EP2861928B1 - Temperature control device - Google Patents

Description

The present invention relates to a satellite according to the preamble of claim 1. Such a satellite is known from the document US 2008/0289801 .

Preamble and prior art

By thermal control is meant maintaining a given equipment at a temperature within a predetermined range. The heat produced by one or more heat sources must be collected and transported to areas where it can escape into heat sinks (radiators).

Such a requirement is particularly critical for electronic equipment embedded on satellite. Indeed, said equipment is highly dissipative and must be maintained in a given temperature range despite significant variations in the thermal environment of the satellite and an inability to evacuate heat by natural or forced convection.

For example, within a satellite coexist radiative walls said radiator panels, or radiators, which dissipate heat by radiation to the cold space, and walls carrying the dissipative electronic equipment, said equipment panels. The heat dissipated by the equipment is collected at the equipment door panels and must be evacuated to the radiator panels.

It is understood that the thermal coupling between equipment panels and radiator panels is critical to ensure the proper evacuation of the heat dissipated by the electronic equipment. This thermal coupling is also complex to achieve because of the limited space available within the satellite, related to the size of the equipment and their geometry. Furthermore, the thermal control system must meet conflicting needs, because it must both ensure efficient collection of the heat produced by the dissipative equipment, and allow efficient thermal transport over a potentially large distance between the door panels. equipment and panels radiators.

Heat pipes are conventionally used to provide the thermal transport function.

It is recalled that a heat pipe uses the phase change of a fluid to ensure the collection of heat in a hot place, and its transfer as a vapor to a cold place. A tubular heat pipe is conventionally composed of a closed tube in which the liquid and gaseous phases of the same fluid maintained under pressure coexist. The heat pipe makes it possible to store the heat by evaporation and to restore it by condensation of the fluid.

A first part of the heat pipe, called hot zone (evaporator), is, for this purpose, disposed in the vicinity of a heat source, such as for example a dissipative element of thermal energy. At this point, the liquid contained in the heat pipe vaporizes by absorbing heat. The steam thus created propagates inside the heat pipe to another part of the heat pipe, called cold zone (condenser), disposed in the vicinity of a heat sink. The gas then condenses by returning the previously absorbed heat. The necessary circulation of the liquid between the cold zone and the hot zone is commonly done by capillarity, which is facilitated by the use of grooves, lattices, arteries or metal foam disposed on the inner surface of the heat pipe.

A heat source is typically an equipment or equipment panel. A typical heat sink is a radiator panel.

A heat pipe can be in thermal contact with several heat sources and several heat sinks.

The duct of a tubular heat pipe (see Figures 1a and 1b ) is a cylindrical tube whose inner wall is grooved, for example by extrusion, thereby creating the capillary structure through which the liquid passes. A soleplate, contiguous to the tube heat pipe over a part of its length, promotes thermal contact between the tubular heat pipe and heat sources and / or heat sinks, through a flat mounting interface. The typical length of a tubular heat pipe embedded on a satellite for cooling panels is from a meter to a few meters and its diameter from one to a few centimeters.

In the case of an application considered here, the heat produced by the equipment mounted on a satellite panel must be transported to another panel of the satellite, or to another part of the same panel (it is also possible to have a heat pipe which spreads over the radiator heat by doing at the same time interface with one or more dissipative equipment), where it will be dissipated.

This is the case for example when the equipment carrier panel is in the sun (it radiates less and therefore evacuates heat less well) and another panel is in the shade (favorable case for radiating heat). In this case, the tubular heat pipes can be extended so that they carry the heat from one panel to the other (they are bent at the intersection). The heat is effectively removed when at least one of the two panels is in the shade (or at low solar incidence).

In the case of the thermal control of equipment panels on board satellites, the collection of heat at the level of equipment is done by heat exchange between a number of tubular heat pipes and the equipment.

In this case, the main limitation observed is the heat collection capacity by the heat pipes for a given heat flow density. With a given heat pipe profile, the number of heat pipes to be positioned is sized by the heat collection and in this case, the heat pipe network is oversized for the heat transport from one panel to another and / or the diffusion of heat. heat on a panel, resulting in a large surplus of mass.

On the other hand, the performance of the heat exchange at the heat pipe is proportional to the heat exchange surface internal to the heat pipe (grooves for example) and therefore to minimize the thermal gradients it is sometimes necessary to multiply the number of heat pipes.

Presentation of the invention

• au moins une zone d'échange de chaleur comportant un caloduc configuré sous la forme d'une enveloppe mince (c'est à dire une surface d'échange importante avec une épaisseur très faible, typiquement au moins dix fois plus faible, que les autres dimensions), ladite zone d'échange étant dite "enceinte plate" (qui peut se présenter sous forme de plaque en une, deux ou trois dimensions),
• au moins une zone de transport de chaleur configurée sous la forme d'au moins un caloduc tubulaire, ledit caloduc tubulaire étant dit "tube", et
• au moins un noeud de connexion entre l'enceinte plate et le tube, ledit noeud de connexion présentant une continuité de capillarité entre l'enceinte plate et le tube.

The invention relates to a satellite according to claim 1. In other words, it is a satellite with a thermal regulation device implementing a thermal enclosure containing a two-phase fluid, said device comprising:

• at least one heat exchange zone comprising a heat pipe configured in the form of a thin envelope (that is to say a large exchange surface with a very small thickness, typically at least ten times lower, than the other dimensions), said exchange zone being said "flat enclosure" (which can be in the form of a plate in one, two or three dimensions),
• at least one heat transport zone configured in the form of at least one tubular heat pipe, said tubular heat pipe being said to be "tube", and
• at least one connection node between the flat enclosure and the tube, said connection node having a continuity of capillarity between the flat enclosure and the tube.

The capillary dimension of the grooves, pores, cells, lattices, etc. which ensure the flow of the fluid in liquid form through the node is of substantially the same size (in a ratio of 0.5 to 2) as the capillary dimension of the tubular heat pipe.

Advantageously, in the case of several tubes connected to the same flat enclosure, said tubes have steam ducts whose sum of the passage sections is substantially equal to the vapor passage section of said flat enclosure, in order to facilitate the flow of steam between the flat enclosure and the tubes.

It will be understood that the device in the satellite of the invention makes it possible to independently solve the dimensioning adapted to the heat transport, and the dimensioning adapted to the heat exchange, with a single system. The device uses on the one hand a tubular heat pipe (tube) without heat exchange function for the heat transport function, this tubular heat pipe being of small dimensions, and capable of accepting a geometry dictated by the arrangement and the geometry spaces left free between equipment panels and radiators.

On the other hand, the device uses an extended cavity heat pipe, here called flat enclosure, disposed under the electronic equipment, for the heat exchange function.

The device comprises a capillary connection between the at least one tube and the flat enclosure to ensure the continuity of fluid circulation by capillarity between its hot end and its cold end.

The invention thus reduces the mass of the heat collection and transport system compared to a conventional heat pipe system. It also has the advantage of enabling better thermal coupling between equipment panels and radiators.

A secondary problem that is solved by the invention is to be more efficient for non-planar dissipative wall equipment.

According to a particular embodiment, the heat transport zone comprises an area of increased deformability in at least one predetermined direction. By deformable zone is meant a zone of low rigidity under the environmental conditions in which the device is supposed to operate.

In this way, it is possible to accommodate deformations occurring between the supports of the ends of the device without practically exerting efforts on these supports. In the particular case of ends arranged one on an equipment panel and the other on a radiator, this deformability of the transport zone makes it possible to accommodate the deformations, for example thermal, without risking breaking the control device. thermal shearing.

In a particular embodiment adapted to the case of two supports of the ends of the device arranged in different planes, the tube comprises several bends arranged in different planes.

The device then comprises two substantially flat flat speakers located in different planes, connected by a tube having two torsion zones, said torsion zones being disposed in at least two different planes, said planes being respectively the planes in which are arranged the flat speakers

In this way, the rigidity of the tube is significantly reduced in two planes, allowing accommodation of a small displacement or angular deformation occurring between these two planes.

In a particular case of implementation, corresponding to the case of a form heat source or well having a plurality of planes, for example at least two planar walls of dissipative equipment, the flat enclosure has a shape comprising at least two substantially flat areas extending in two distinct planes and connected by an edge.

Regardless of these particular embodiments, it is advantageous for the thickness of the flat enclosure to be substantially equal to the diameter of the tube.

In another case of implementation, corresponding to the case of a cylindrical source, part of the outer surface of the flat enclosure has a locally cylindrical shape.

In a particular embodiment, the flat enclosure and at least one tube are made of the same material, for example invar.

Presentation of figures

The characteristics of the invention will be better appreciated thanks to the description which follows, description which sets out the characteristics of the invention through a non-limiting example of application.

• Figures 1a et 1b (déjà citées) : des vues en coupe longitudinale et transversale d'un caloduc selon l'art antérieur,
• Figure 2 : une vue schématique en perspective d'un dispositif de transfert de chaleur selon un mode de réalisation d'un satellite selon l'invention,
• Figures 3b à 3f : des vues de détail du dispositif de la figure 2,
• Figure 4: une vue d'une variante dispositif de transfert de chaleur, adapté au cas d'équipements dissipatifs disposé sur deux plan perpendiculaires,
• Figures 5a à 5c : des vues d'une variante de dispositif de transfert de chaleur, adapté au cas d'un équipement dissipatif de forme sensiblement cylindrique,
• Figure 6 : une vue en perspective d'une autre variante du dispositif,
• Figure 7 : une vue d'une autre variante du dispositif, dans le cas de plusieurs zones d'échange planes,
• Figure 8 : une vue du dispositif de la figure 7, adapté au cas de deux équipements dissipatifs,
• Figure 9 : une vue d'une autre variante du dispositif, utilisant une zone de transport dotée localement d'une semelle de refroidissement,
• Figure 10 : une vue d'une variante du dispositif, comportant une zone d'échange, et plusieurs zones de transport de chaleur,
• Figure 11 : une vue en perspective d'une variante adaptée au cas d'équipements disposés sur deux plans différents,
• Figure 12 : une vue d'une autre variante de dispositif, dans ce même cas.

The description is based on the appended figures which represent:

• Figures 1a and 1b (already mentioned): views in longitudinal and transverse section of a heat pipe according to the prior art,
• Figure 2 : a schematic perspective view of a heat transfer device according to an embodiment of a satellite according to the invention,
• Figures 3b to 3f : detailed views of the device of the figure 2 ,
• Figure 4 : a view of a variant heat transfer device, adapted to the case of dissipative equipment disposed on two perpendicular planes,
• Figures 5a to 5c views of a variant of heat transfer device, adapted to the case of dissipative equipment of substantially cylindrical shape,
• Figure 6 : a perspective view of another variant of the device,
• Figure 7 : a view of another variant of the device, in the case of several planar exchange zones,
• Figure 8 : a view of the device of the figure 7 , adapted to the case of two dissipative equipments,
• Figure 9 : a view of another variant of the device, using a transport zone provided locally with a cooling soleplate,
• Figure 10 : a view of a variant of the device, comprising an exchange zone, and several heat transfer zones,
• Figure 11 : a perspective view of a variant adapted to the case of equipment arranged on two different planes,
• Figure 12 : a view of another variant of device, in this case.

Detailed description of an embodiment of the invention

It is noted first of all that the figures are not to scale.

The invention described here, in an exemplary implementation that is in no way limiting, finds its place in a satellite. This thermal control system is designed and sized according to the equipment onboard the satellite. Its geometry therefore depends on the geometry of the onboard equipment, and their arrangement within said satellite.

In one embodiment given here by way of illustration and in no way limiting, the heat transfer device consists of a thermal chamber containing a two-phase fluid, this chamber having an internal cavity where the fluid can flow freely in the vapor state. and a capillary structure adapted to retain the fluid in the liquid state.

More precisely (see figure 2 ), the device comprises in the first place at least one flat enclosure 1 containing a fluid in the two-phase state and forming a heat exchange zone with a heat source or with a heat sink. An enclosure is considered to be flat, of which in each point one of the dimensions is substantially smaller than the other two dimensions, for example ten times smaller. In the present embodiment, the enclosure is rectangular and flat.

This flat chamber 1 has a capillary structure on all or part of its inner surface at the place where the heat exchange takes place with the heat source or the heat sink. In the example according to the invention, this capillary structure has a wetted surface extended in at least two directions and capable of exchanging a dense heat flow.

Throughout the rest of the description, the so-called "flat enclosure" will be called such a two-phase heat exchange enclosure containing an internal capillary structure facing the heat exchange zone.

In a non-limiting example illustrated on the figure 2 , a flat shape of the flat enclosure 1 is adapted to be in contact with the flat surface of equipment or a radiative panel. The surface of the flat enclosure 1 is, in this example, from a few tens to a few hundred square centimeters of surface, for a thickness of a few tenths of a millimeter to a few millimeters.

The advantage provided by this type of flat enclosure 1 is to be able to have a very wide heat exchange surface with a heat source or a heat sink. Several heat sources or heat sinks can advantageously be mounted in thermal contact with the surface of the enclosure.

The device comprises secondly at least one element of substantially tubular shape, called tube 2, more specifically called "transport tube", its length being significantly larger than the largest dimension of its section.

The tube 2 is secured to the flat chamber 1 at a connection point 3. The tube 2 according to the invention has a capillary structure on its inner wall, such as that of a tubular heat pipe as described above. high and considered known in itself. In the device according to the invention, the function of such a tube is essentially to transport as efficiently as possible the heat collected by the flat enclosure 1.

Throughout the remainder of the description, the term "tube" or "transport tube" will be referred to as such a heat transport tube having a structure internal capillary, this capillary structure for combining the transport of the two-phase fluid both in the form of vapor and in the form of liquid in both directions.

In the case of an application to the cooling of dissipative equipment on board the satellite, the typical length of such a tube 2 may be from a few tens of centimeters to a few meters, and its diameter from one to a few centimeters.

Each transport tube 2 has a significantly smaller section (from 1.5 to several tens of times less) than the largest section of the flat enclosure (the sections being considered in section along the same plane).

The section of the transport tubes 2 is optimized to transport the heat flux exchanged at the level of the flat enclosure 1.

It is important to note that on the figure 2 only a part of the tube is visible because it is presented in section at one end. The tube 2 necessarily extends to at least one other heat exchange zone to which it is connected, this other zone being connected either to a heat sink if the chamber 1 is in heat exchange with a heat source, or to a source of heat if the chamber 1 is in heat exchange with a heat sink. Other figures will show a complete system using the device.

Top and sectional views of this device (see Figures 3b to 3f ) illustrate the arrangement of the different parts of the chamber 1 and the tube 2.

As illustrated by figure 3c , the vapor duct 6 of the tube 2 and the steam duct 5a, 5b, 5c of the flat chamber 1 communicate with each other, so that there is continuity of the flow by inertia of the fluid in vapor form in the two directions between the flat chamber 1 and the tube 2 at their point of connection 3. It is not necessary to have a perfect continuity of the geometry of the steam ducts at the point of connection 3, but it must at least ensure that there is no significant loss of load at this level.

On the other hand, the device is such that there is continuity of capillarity between the capillary structure 7 of the tube 2 and the capillary structure 8 of the flat enclosure 1 at the connection point 3. This capillary continuity must allow the liquid of flow by capillarity in both directions between the flat chamber 1 and the tube 2.

It is recalled that a capillary zone is a geometrically small area where the surface tension effects are predominant over the effects of gravity or inertia. A basic zone of capillarity consists for example of a pore within a porous material, or of a groove in the mass of an inner wall of a tube.

It is not necessary to have a perfect capillary continuity between the capillary structures of the flat enclosure 1 and the tube 2, but at least it must be ensured that there is not a discontinuity of the effect of capillarity at this level. Typically, any discontinuity between the capillary structure of the flat enclosure 1 and that of the tube 2 must not exceed in size the typical dimension of a capillary elementary area, such as a pore and / or a groove, of said capillary structures.

The capillary continuity provided to the connection nodes thus allows the fluid in the liquid phase to flow by capillarity, in an area where the surface tension effects are predominant over gravity or inertia effects. The capillary structure 7 of the tubes 2 consists of grooves ( figure 3d ) and the capillary structure 8 of the flat enclosure 1 consists of a porous structure or a porous material ( figure 3c ), which has a high permeability. In the case where the flat chamber 1 and the tube 2 are made of the same material (aluminum in the most common case), the pore diameter of the porous structure or of the porous material is then chosen such that it is not greater than twice the opening of the grooves of the capillary structure of the tube 2, in order to facilitate the flow of the liquid by capillarity in both directions. This value may change depending on the wettability characteristics of the fluid in the case where different materials are used. The capillary structure of the tube 2 is disposed in capillary continuity with the capillary structure of the flat enclosure 1, also consisting of a porous structure or a porous material, which has a high permeability with a pore diameter that is not greater than the pore diameter of the porous structure or the porous material of the heat pipes. This value can also change depending on the wettability characteristics of the fluid on the different materials used.

In an alternative embodiment, the two-phase capillary exchanger 1 and the transport heat pipe 2 are made in invar, instead of aluminum as used in the prior art. Invar provides the device with greater dimensional stability than aluminum which is advantageous in some applications.

The device which has just been described is able to efficiently collect a dense heat flux emitted by a heat source, and to transport it efficiently towards a remote dissipation zone.

In alternative embodiments, the flat enclosure 1 sees its shape adapted to a non-planar contact surface or in several planes with dissipative equipment.

In this case, the wet surface of the flat enclosure 1 matches the shape of the heat source or heat sink with which it is in contact. If this source or well has a parallelepipedal shape (such as electronic equipment in the case of a heat source), the flat enclosure 1 may have a flat surface conforming to the footprint of the equipment when it is attached to its body. installation plan.

In another case, corresponding to a flat speaker 1 in contact with several planes of the equipment, the flat enclosure 1 consists of two parts 11, 12 planes and perpendicular (see figure 4 ) connected so that there is continuity of their steam ducts and their capillary structures. The connection between the two parts 11, 12 of the planar enclosure and the tube 2 takes place at the intersection angle of the two parts 11, 12 with continuity of steam conduits and capillary structures as previously described. Again, only a portion of the tube 2 is shown, which necessarily extends in a complete thermal control system to another heat exchanger to which it is connected.

If the heat source has a substantially cylindrical shape, such as an electric motor, for example, the flat enclosure 1 has a locally toroidal shape surrounding said source ( Figures 5a to 5c ).

This diversity of form of flat speakers 1 (plane, multi-plane, toric, etc.) can be advantageously manufactured thanks to rapid manufacturing means, in particular based on powders, for example by additive fusion (three-dimensional direct printing). One can then manufacture in a single step all of the flat enclosure 1, namely the walls of the enclosure and the capillary structure. The transport tube 2 may be a "standard" heat pipe tube welded to the part thus manufactured. It can also be manufactured at the same time as the flat speaker thanks to the rapid manufacturing means. The filling of the device is done according to the state of the art of heat pipe using for example a filling tube (sometimes called "queusot") which can be connected to either a flat speaker or a transport tube, the device .

The transport tube 2 of the device can be optimized for carrying out the heat transport function and only this. Such heat pipes are made cheaply.

In an alternative embodiment of the device, a flat heat exchange chamber 1 may be connected to a plurality of transport tubes 2, 2 ', 2 "(two tubes, as in FIGS. figures 7 , 8, 11, 12 , three tubes as on the figures 6 and 10 ) connected to it according to the embodiment previously described.

In another variant ( figure 7 ), the device comprises several flat speakers 1, 1 'interconnected by at least one transport tube 2, the shape of each flat chamber 1 being adapted each to the heat source or heat sink with which it is in contact.

In this same embodiment, at least two flat enclosures 1, 1 ', each flat chamber 1 of the device is in contact with either a heat source 3 or a heat sink 4 ( FIG. figure 8 ). The transport tube 2 connecting the flat speakers 1 to each other is sized to allow efficient heat transport from the heat source 3 to the well In the case where the tube 2 does not itself participate in the heat exchange, it is advantageously dimensioned only for this heat transport function.

The figures 7 and 8 thus present a thermal control system consisting of two flat speakers 1, 1 'connected to a tube 2 according to the embodiment described above. The assembly consisting of two enclosures and the tube forms a sealed cavity in which circulates a two-phase fluid for simultaneously performing heat exchange and efficient heat transport.

In some parts of the device, the collection and evacuation of heat can be carried out with the means of the state of the art, for example by means of a sole 13 placed around the transport tube 2 so this soleplate is in thermal contact with a heat source or heat sink ( figure 9 ). In this case, the tube 2 serves both as a transport tube and as a heat exchanger, which can be advantageous when the heat source (or heat sink) in contact with the sole of the tube 2 is of large size.

The Figures 11 and 12 illustrate other embodiments of the device, wherein the transport tube 2 is curved and connects two heat exchange zones (here two flat speakers 1, 1 ') whose surfaces are located in different planes. In the case of figure 12 , the transport tube 2 has several bends 14, 15, located in different planes, which gives it a significantly increased deformability in at least one direction, in a predetermined area, to accommodate small displacement or angular deformation between the support planes the two-phase capillary exchangers 1, 1 '.

Advantages

• Un premier besoin est le transport d'énergie d'un point a à un point b à l'intérieur du satellite. On comprend que ce besoin conditionne la capacité de transport d'énergie nécessaire pour le caloduc.
• Un second besoin est l'étalement ou la répartition de chaleur sur une surface faisant office de radiateur. Ce besoin conditionne la distance minimale entre deux caloducs sur la surface de radiateur.
• Un troisième besoin est l'échange de chaleur. Dans ce cas, le caloduc est typiquement installé directement sous un équipement pour assurer un bon échange thermique avec celui-ci. Le problème est alors d'assurer le meilleur couplage thermique possible entre le caloduc et l'équipement auquel il est attaché. Ce couplage thermique est alors lui-même fonction de la surface mouillée du caloduc (surface du caloduc en contact avec le liquide).

Le satellite de l'invention répond au mieux à ces différents besoins grâce à la connexion capillaire des surfaces mouillées d'enceintes aux formes adaptées à la fois aux échanges thermiques et au transport de chaleur. Le satellite selon l'invention offre des solutions d'échange thermique et de transport de la chaleur à moindre coût maximisant l'efficacité de l'échange thermique quelle que soit la forme externe de la source ou du puits de chaleur, tout en minimisant la masse et l'encombrement de la solution de transport ainsi que le coût et la complexité du système d'échange thermique et de transport dans son ensemble.Heat pipes meet three types of needs:

• A first need is the transport of energy from a point a to a point b inside the satellite. It is understood that this requirement conditions the energy transport capacity required for the heat pipe.
• A second need is the spreading or the distribution of heat on a surface acting as a radiator. This requirement conditions the minimum distance between two heat pipes on the radiator surface.
• A third need is the exchange of heat. In this case, the heat pipe is typically installed directly under equipment to ensure a good heat exchange with it. The problem is then to ensure the best possible thermal coupling between the heat pipe and the equipment to which it is attached. This thermal coupling is itself a function of the wet surface of the heat pipe (surface of the heat pipe in contact with the liquid).

The satellite of the invention best meets these different needs through the capillary connection of wet surfaces of enclosures to forms adapted to both heat exchange and heat transport. The satellite according to the invention offers heat exchange and heat transport solutions at lower cost maximizing the efficiency of the heat exchange whatever the external form of the source or the heat sink, while minimizing the mass and congestion of the transport solution as well as the cost and complexity of the heat exchange and transport system as a whole.

It is recalled that a heat pipe ("heat pipe" in English, to distinguish from "loop heat pipe", which designates a fluid loop, with completely different behavior) uses the phase change of a fluid to ensure the collection of heat in a warm place, and its transfer as a vapor to a cold place. A tubular heat pipe is conventionally composed of a closed tube in which the liquid and gaseous phases of the same fluid coexist kept under pressure. The heat pipe makes it possible to store the heat by evaporation and to restore it by condensation of the fluid.

As a clarification, it seems necessary to distinguish a heat pipe ("heat pipe" in English) as used in the present device, a fluid loop ("loop heat pipe" in English), with completely different behavior, such as cited in various prior art documents.

A "loop heat pipe" is in the form of a closed-loop circuit in which the fluid circulates in one direction, whereas a heat pipe is not configured in a closed loop. . Indeed, inside its cavity, the liquid and vapor phases coexist and flow in different directions between the two ends of said cavity.

In an example of such a fluid-loop device, described in the document WO 2012/049752 (Itoh, October 2010 ), the liquid and gaseous phases are separated by at least one porous wall.

This difference is major because it leads to a behavior totally different from the system with an increased pumping pressure by the separative porous wall in the case of fluid loops, and operating limits induced by the physical separation of phases that do not exist in the heat pipe system due to the coexistence of the liquid and vapor phases.

Similarly, this prior art WO 2012/049752 the field of fluid loops does not describe a "capillary" structure, according to the meaning generally known to those skilled in the art. The device of this prior document comprises a first pipe 150 carrying only liquid without capillary effect, and a second pipe 155 carrying only a vapor phase.

A document US 2006/0283577 (December 2006 also discloses a fluid loop ( "A loop-type heat exchanger device (10) is disclosed, which includes and evaporator (20), to condense (40), to vapor leads (30) and a liquid conduit (50). . "). This document does not relate to a device comprising a cavity in which the liquid and vapor phases of the same fluid coexist. On the contrary, it is clear in view of the figure 6 (also described in the text in paragraphs [0028] to [0029]) that the tube 30 is adapted to transport only a vapor phase fluid, not a liquid and a vapor phase.

Another previous document relating to fluid loops, US 2009/0114374 (Kyushu University, May 2009), once again describes a device in which the liquid and vapor phases of the same fluid do not coexist in the same transport cavity. This is particularly apparent from the abstract "the liquid state refrigerant is supplied from the liquid supply channel 32, ... and the evaporated refrigerant is discharged from the heat removal use channel 31." Furthermore, the device described in this document does not use a capillary effect for the transport of fluid.

Claims (7)

1. Satellite comprising a heat pipe for the thermal control of electronic equipments, said heat pipe being formed by a closed cavity containing a two-phase fluid, characterized in that the heat pipe comprises:

   - at least one heat exchange zone comprising a flat enclosure (1) configured in the form of a volume of which one dimension is significantly smaller than the other two, typically at least ten times smaller, said flat enclosure (1) having a first capillary structure (8), formed by a porous structure, over all or part of its inner surface, enabling the fluid in its liquid form to wet said first capillary structure (8),

   - at least one heat transport zone configured in the form of at least one tube (2), of circular cross section, having a second capillary structure (7) over all or part of its inner face,

   - the second capillary structure (7) is formed by grooves,

   - said flat enclosure (1) and said at least one tube (2) are connected such that vapour can circulate freely in all of the cavity, and such that a continuity of capillarity is ensured between the porous structure and the grooves such that the liquid can wet the entire capillary structure thus formed.
2. Satellite according to Claim 1, characterized in that, in the case of a plurality of tubes (2) connected to one and the same flat enclosure (1), said tubes (2) have vapour ducts of which the sum of the passage cross sections is substantially equal to the vapour passage cross section of said flat enclosure (1).
3. Satellite according to either of Claims 1 and 2, characterized in that the heat transport zone comprises a zone of increased deformability in at least one predetermined direction.
4. Satellite according to any one of Claims 1 to 3, characterized in that the heat pipe comprises two substantially planar flat enclosures (1, 1') situated in different planes and connected by a tube (2) having two twisting zones (14, 15), said twisting zones (14, 15) being arranged in at least two different planes.
5. Satellite according to any one of Claims 1 to 4, characterized in that the flat enclosure (1) has a shape comprising at least two substantially planar zones (11, 12) extending in two separate planes and connected by an edge.
6. Satellite according to any one of Claims 1 to 5, characterized in that the thickness of the flat enclosure (1) is substantially equal to the diameter of the tube (2).
7. Satellite according to any one of Claims 1 to 6, characterized in that a part of the outer surface of the flat enclosure (1) has a locally cylindrical shape.

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