U.S. patent application number 12/718748 was filed with the patent office on 2010-09-09 for thermal management device for a spacecraft.
This patent application is currently assigned to Thales. Invention is credited to Valerie Canton, Thierry Dargent, Julien Hugon, Patrick Hugonnot, Anne-Sophie Merino, Isabelle Nann.
Application Number | 20100223942 12/718748 |
Document ID | / |
Family ID | 41170941 |
Filed Date | 2010-09-09 |
United States Patent
Application |
20100223942 |
Kind Code |
A1 |
Merino; Anne-Sophie ; et
al. |
September 9, 2010 |
Thermal Management Device for a Spacecraft
Abstract
The invention relates to a thermal management device intended to
collect the heat dissipated by a group of dissipative equipment of
a spacecraft in an evaporation zone before discharging this heat to
cold space via a condensation zone, situated in the region of the
radiators. The evaporation zone and the condensation zone each
consist of at least one heat-exchange part comprising a network of
a plurality of compact heat-exchange elements distributed over
their respective heat-exchange surface and connected in series
and/or in parallel by the tubes of the thermal fluid circulation
means. A device such as this is particularly intended for
telecommunications satellites.
Inventors: |
Merino; Anne-Sophie;
(Mandelieu, FR) ; Hugon; Julien; (Montauroux,
FR) ; Canton; Valerie; (Mandelieu, FR) ;
Hugonnot; Patrick; (Mouans-Sartoux, FR) ; Dargent;
Thierry; (Auribeau Sur Saigne, FR) ; Nann;
Isabelle; (Cannes la Bocca, FR) |
Correspondence
Address: |
LARIVIERE, GRUBMAN & PAYNE, LLP
19 UPPER RAGSDALE DRIVE, SUITE 200
MONTEREY
CA
93940
US
|
Assignee: |
Thales
Neuilly Sur Seine
FR
|
Family ID: |
41170941 |
Appl. No.: |
12/718748 |
Filed: |
March 5, 2010 |
Current U.S.
Class: |
62/259.2 ;
62/498 |
Current CPC
Class: |
B64G 1/1007 20130101;
F28D 15/0266 20130101; F28D 15/00 20130101; B64G 1/503 20130101;
F28D 15/0275 20130101; B64G 1/506 20130101; B64G 1/50 20130101 |
Class at
Publication: |
62/259.2 ;
62/498 |
International
Class: |
F25D 23/00 20060101
F25D023/00; F25B 1/00 20060101 F25B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 6, 2009 |
FR |
0901031 |
Claims
1. Thermal management device intended to collect the heat
dissipated by a group of dissipative equipment of a spacecraft in
an evaporation zone before discharging this heat to cold space via
a condensation zone, spacecraft comprising a plurality of
structural panels and the thermal management device comprising
means of circulating thermal fluid connecting, in a closed loop, at
least the evaporation zone and the condensation zone, the
evaporation zone constituting a first heat-exchange surface for
exchanging heat, directly or indirectly via other heat-transfer
means, with the dissipative equipment, and the condensation zone
constituting a second heat-exchange surface for exchanging heat,
directly or indirectly via other heat-transfer means, with
radiators radiating into space, wherein the evaporation zone and/or
the condensation zone consists of at least one heat-exchange part
comprising a network of a plurality of compact heat-exchange
elements distributed over their respective heat-exchange surface
and connected in series and/or in parallel by the tubes of the
thermal fluid circulation means.
2. Thermal management device according to claim 1, wherein at least
one panel which is a somewhat poor conductor of heat in the
transverse direction perpendicular to its plane, comprises, on the
face internal to the craft, at least one heat-exchange part of the
evaporation zone and, on the face external to the craft, at least
one heat-exchange part of the condensation zone.
3. Thermal management device according to claim 1, comprising at
least a heat-exchange part of the evaporation zone is assembled
with heat-transfer means in contact on one side with the compact
heat-exchange elements and on another side with the dissipative
equipment.
4. Thermal management device according to claim 1, comprising at
least a heat-exchange part of the condensation zone is assembled
with heat-transfer means in contact on one side with the compact
heat-exchange elements and on another side with a radiator.
5. Thermal management device according to claim 1, wherein the
thermal fluid circulation means comprise a first and a second
circulation circuit, the heat-transfer means assembled with a
heat-exchange part of the evaporation zone having contact with at
least a first and a second compact heat-exchange element, the first
element being in contact with the first thermal fluid circulation
circuit and the second element being in contact with the second
circulation circuit.
6. Thermal management device according to claim 1, wherein the
thermal fluid circulation means comprise a first and a second
circulation circuit, the heat-transfer means assembled with a
heat-exchange part of the condensation zone having contact with at
least a first and a second compact heat-exchange element, the first
element being in contact with the first thermal fluid circulation
circuit and the second element being in contact with the second
circulation circuit.
7. Thermal management device according to claim 1, wherein the
evaporation zone and/or the condensation zone consists of a
plurality of heat-exchange parts and the thermal fluid circulation
means connect the said equipment in series and/or in parallel.
8. Thermal management device according to claim 1, wherein the
thermal fluid circulation loop also comprises an expansion zone
directly upstream of the evaporation zone and a compression zone
directly downstream of the evaporation zone.
9. Thermal management device according to claim 8, wherein the
thermal fluid circulation means comprise means for reversing the
direction in which the thermal fluid circulates so that the
condensation zone and the evaporation zone are interchanged.
10. Thermal management device according to claim 8, wherein the
expansion zone comprises a plurality of n pressure reducers to
provide temperature control for a plurality n of heat-exchange
parts of the evaporation zone at one or more different temperature
levels, the thermal fluid circulation means connecting the said
equipment in parallel.
11. Thermal management device according to claim 1, wherein the
means for circulating the thermal fluid is a mechanical pump.
12. Thermal management device according to claim 1, wherein the
means for circulating the thermal fluid is a capillary pump.
13. Thermal management device according to claim 1, wherein the
condensation zone also comprises heat-exchange means of the tubular
pipe type which are the thermal fluid circulation means configured
in series and/or in parallel and connected directly to a radiating
panel.
14. Thermal management device according to claim 1, wherein the
condensation zone also comprises heat-exchange means of the tubular
pipe type which are the thermal fluid circulation means configured
in series and/or in parallel and connected directly to dissipative
equipment.
15. Telecommunications satellite, comprising a thermal management
device according to claim 1.
16. Satellite according to claim 15, comprising a service module
and a communications module, wherein the external surfaces of the
structural panels of the modules support at least one radiator.
17. Satellite according to claim 15, wherein at least one radiator
is deployable.
Description
PRIORITY CLAIM
[0001] This application claims priority to French Patent
Application Number 09 01031, Thermal Management Device for a
Spacecraft, filed on Mar. 6, 2009.
FIELD OF THE INVENTION
[0002] The field of the invention is that of thermal management
devices for a group of dissipative equipment of a satellite and
more generally of a spacecraft.
BACKGROUND OF THE INVENTION
[0003] In general, satellites comprise a set of equipment intended
to perform the functions of the missions for which they are sent
into space, notably observation or telecommunications missions.
This equipment consumes and dissipates a substantial amount of
energy that has to be removed from the structure of the satellite
so that this equipment remains within a nominal temperature range.
To do that, the satellites are equipped with a thermal management
device notably comprising thermal fluid circulation pipes, commonly
known as heat pipes, and fluid loops allowing the heat of the
dissipative equipment to be transported to radiative elements that
radiate the thermal energy into space. In satellites, it is common
practice to use the structural panels on which to install the
radiative surfaces. In such configurations, the thermal energy that
can be removed is limited by the size of the structural panels.
Satellites are sized, amongst other considerations, in such a way
as to minimize the mass of the thermal management system, the
dimensions of the associated elements having to be limited so as to
allow them ultimately to be integrated into the satellite, the size
associated with the latter also having to be limited so that it can
be best integrated into the launcher. To improve the removal of
heat into space, it is known practice to install on the satellite
double-sided or single-sided deployable radiative surfaces which
are able to radiate at a higher or lower temperature in order to
remove some of the dissipated heat and thus guarantee that the
equipment is kept at admissible temperature levels. However, a
deployable system such as this makes the structure of the satellite
heavier and increases the size and complexity of the cooling device
through the presence of the control means and mechanisms for
deploying the panels.
[0004] A thermal management device installed on board a spacecraft
and described in patent application FR2912995A1 is known. That
device allows the dissipative equipment to be thermally decoupled
from their associated radiators and allows the areas of the
radiative heat-exchange surfaces to be varied according to the
amount of thermal energy to be removed into space by means of a
fluid circulation circuit comprising several hydraulic branches
that can be isolated from one another. That system has
disadvantages. The hydraulic circuit of the thermal management
device, particularly the condensation zone in contact with the
radiative surface directed towards space, is exposed to
micrometeorite attack. For that reason, it is known practice to
improve the reliability of the thermal management device either by
thickening the heat-exchange elements in the condensation zone and,
if necessary, those in the evaporation zone, or by installing an
entirely redundant hydraulic circuit. Both approaches carry a heavy
weight penalty. Furthermore, when the evaporation zone and the
condensation zone consist of continuous tubular systems, the
pressure drops may be not insignificant, notably when an all-series
configuration is given preference in order to avoid
thermo-hydraulic instabilities, and this dictates additional
compression work in order to achieve the high-temperature radiation
objective. This has an impact on the mass of the device, on the
energy consumption, and represents an integration constraint when
the evaporators and condensers have to have redundancy for
reliability reasons, that being true notably on account of the
multitude of tubes under the equipment. Finally, present-day
structural panels are thermally conductive which means that it is
inconceivable for equipment to be mounted on the internal face
thereof while at the same time expecting thermal energy to be
removed from the higher-temperature external face without having an
impact on the temperature level of the equipment opposite it inside
the satellite. That means that panels have to be superposed in
order to provide the necessary thermal decoupling or that
additional deployable structures have to be used, both solutions
significantly increasing the overall weight.
SUMMARY OF THE INVENTION
[0005] The objective of the invention is to achieve the reliability
of objectives of a satellite thermal management device while at the
same time optimizing its efficiency and minimizing its mass.
[0006] For that, the invention relates first of all, in general, to
a thermal management device intended to collect the heat dissipated
by a group of dissipative equipment of a spacecraft in an
evaporation zone before discharging this heat to cold space via a
condensation zone, spacecraft comprising a plurality of structural
panels and the thermal management device comprising means of
circulating thermal fluid connecting, in a closed loop, at least
the evaporation zone and the condensation zone, the evaporation
zone constituting a first heat-exchange surface for exchanging
heat, directly or indirectly via other heat-transfer means, with
the dissipative equipment associated with the structural panels and
the condensation zone constituting a second heat-exchange surface
for exchanging heat, directly or indirectly via other heat-transfer
means, with radiators radiating into space.
[0007] Advantageously, the evaporation zone and/or the condensation
zone consists of at least one heat-exchange part comprising a
network of a plurality of compact heat-exchange elements
distributed over their respective heat-exchange surface and
connected in series and/or in parallel by the tubes of the thermal
fluid circulation means.
[0008] The evaporation zone constitutes a first heat-exchange
surface that can be connected directly and/or indirectly by other
thermal means to the dissipative equipment. The condensation zone
constitutes a second heat-exchange surface that can be connected
directly and/or indirectly via other thermal means with the
radiative surfaces. The compact heat-exchange elements may be in
direct contact with the dissipative equipment or in contact with
the heat-transfer means connected to the equipment, such as heat
pipes and/or fluid loops.
[0009] What is meant by "compact heat-exchange element" are the
elements commonly known as evaporators in the evaporation zone and
condensers in the condensation zone.
[0010] The use of the compact heat-exchange elements makes it
possible to limit the area of surface to be protected from
micrometeorite activity, and therefore the mass of the exchangers
and to minimize the thermal gradient between the fluid circulating
through the evaporation zone and the dissipative equipment, on the
one hand, and between the fluid circulating in the condensation
zone and the radiative surfaces, on the other. Further, their
compactness means, on the one hand, that it is possible to limit
the lengths over which the fluid is circulated within them, and
therefore limit the pressure drops of the fluid. This may make it
possible to install all-series thermo-hydraulic networks in the
evaporation zone and in the condensation zone or at the very least
to limit the number of fluid branches in parallel in the said
heat-exchange zones.
[0011] In a preferred alternative form, at least one panel which is
a somewhat poor conductor of heat in the transverse direction
perpendicular to its plane, comprises, on the face internal to the
craft, at least one heat-exchange part of the evaporation zone and,
on the face external to the craft, at least one heat-exchange part
of the condensation zone. The said structural panel generally faces
into space and is chosen so that, through its sizing, it obeys the
other environmental constraints imposed by the mission. Thus,
certain heat-exchange elements of the evaporation zone may be
created at one of these panels, on the interior face, in or outside
the panel, while certain heat-exchange elements of the condensation
zone are created opposite in this same panel, to transmit the heat
to its exterior face thus able, if need be, to radiate at a higher
temperature than that of the heat-exchange elements of the
evaporation zone. In the case of radiation at a high temperature in
relation to the equipment operating temperature, the structural
panels of the satellite can therefore be kept as radiating panels,
thus reducing the overall mass balance of the thermal management
system by comparison with a solution involving other fixed or
deployable structures intended solely for radiating the thermal
energy at high temperature.
[0012] According to an alternative form, at least a heat-exchange
part of the evaporation zone is assembled with heat-transfer means
in contact on one side with the compact heat-exchange elements and
on another side with the dissipative equipment. The heat-transfer
means partially cover a surface by means of several elements
arranged on the said surface. These heat-transfer means may be heat
pipes and/or fluid loops.
[0013] This configuration makes it possible to limit the overall
surface area of the evaporation zone, broken down into as many
elements as required by the layout of the heat pipes and of the
dissipative equipment, which elements are connected together by
simple tubes. Such exchangers allow for effective heat exchange.
Further, their compactness makes it possible on the one hand to
limit the lengths over which fluid is circulated within them, and
therefore to limit the pressure drops of the fluid, and on the
other hand makes it possible to limit the areas of heat-exchange
elements directly or indirectly exposed to micrometeorite activity.
This reduces the mass of the additional thickness required for the
heat-exchange elements and therefore limits the mass of the thermal
management system. The layout of such locally-arranged compact
evaporators may allow the thermo-hydraulic network to be installed
in an all-series configuration or at the very least will make it
possible to limit the number of fluid branches in parallel in the
evaporation zone.
[0014] According to an alternative form, at least a heat-exchange
part of the condensation zone is assembled with heat-transfer means
in contact on one side with the compact heat-exchange elements and
on another side with a radiator. Likewise, the heat-transfer means
partially cover a surface by means of several elements arranged on
the said surface. These heat-transfer means may be heat pipes
and/or fluid loops.
[0015] This configuration makes it possible to limit the overall
surface area of the condensation zone, broken down into as many
elements as required by the layout of the heat pipes and of the
radiative surfaces, which elements are connected together by simple
tubes. Such exchangers allow for effective heat exchange. Further,
their compactness makes it possible on the one hand to limit the
lengths over which fluid is circulated within them, and therefore
to limit the pressure drops of the fluid, and on the other hand
makes it possible to limit the areas of heat-exchange elements
exposed to space and therefore exposed to micrometeorite activity.
The probability of impact is therefore limited. This reduces the
mass of the additional thickness required for the heat-exchange
elements facing out into space and therefore limits the mass of the
thermal management system. The layout of such locally-arranged
compact condensers may allow the thermo-hydraulic network to be
installed in an all-series configuration or at the very least will
make it possible to limit the number of fluid branches in parallel
in the condensation zone.
[0016] According to an alternative form of the invention, the means
of circulating the fluid in the various heat-exchange parts of the
evaporation zone have a series and/or parallel configuration. An
all-series configuration is preferable because it limits the
thermo-hydraulic instabilities between the various heat-exchange
parts. However, such a configuration is not always feasible from
the point of view of admissible pressure drops. In the parallel
configuration, it is possible to use elements to isolate branches
so that in the event of a fault, one heat-exchange part can be
isolated from the remainder of the system so that it will always be
possible to perform the mission in a downgraded mode. This
configuration may make it possible to dispense with the need for
redundancy in the evaporation zone and, in general, in the thermal
management device, thus affording a considerable weight saving.
[0017] According to an alternative form of the invention, the means
of circulating the fluid in the various thermal fluid circulation
circuits of the condensation zone have a series and/or parallel
configuration. In the parallel configuration it is possible to use
isolating elements so that if one thermal fluid circulation circuit
is lost, isolating it from the remainder of the thermal system
allows the mission to be performed in a downgraded mode. This
layout may make it possible to dispense with the need for
redundancy in the condensation zone and, in general, in the thermal
management device, thus affording a considerable weight saving.
[0018] According to an alternative form of the invention, the
thermal fluid circulation means comprise a first and a second
circulation circuit, the heat-transfer means assembled with a
heat-exchange part of the condensation zone having contact with at
least a first and a second compact heat-exchange element, the first
element being in contact with the first thermal fluid circulation
circuit and the second element being in contact with the second
circulation circuit.
[0019] According to an alternative form of the invention, the
thermal fluid circulation means comprise a first and a second
circulation circuit, the heat-transfer means assembled with a
heat-exchange part of the evaporation zone having contact with at
least a first and a second compact heat-exchange element, the first
element being in contact with the first thermal fluid circulation
circuit and the second element being in contact with the second
circulation circuit.
[0020] According to an alternative form of the invention, the
evaporation zone comprises heat-exchange elements of the tubular
pipe type which are the actual thermal fluid circulation means
configured in series and/or in parallel and connected directly to
dissipative equipment.
[0021] According to an alternative form of the invention, the
condensation zone comprises heat-exchange elements of the tubular
pipe type which are the actual thermal fluid circulation means
configured in series and/or in parallel and connected directly to a
radiative panel.
[0022] According to an alternative form, the evaporation zone
and/or the condensation zone consists of a plurality of
heat-exchange parts and the thermal fluid circulation means connect
the said equipment in series and/or in parallel.
[0023] According to an alternative form of the heat engine type,
the thermal fluid circulation loop also comprises an expansion zone
directly upstream of the evaporation zone and a compression zone
directly downstream of the evaporation zone. According to one
embodiment of this last alternative form, the thermal fluid
circulation means comprise means for reversing the direction in
which the thermal fluid circulates so that the condensation zone
and the evaporation zone are interchanged. According to any
embodiment of the last two alternative forms, the expansion zone
comprises a plurality of n pressure reducers to provide temperature
control Cora plurality n of heat-exchange parts of the evaporation
zone at one or more different temperature levels, the thermal fluid
circulation means connecting the said equipment in parallel. The
device of the invention, through the circulation means, proposes,
in this alternative form, to collect all or some of the heat
dissipated via satellite in a so-called evaporation zone associated
with the structural panels (main walls of the satellite and
internal racks), to compress the resultant steam leaving this zone
and thus raise the temperature of the fluid before condensing it at
the fixed or deployable radiators which will effectively, at high
temperature and by radiation, remove all of the energy to cold
space. The option of using thermo-hydraulically efficient compact
elements in the evaporation zone and the condensation zone means
that the levels of compression required in order to radiate at high
temperature are minimized, and this has an appreciable impact on
the energy consumption of the thermal management device, again
manifesting itself in weight saving.
[0024] According to one alternative form of the invention, the
solutions proposed hereinabove, apart from the heat engine
alternative forms, apply to any diphasic loop in which the means of
circulating the fluid is a mechanical pump, the loop having an
evaporation zone and a condensation zone.
[0025] According to one alternative form of the invention, the
solutions proposed hereinabove, apart from the heat engine
alternative forms, apply to any diphasic loop in which the means of
circulating the fluid is a capillary pump, the loop having an
evaporation zone and a condensation zone.
[0026] The invention is particularly intended for
telecommunications satellites. Advantageously, it comprises
heat-exchange parts in contact with the said staged dissipative
equipment. A satellite comprises a service module and a
communications module and advantageously the external surfaces of
the structural panels of the modules support at least one radiator.
In an alternative form, at least one radiator of the satellite is
deployable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The invention will be better understood and other advantages
will become apparent from reading the description which will
follow, which is given without implying any limitation and by
studying the attached figures among which:
[0028] FIG. 1 depicts a functional diagram of the hydraulic
architecture of a device to which the invention applies. It depicts
an architecture comprising an evaporation zone, a condensation
zone, and a means of circulating the heat-transfer or coolant
fluid.
[0029] FIG. 2 depicts a heat-exchange part of the evaporation zone
intended to be used in a device according to the invention.
[0030] FIG. 3 depicts a heat-exchange part of the condensation zone
intended to be used in a device according to the invention.
[0031] FIG. 4 depicts a diagram of a plurality of heat-exchange
elements configured in parallel and in series in a device according
to the invention for an evaporation zone or condensation zone.
[0032] FIG. 5 depicts a hydraulic architecture of the thermal
management device in a reverse circulation mode. The thermal fluid
is circulated by means of a compression system.
[0033] FIG. 6 depicts a hydraulic architecture of the thermal
management device in which the thermal fluid is circulated using a
mechanical pump.
[0034] FIG. 7 depicts a hydraulic architecture of the thermal
management device in which the thermal fluid is circulated by a
capillary pump.
[0035] FIG. 8 depicts a hydraulic architecture of the thermal
management device in which the thermal fluid is circulated using a
compressor. It depicts two modes of fluid circulation of the
thermal fluid which are the reverse of one another according to the
mode of operation of the device according to the invention.
[0036] FIG. 9 depicts a satellite structural panel comprising, on
the internal face, dissipative equipment in contact with part of
the evaporation zone and, on the external face, a part of the
condensation zone in contact with the radiative surface.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0037] FIG. 1 depicts a functional diagram of one embodiment of a
hydraulic architecture of the device to which the invention
applies. The thermal management device is made up of an evaporation
zone, of a condensation zone, of a zone for circulating the
heat-transfer or coolant fluid. The invention relates in particular
to the evaporation Z1 and condensation Z3 zones of the thermal
management device.
[0038] FIG. 2 illustrates an evaporation zone associated with a
part of a structural panel on which dissipative equipment is
mounted. This evaporation zone is made up of two thermal fluid
circulation circuits 11 and 12 in a series and/or parallel
configuration not specified in this illustration. Each thermal
fluid circulation circuit 11 and 12 of a heat-exchange part of the
evaporation zone is made up of a plurality of heat-exchange
elements 21 and 22 of compact type combined in series in this
illustration by connecting tubes (the elements are not necessarily
laid out in straight lines). The heat-exchange elements may be
combined entirely in series as indicated in FIG. 2, but also in
series/parallel in order to limit pressure drops and minimize mass.
The thermal fluid circulation circuits are connected in this
illustration by thermal means of the heat pipe type 310 and 311 to
the equipment distributed over a surface 40.
[0039] The heat pipe tubes 310 and 311 are preferably straight
tubes but may be elbowed for integration considerations; they may
either be incorporated into the panel or be mounted on the internal
face on which the equipment is to be mounted. The distribution of
heat pipes over the panel 40 is dependent on integration and mass
considerations. The compact heat-exchange elements 21 and 22 are
compact evaporators with high thermal energy transfer properties,
high coefficients of evaporation and low pressure drops. These
compact evaporators are generally parallelepipedal units with side
lengths ranging from a few centimeters to a few tens of centimeters
thus allowing the equipment to be mounted directly on top of them
if necessary. The use of a network of heat pipes is not compulsory
and the evaporation zone may be confined to thermal fluid
circulation circuits of the tubular pipe type with performance
optimized in terms of evaporation exchange coefficient, flux
density and pressure drop. In such cases, the thermal fluid
circulation circuits of the tubular pipe type are in direct contact
with the dissipative equipment, the number of passes under the
equipment will be defined as a function of the permissible thermal
gradient between the fluid and the equipment and by the
temperatures that are to be guaranteed. The tubes may be arranged
in series and in parallel to suit.
[0040] FIG. 3 illustrates a condensation zone associated with a
part of a radiating panel 50 radiating towards cold space. This
condensation zone is made up of two thermal fluid circulation
circuits 11 and 12 in a series and/or parallel configuration not
specified in this illustration. Each thermal fluid circulation
circuit of a heat-exchange part of the condensation zone 11 and 12
is made up of a plurality of heat-exchange elements 61 and 62 of
compact type combined in series in this illustration by connecting
tubes (the elements are not necessarily laid out in straight
lines). The heat-exchange elements may be combined entirely in
series as indicated in FIG. 3, but also in series/parallel in order
to limit pressure drops and minimize mass. In addition, an
isolating system allows one or more thermal fluid circulation
circuits to be operated according to the amount of thermal energy
that needs to be radiated into space or according to considerations
associated with failures (loss of one exchanger through
micrometeorite impact). The thermal fluid circulation circuits are
connected in this illustration by thermal means of the heat pipe
type 320 and 321 to the radiative panel 50.
[0041] The heat pipe tubes 320 and 321 are preferably straight
tubes but may be elbowed for integration considerations, they may
either be incorporated into the panel, when use is being made of a
structural panel, or mounted on a face in the case of an additional
radiative surface. The compact heat-exchange elements 61 and 62 are
compact condensers having high thermal energy transfer properties,
high condensation coefficients and low pressure drops. These
compact condensers are generally parallelepipedal units or
cylinders that may enclose the heat pipes at their end.
[0042] The heat-exchange parts of the evaporation zone and of the
condensation zone as described hereinabove may be used on at least
three hydraulic architectures of thermal management device (FIGS.
6, 7 and 8).
[0043] FIG. 4 illustrates an architecture that can be applied to
the evaporation and condensation zones. The n heat-exchange
elements of each zone 200, 201 and 202 are combined in parallel in
this figure in order to optimize the heating and mass budget. The
various zones 200, 201 and 202 are combined in series (200 and 201)
and in parallel 202. This architecture allows control over the
heat-exchange elements of the evaporation zone and therefore over
the dissipative equipment at various temperature levels. This
architecture allows the condensation zones to be balanced in order
to even out the energy that is to be removed by each panel to suit
the radiative environments. In an evaporation configuration, FIG. 4
depicts a diagram of an evaporation zone split into three
heat-exchange parts, each made up of n heat-exchange elements (n
may be different for each exchanger). The heat-exchange parts
corresponding to the zones 201 and 202 are positioned in series and
are therefore controlled to an identical temperature level, the
zone 202 in parallel may be controlled to a different temperature
level.
[0044] The heat-exchange elements have been laid out in a
parallel/series configuration (via fluid lines 11 and 12 here
proposed by way of example to run in parallel) which may differ
from the configuration proposed in the figure.
[0045] FIG. 5 illustrates a reversible architecture that allows the
direction of circulation of thermal fluid to be reversed so that
the condensation zone and the evaporation zone become interchanged.
This embodiment has the advantage that it reduces the heating
budget that the system requires. The thermal energy Q absorbed at
the radiative surfaces of zone Z3 (IR flux, solar flux, etc.) can
thus be used to keep the dissipative equipment in contact with the
zone Z1 at acceptable temperature levels in transfer phases and
also in orbit. An isolating system allows the direction of
circulation of the loop to be reversed. This reversible
architecture is particularly intended for the architecture
described in FIG. 8.
[0046] FIG. 6 illustrates an embodiment of thermal management
device. This architecture comprises, connected in succession in
series in a closed thermal fluid circulation loop, an evaporation
zone Z1, a condensation zone Z3, a means 4 of controlling the
temperature of the loop, commonly known as a thermo-hydraulic
reservoir, and a means 3 of circulating the heat transfer fluid
using a mechanical pump. The circulation circuits 401 of the
evaporation zone Z1, of the condensation zone Z3 and between these
two zones are preferably circuits for the diphasic circulation of
the thermal fluid. The circulation circuits 402 between the
condensation zone and the evaporation zone are preferably
monophasic circulation circuits.
[0047] FIG. 7 illustrates another embodiment of a thermal
management device. This architecture comprises, connected in
succession in series in a closed thermal fluid circulation loop, an
evaporation zone Z1 and a condensation zone Z3. The fluid is
circulated by means of a capillary pump in the evaporation zone.
The circulation circuits 501 of the evaporation zone, of the
condensation zone and between these two zones are preferably
circuits for the diphasic circulation of the thermal fluid. This
architecture allows a greater quantity of heat to be collected on
the surfaces covering the dissipative equipment and also allows a
large amount of thermal energy to be radiated at the radiative
surfaces. The circulation circuits 502 between the condensation
zone and the evaporation zone are preferably monophasic circulation
circuits.
[0048] FIG. 8 illustrates another embodiment of a thermal
management device. This architecture comprises, connected in
succession in series in a closed thermal fluid circulation loop, an
evaporation zone Z1, a compression zone Z2, a condensation zone Z3
and an expansion zone Z4. Two modes of circulating the thermal
fluid are depicted. A first mode, in which the circulation of the
fluid is depicted in solid line, describes the architecture of the
heat engine that allows the thermal energy Q to be removed, as a
solid arrow in solid line, from the dissipative equipment into
space. The zone Z1 is the evaporation zone and the zone Z3 is the
condensation zone. The second mode, in which the circulation of the
fluid is depicted in dotted line, describes the architecture of the
heat engine in reverse circulation, as described by FIG. 5
hereinabove. The thermal energy Q absorbed, in a solid arrow drawn
in dotted line, at the radiative surfaces of zone Z3 (IR flux,
solar flux, etc.) can thus be used to keep the dissipative
equipment in contact with the zone Z1 at acceptable temperature
levels during transfer phases and also in orbit. The expansion zone
comprises one or more pressure reducers in series and/or in
parallel to control parts of the evaporation zone at different
temperature levels. For example, the number of pressure reducers
used may be dependent on the number of branches of evaporator parts
in parallel and on the associated temperature ranges. For example,
pressure reducers of the capillary or thermostatic type may be
used. The compression zone comprises one or more compressors. The
thermal fluid used for this hydraulic architecture is rather of the
coolant type.
[0049] FIG. 9 depicts a cross-sectional diagram of a satellite
depicting part of the structure of a satellite 78 with one of the
structural panels 74 comprising, on the internal surface, apart 751
of the evaporation zone in contact with dissipative electronic
equipment 761 and 762 supported by the panel 74, which is a poor
conductor perpendicular to its plane, and on the external surface a
part 73 of the condensation zone in contact with a part of the
radiative surface 72. The structural panel 74 is, for example, the
north-facing panel of a telecommunications satellite. A
telecommunications satellite is usually made up of panels commonly
known as north, south, east, west, earth and anti-earth. All these
panels may have an internal face with part of the evaporation zone
and an external face with part of the condensation zone like the
panel 74 depicted in FIG. 8. In addition, the satellite comprises,
inside the casing 78, electronic equipment 763 and 764 arranged in
racks and decoupled from the panels of the satellite. Parts of the
evaporation zone 752 and 753 have the function of collecting the
thermal energy generated by the dissipative equipment. The
radiative surface is directed out into space. The radiative surface
is covered with several protective layers 71. The layers improve
protection against micrometeorite attack but do not prevent
conductive heat transfer between the condensation zone and the
radiation zone. The layer 70 covering the radiative surfaces is a
means of emitting the dissipated energy while at the same time
limiting the absorption of external thermal flux (solar flux and
the like). It may be made up of mirrors. The thermal fluid
circulation means 79 circulate within the parts 751, 752 and 753 of
the evaporation and condensation zones made up of one or more
heat-exchange parts. The dissipative equipment positioned in racks
inside the satellite and the dissipative equipment positioned on
the structural panels is associated with one and the same thermal
fluid hydraulic circuit by means of circuit branches in parallel
and/or series.
[0050] A telecommunications satellite comprises a module known as
the service module and a communication module. The panels of these
two modules may be arranged with the thermal management device with
part of the evaporation zone on the internal face and part of the
condensation zone on the external face. The thermal gradient
between the faces of the panels is high while the thermal gradient
longitudinally along the face of the panels is practically
zero.
[0051] One advantage of the device according to the invention is
the use of a thermal energy transfer architecture in which the
evaporation zone is thermally decoupled from the condensation zone,
these zones being structurally connected to the same panels.
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