bar 204. The process is used
to form or grow these elements directly on the porous plate 22.
Processes such as laser-sintering, stereolithography, and fused
deposition modeling are just some of the example processes that
could be used to integrally form the elements the porous plate. The
shape, size, location and density of the elements can be varied as
needed to produce the optimum heat sink characteristics to
precisely match the heat flux input.
[0036] The term "about" is intended to include the degree of error
associated with measurement of the particular quantity based upon
the equipment available at the time of filing the application.
[0037] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the present disclosure. As used herein, the singular forms "a",
"an" and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, element components, and/or
groups thereof.
[0038] While the present disclosure has been described with
reference to an exemplary embodiment or embodiments, it will be
understood by those skilled in the art that various changes may be
made and equivalents may be substituted for elements thereof
without departing from the scope of the present disclosure. In
addition, many modifications may be made to adapt a particular
situation or material to the teachings of the present disclosure
without departing from the essential scope thereof. Therefore, it
is intended that the present disclosure not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this present disclosure, but that the present
disclosure will include all embodiments falling within the scope of
the claims.
* * * * *