WO2023066755A1 - Capillary-pumped-type heat pipe with re-entrant grooves, having increased thermal conductivity - Google Patents

Capillary-pumped-type heat pipe with re-entrant grooves, having increased thermal conductivity Download PDF

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Publication number
WO2023066755A1
WO2023066755A1 PCT/EP2022/078386 EP2022078386W WO2023066755A1 WO 2023066755 A1 WO2023066755 A1 WO 2023066755A1 EP 2022078386 W EP2022078386 W EP 2022078386W WO 2023066755 A1 WO2023066755 A1 WO 2023066755A1
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WO
WIPO (PCT)
Prior art keywords
heat pipe
evaporator
condenser
liquid
channel
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Application number
PCT/EP2022/078386
Other languages
French (fr)
Inventor
Mathieu Mariotto
Bénédicte CHAMPEL
Jean-Antoine Gruss
Original Assignee
Commissariat A L'energie Atomique Et Aux Energies Alternatives
Airbus Defence And Space Sas
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Application filed by Commissariat A L'energie Atomique Et Aux Energies Alternatives, Airbus Defence And Space Sas filed Critical Commissariat A L'energie Atomique Et Aux Energies Alternatives
Publication of WO2023066755A1 publication Critical patent/WO2023066755A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/04—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure
    • F28D15/046—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with tubes having a capillary structure characterised by the material or the construction of the capillary structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
    • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
    • F28D15/0233—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes the conduits having a particular shape, e.g. non-circular cross-section, annular

Definitions

  • the present invention relates to a capillary pumped heat pipe with reentrant grooves.
  • the present invention aims to improve the thermal conductivity of such a heat pipe.
  • a heat pipe comprises a hermetically sealed enclosure, a working fluid and a capillary network. During manufacture, all the air present in the heat pipe is evacuated and a quantity of pure liquid is introduced to saturate the capillary network. An equilibrium is then established between the liquid phase and the vapor phase.
  • the liquid Under the effect of a hot source applied in a zone at one of the longitudinal ends, called the evaporator, the liquid vaporizes by inducing a slight overpressure which causes the movement of the vapor towards a zone at the other longitudinal end, called condenser.
  • the condenser At the condenser, the vapor condenses and returns to the liquid phase.
  • the condensed fluid circulates in the capillary network and returns to the evaporator under the effect of capillary forces, when the heat pipe is not subjected to gravity.
  • the return of the liquid fluid from the condenser to the evaporator is obtained by capillary pumping.
  • Slotted heat pipes work on the principle of capillary pumping. They have a tube, in which the inner surface has axial/longitudinal [1] or slightly spiral-shaped grooves. Slotted heat pipes have a vapor core and a capillary network through which the liquid circulates. Due to a variation in curvature of the liquid-vapor interface between the condenser zone and the evaporator zone, a pressure gradient appears in the liquid, which leads to a variation in capillary pressure. The smaller the width of the grooves, the greater the capillary pumping effect.
  • the maximum power that grooved heat pipes can carry is generally fixed by the capillary limit, the driving term of which is the capillary pressure, and the limiting term essentially the loss of liquid pressure in the grooves and, to a lesser extent, the pressure drops of the steam flow.
  • Reentrant groove heat pipes are special examples of grooved heat pipes, in which the grooves have a narrow connecting channel with respect to the rest of the groove, which makes it possible to increase the capillary pumping effect while limiting the losses of charge.
  • These heat pipes are mainly used in the space field, for example for thermal regulation in satellites and/or spacecraft.
  • Another technique uses mechanical machining, with this technique also the depth to width ratio is not substantially greater than 1. In addition, this technique has a relatively high cost price and is not suitable for manufacturing on average and large series.
  • Another technique uses chemical etching. But it also does not make it possible to have a significant depth-to-width ratio.
  • the general object of the invention is then to meet this need at least in part.
  • the invention firstly relates to a heat pipe with reentrant grooves, extending along a first longitudinal direction (X), comprising a sealed enclosure extending between a first longitudinal end, intended to be heated by a hot source to form, within the enclosure, an evaporator and a second longitudinal end intended to be cooled by a cold source to form, within the enclosure, a condenser, the sealed enclosure delimiting a adiabatic zone between the evaporator and the condenser, the enclosure comprising a stack of plates in a second direction (Z) orthogonal to the first direction (X), the stack comprising two closure plates, at least a number of n modules on top of each other with n being an integer >1, each module comprising at least one intermediate plate between the closure plates, the intermediate plate(s) comprising at least a first intermediate plate comprising at least one window whose edges partly delimit a vapor channel extending along the first direction (X) between the evaporator and the condenser, in which the vapor
  • the structures and spacer plates of the n modules define a single vapor channel and on at least one lateral side of the vapor channel, n liquid channels, the walls between liquid channels are of progressively increased thickness in the evaporator, from the adiabatic zone.
  • the walls between liquid channels are gradually increased in thickness in the condenser, from the adiabatic zone.
  • the length, in the third direction Y, of the liquid-vapor connection channels being progressively increased in the evaporator, from the adiabatic zone.
  • the length, in the third direction Y, of the liquid-vapor connection channels being progressively increased in the condenser, from the adiabatic zone.
  • the structures are only on one side of the window delimiting the vapor channel.
  • the structures can be on each of the two lateral sides of the window, facing each other.
  • the transverse section in a plane YZ of the steam channel is constant over the entire length X of the heat pipe.
  • the invention also relates to a system comprising:
  • the heat pipe being arranged so that the heat flow from the hot source (SC) to the evaporator, and the heat extraction at the condenser towards the cold source (SF ) being on at least one side face of the enclosure facing the liquid channels, or on a side face perpendicular thereto.
  • the invention essentially consists in proposing a heat pipe with reentrant grooves, which unlike the heat pipes according to the state of the art with identical internal cross-section over the entire length of the heat pipe, has walls between liquid channels which are thickened in the evaporator, and advantageously in the condenser. Even if this thickening degrades the capillary limit a little, it has the advantage of pushing back the boiling limit and improving the conductance of the heat pipe at the evaporator, and therefore the total conductance, by improving the thermal path between hot and fluid source.
  • the inventors of the present invention started from thermal modeling.
  • the overall thermal resistance of a heat pipe can be evaluated by making an analogy of a network of independent thermal resistances.
  • Such a network is schematized in figure 1 in which a heat flux Q emitted by a hot source SC must be evacuated by a heat pipe to a cold source.
  • the heat pipe can be considered as a set of a number of eleven thermal resistances RI to Rl l in series and/or in parallel as shown in this figure 1.
  • the axial resistances of the outer wall RIO and of the capillary network Rl l along the length of the heat pipe are immense. Consequently, the preferred heat flow path is that passing through the steam circulation section. This path consists of five different resistors, as follows:
  • the limiting thermal resistance is that of the liquid channels (capillary network), respectively at the evaporator and at the condenser (R3, R7).
  • the author of the publication [6] proposed a thermal resistance model with a path through the liquid in the groove in parallel with a conductive path in the tooth and then in the evaporation film.
  • the inventors of the present invention have analyzed that with the production of heat pipes with reentrant grooves according to patent application EP3553445, which consists of stacking then assembling between them punched or machined metal plates to define the different heat pipe channels, they could advantageously thicken the walls between channels at the evaporator and at the condenser to increase the thermal conductivity of a heat pipe.
  • the invention brings many advantages among which we can cite those compared to patent application EP3553445, as follows: increase in the thermal conductance of the heat pipe, increase in the boiling limit of the heat pipe.
  • the three zones of a heat pipe according to the invention do not have the same internal cross section, different heat pipes will have to be made for two applications whose lengths of the three zones differ, this which is not favorable from a production cost point of view.
  • this disadvantage is compensated by better performance.
  • the invention applies to a large number of fields in which a system, in particular an electronic system, must be thermally managed, but in particular for on-board systems in the space field to be thermalized.
  • Figure 1 is a symbolic representation of a network of thermal resistances that are established for a heat pipe.
  • Figure 2 is a schematic side view of an example of a heat pipe with reentrant grooves according to the invention.
  • Figures 2 A and 2B are perspective and cross-sectional views along A-A and B-B, respectively, of the evaporator of a reentrant groove heat pipe according to Figure 2.
  • Figure 2C is a perspective and cross-sectional view along C-C of the adiabatic zone of a heat pipe with reentrant grooves according to Figure 2.
  • Figure 2D is a perspective and cross-sectional view along D-D of the condenser of a heat pipe with reentrant grooves according to Figure 2.
  • Figure 2E is a perspective and cross-sectional view along E-E of the condenser of a heat pipe with reentrant grooves according to Figure 2.
  • FIGs 3A and 3B are perspective and cross-sectional views of the evaporator of a heat pipe with reentrant grooves according to the invention, these figures showing the reduction in the width of the walls separating the liquid channels from the end of the heat pipe to the adiabatic zone, and also the reduction in the length of the connecting channel as well as the increase in the length along the Y axis of the liquid channels.
  • FIG. 4 illustrates in the form of curves the capillary limits obtained for a heat pipe with reentrant grooves respectively according to the invention and according to the state of the art.
  • Figure 5 illustrates, in perspective view and in cross section, another embodiment of heat pipe with reentrant grooves according to the invention, each of the two lateral sides comprising six liquid channels in the condenser and evaporator.
  • FIGS. 2 to 2E one can see an example of heat pipe 1 with capillary pumping with reentrant grooves according to the invention.
  • FIG. 2 the example of heat pipe 1 with capillary pumping extending along a longitudinal axis X is seen from the outside.
  • the heat pipe 1 comprises a sealed enclosure 2 extending along the longitudinal axis X between a first longitudinal end 3 and a second longitudinal end 4.
  • the first end 3 is for example intended to be heated by a hot source SC to form within the enclosure an evaporator ZE.
  • the second longitudinal end 4 is intended to be cooled by a cold source SF to form a condenser Zc within the enclosure.
  • the sealed enclosure 2 internally delimits an adiabatic zone ZA between the evaporator and the condenser.
  • the hot source is for example an electrical or electronic component, a heat storage, an exothermic chemical reactor.
  • the cold source is for example a radiative surface, fins in forced convection, cold plates in single or two-phase flow, cold storage, an endothermal chemical reaction, etc.
  • the sealed enclosure 2 is produced by stacking and assembling end plates and modules of intermediate plates 10 arranged between the end plates, according to a method described in patent application EP3553445.
  • a module comprises at least two spacer plates, the plates of the various intermediate plate modules 10 comprising windows or other structuring, being stacked so as to delimit channels 20, 21, 22 as detailed below.
  • a module can also comprise a single plate machined on its two main faces.
  • the plates 10 are preferably made of aluminum alloy and assembled by vacuum brazing.
  • a preferred embodiment consists in machining cladded plates 10 on their two main faces, then carrying out the assembly of these plates by vacuum eutectic brazing. As a variant, it is possible to perform machining on a single main face of the cladded plates.
  • brazing in a salt bath brazing under inert gas, ultrasonic welding, friction-stir welding (“Friction Stir Welding” in English), gluing, etc.
  • the external dimensions of the heat pipes are between a few centimeters and a few meters.
  • the maximum size of heat pipes is generally limited by the tooling available. Indeed, the assembly of sheets by vacuum brazing requires large vacuum furnaces, a few meters in length.
  • windows are made by punching, cutting, for example by laser or water jet.
  • the stack defining the sealed enclosure 2 is then of rectangular parallelepipedal shape with four longitudinal faces 11, 12, 13, 14, parallel to the plane XY or to the plane XZ, each having a large surface promoting heat exchange with the hot source SC and the cold source SF.
  • the stack of plates 10 with their windows or their structures internally delimits a channel called the vapor channel 20, and as detailed below liquid channels 21.1 to 21.6 and connecting channels 22.
  • the vapor channel 20 of constant rectangular cross-section extends along the longitudinal axis X.
  • the vapor channel 20 serves to circulate the vapor phase from the evaporator ZE to the condenser Zc passing through the adiabatic zone. ZA.
  • a liquid channel 21, 21.1 to 21.6 is connected to the vapor channel 20 by a connecting channel 22 with a section in the XZ plane smaller than that of the liquid channel.
  • Each liquid channel is intended for the circulation of the liquid from the condenser Zc to the evaporator ZE.
  • a connecting channel 22 is therefore an exchange zone between the vapor and the liquid.
  • the liquid channels 21, 21.1 to 21.6 have internal cross-sections that are differentiated according to the different zones of the heat pipe (evaporator ZE, adiabatic zone ZA, condenser Zc).
  • FIGS. 2A to 2E show a heat pipe according to the invention comprising liquid channels only on one longitudinal side of the sealed enclosure 2.
  • Figures 2A and 2B show the evaporator of the heat pipe: it comprises a number of six liquid channels 21.1, 21.2, 21.3, 21.4, 21.5, 21.6 of identical cross section between them at a given coast along the X axis, but which evolves gradually from the first longitudinal end 3 to the adiabatic zone ZA.
  • each of the six liquid channels 21.1 to 21.6 has a cross section in the YZ plane which increases from the first longitudinal end 3 (FIG. 2A) to its limit with the adiabatic zone (FIG. 2B).
  • the thickness of the walls separating the six liquid channels 21.1 to 21.6 decreases from the first longitudinal end 3 (FIG. 2A) to its limit with the adiabatic zone (FIG. 2B).
  • FIG. 2C shows the adiabatic zone of the heat pipe: the liquid channels 21.1 to 21.6 have a cross section in the YZ plane and a thickness between channels, which is constant over the entire length X of the adiabatic zone.
  • Figures 2D and 2E show the condenser of the heat pipe: it comprises a number of six liquid channels 21.1, 21.2, 21.3, 21.4, 21.5 21.6 of identical cross section between them at a given dimension along the X axis, but which can evolve gradually from the adiabatic zone ZA to the second longitudinal end 4.
  • FIGS. 3 A and 3B The thickening of the walls between liquid channels 21.1 to 21.6 in the evaporator ZE is illustrated in detail in FIGS. 3 A and 3B.
  • Figures 3A and 3B further illustrate the variation in the length of the liquid-vapor connection channel, which allows on the one hand a better management of the liquid (longer length allowing to accommodate the recoil of the meniscus at the evaporator , and larger volume to accommodate variations in liquid volume as a function of operating temperature), and secondly to push back the boiling limit, and to a lesser extent to improve thermal resistance.
  • the thickening also has the consequence of reducing the section of the liquid flow in the evaporator (from L2 to L1 in the example shown), and therefore increasing its speed, which increases the pressure drops (negative effect on the capillary limit), but has the advantage of delaying the appearance of bubbles (positive effect on the boiling limit).
  • This thickening can be identical over the entire length, or be gradual.
  • the progressive thickening has the advantage of adjusting the section of the liquid flow to the liquid flow, the latter increasing from the first longitudinal end 3 of the heat pipe to the end of the evaporator ZE.
  • the capillary limit drop is 1% to 3% over the temperature range of the heat pipe, this which is negligible. It is specified that the calculation was made starting from the reduction of section of the liquid channel. The assumption is that the section of the liquid channel at the end of the evaporator, and at the end of the condenser, is 50% of that in the adiabatic zone, and that this reduction in section is progressive. This Reduction may be a combination of wall thickening and bonding zone lengthening.
  • FIG. 5 shows an exemplary variant of a heat pipe according to the invention, according to which the liquid channels 21.1, 21.2, 21.3, 21.4, 21.5, 21.6 are arranged on two opposite longitudinal faces 11, 13 of the heat pipe, i.e. say in front of each other.
  • FIGS. 6, 6A and 6B show an arrangement of liquid channels on two opposite longitudinal faces 11, 13 with the heat source flows coming directly into contact with them at the evaporator and the extraction by the cold source also in contact with them at the condenser;
  • FIGS 7, 7 A and 7B show an arrangement of liquid channels on two opposite longitudinal faces 12, 14 with the heat source flows arriving on the faces 11, 13 orthogonal thereto to the evaporator and the extraction by the cold source also by the faces 11, 13 orthogonal thereto to the condenser;
  • FIGS 8, 8A and 8B show an arrangement of liquid channels on a single longitudinal face 14 with the heat source flow arriving on a single face 11 orthogonal thereto to the evaporator and the extraction by the cold source also by a single face 12 opposite it to the condenser;
  • FIGS 9, 9A and 9B show an arrangement of liquid channels on a single longitudinal face 11 with the heat source flow arriving directly on this face 11 at the evaporator and the extraction by the cold source also by a single face 12 orthogonal thereto to the condenser;
  • FIG. 10A and 10B show an arrangement of liquid channels on two opposite longitudinal faces 11, 13 with the heat source flow coming directly into contact with only one of these faces 11 at the evaporator and the extraction by the cold source also by a single face 12 orthogonal to the condenser;
  • FIGs 11, 11A and 11B show an arrangement of liquid channels on two opposite longitudinal faces 12, 14 with the heat source flow arriving on a single face 11 orthogonal thereto to the evaporator and the extraction by the cold source by one of the two faces 11, 13 orthogonal thereto to the condenser.
  • a heat pipe according to the invention may comprise a greater or lesser number of liquid channels than six per longitudinal face.
  • a heat pipe is filled with a two-phase fluid, it may be a fluid well known to those skilled in the art. This is chosen, for example, according to the operating and storage temperature range of the device, according to the constraints due to the pressure, the flammability, the toxicity of the fluid and the chemical compatibility between the fluid and the material. forming the heat pipe.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)

Abstract

The invention essentially consists of a heat pipe with re-entrant grooves, having thicker walls between liquid channels in the evaporator and, advantageously, in the condenser, unlike in the heat pipes of the prior art which have the same internal cross-section along the entire length of the pipe.

Description

Description Description
Titre : Caloduc de type à pompage capillaire avec rainures réentrantes à conductivité thermique augmentée. Title: Capillary pumped type heat pipe with reentrant grooves with increased thermal conductivity.
Domaine technique Technical area
La présente invention concerne un caloduc à pompage capillaire à rainures réentrantes.The present invention relates to a capillary pumped heat pipe with reentrant grooves.
La présente invention vise à améliorer la conductivité thermique d’un tel caloduc. The present invention aims to improve the thermal conductivity of such a heat pipe.
Technique antérieure Prior technique
Un caloduc comporte une enceinte hermétiquement close, un fluide de travail et un réseau capillaire. Lors de la fabrication, tout l'air présent dans le tube caloduc est évacué et on introduit une quantité de liquide pur permettant de saturer le réseau capillaire. Il y a alors établissement d'un équilibre entre la phase liquide et la phase vapeur. A heat pipe comprises a hermetically sealed enclosure, a working fluid and a capillary network. During manufacture, all the air present in the heat pipe is evacuated and a quantity of pure liquid is introduced to saturate the capillary network. An equilibrium is then established between the liquid phase and the vapor phase.
Sous l'effet d'une source chaude appliquée dans une zone à l'une des extrémités longitudinales, désignée évaporateur, le liquide se vaporise en induisant une légère surpression qui provoque le mouvement de la vapeur vers une zone à l’autre extrémité longitudinale, désignée condenseur. Au condenseur, la vapeur se condense et repasse en phase liquide. Le fluide condensé circule dans le réseau capillaire et revient vers l’ évaporateur sous l'effet de forces capillaires, lorsque le caloduc n’est pas soumis à la gravité. Le retour du fluide liquide du condenseur à F évaporateur est obtenu par pompage capillaire. Under the effect of a hot source applied in a zone at one of the longitudinal ends, called the evaporator, the liquid vaporizes by inducing a slight overpressure which causes the movement of the vapor towards a zone at the other longitudinal end, called condenser. At the condenser, the vapor condenses and returns to the liquid phase. The condensed fluid circulates in the capillary network and returns to the evaporator under the effect of capillary forces, when the heat pipe is not subjected to gravity. The return of the liquid fluid from the condenser to the evaporator is obtained by capillary pumping.
Les caloducs à rainures fonctionnent sur le principe du pompage capillaire. Ils comportent un tube, dans lequel la surface intérieure comporte des rainures axiales/longitudinales [1] ou légèrement en forme de spirale. Les caloducs à rainures comportent un cœur vapeur et un réseau capillaire dans lequel circule le liquide. Du fait d'une variation de courbure de l'interface liquide-vapeur entre la zone condenseur et la zone évaporateur, un gradient de pression apparaît dans le liquide, qui mène à une variation de pression capillaire. Plus la largeur des rainures est petite, plus l'effet de pompage capillaire est important. Slotted heat pipes work on the principle of capillary pumping. They have a tube, in which the inner surface has axial/longitudinal [1] or slightly spiral-shaped grooves. Slotted heat pipes have a vapor core and a capillary network through which the liquid circulates. Due to a variation in curvature of the liquid-vapor interface between the condenser zone and the evaporator zone, a pressure gradient appears in the liquid, which leads to a variation in capillary pressure. The smaller the width of the grooves, the greater the capillary pumping effect.
Par ailleurs, des rainures profondes permettent d'obtenir une section de passage pour le retour liquide grande, et donc de minimiser la perte de pression. La puissance maximale que peuvent transporter des caloducs à rainures est généralement fixée par la limite capillaire dont le terme moteur est la pression capillaire, et le terme limitant essentiellement la perte de pression liquide dans les rainures et, dans une moindre mesure les pertes de charge de l’écoulement vapeur. Furthermore, deep grooves make it possible to obtain a large passage section for the liquid return, and therefore to minimize the pressure loss. The maximum power that grooved heat pipes can carry is generally fixed by the capillary limit, the driving term of which is the capillary pressure, and the limiting term essentially the loss of liquid pressure in the grooves and, to a lesser extent, the pressure drops of the steam flow.
Les caloducs à rainures réentrantes sont des exemples particuliers de caloducs à rainures, dans lesquelles les rainures présentent un canal de liaison étroit par rapport au reste de la rainure, ce qui permet d'augmenter l'effet de pompage capillaire tout en limitant les pertes de charge. Ces caloducs sont utilisés principalement dans le domaine spatial, par exemple pour la régulation thermique dans les satellites et/ou les engins spatiaux. Reentrant groove heat pipes are special examples of grooved heat pipes, in which the grooves have a narrow connecting channel with respect to the rest of the groove, which makes it possible to increase the capillary pumping effect while limiting the losses of charge. These heat pipes are mainly used in the space field, for example for thermal regulation in satellites and/or spacecraft.
Les techniques de réalisation connues des caloducs à rainures, et notamment des caloducs à rainures réentrantes, ne permettent pas d'obtenir des rainures ayant une profondeur sensiblement plus grande que leur largeur. Known techniques for producing heat pipes with grooves, and in particular heat pipes with reentrant grooves, do not make it possible to obtain grooves having a depth substantially greater than their width.
Ces caloducs sont réalisés essentiellement par extrusion. Avec une telle technique, le rapport profondeur sur largeur de rainures rectangulaires est de l'ordre de 1. These heat pipes are produced essentially by extrusion. With such a technique, the depth-to-width ratio of rectangular grooves is of the order of 1.
Dans le cas des rainures réentrantes, les contraintes de fabrication sont encore plus draconiennes, limitant la largeur, la longueur du rétrécissement et la section de la partie réentrante. In the case of reentrant grooves, the manufacturing constraints are even more drastic, limiting the width, the length of the constriction and the section of the reentrant part.
Une autre technique utilise l'usinage mécanique, avec cette technique également le rapport profondeur sur largeur n'est pas sensiblement supérieur à 1. En outre, cette technique a un prix de revient relativement élevé et n'est pas adaptée à la fabrication en moyenne et grande série. Another technique uses mechanical machining, with this technique also the depth to width ratio is not substantially greater than 1. In addition, this technique has a relatively high cost price and is not suitable for manufacturing on average and large series.
Une autre technique utilise la gravure chimique. Mais elle ne permet pas non plus d'avoir un rapport profondeur sur largeur important. Another technique uses chemical etching. But it also does not make it possible to have a significant depth-to-width ratio.
Pour pallier ces inconvénients, la demanderesse a proposé dans la demande de brevet EP3553445A1 un caloduc réalisé par empilement de plaques solidarisées entre elles avec étanchéité, dont les plaques d'extrémité formant des plaques de fermeture et les plaques intercalaires sont structurées, de sorte que leur empilement délimite des rainures réentrantes s'étendant sur toute la longueur du caloduc. Les plaques peuvent être assemblées par différentes techniques de soudure, brasure ou collage. Dans le cas de caloducs rainurés, les axes de recherche identifiés par les inventeurs, pour améliorer la conductivité thermique, se focalisent sur les caractéristiques du fluide de travail, notamment par l’utilisation de nano-fluides avec uniquement avec de l’eau comme fluide de travail: [2] ou par l’utilisation de fluides dits remouillants, c’est-à-dire des fluides dont la tension de surface augmente avec la température : [3] ou auto-remouillants [4]. Les auteurs de la publication [5] ont montré que l’effet principal des nanofluides était en réalité la modification de l’état de surface à l’évaporateur du caloduc. To overcome these drawbacks, the applicant has proposed in patent application EP3553445A1 a heat pipe produced by stacking plates secured together with sealing, the end plates of which forming closure plates and the spacer plates are structured, so that their stack defines reentrant grooves extending over the entire length of the heat pipe. The plates can be assembled by different techniques of welding, brazing or gluing. In the case of grooved heat pipes, the lines of research identified by the inventors, to improve the thermal conductivity, focus on the characteristics of the working fluid, in particular by the use of nano-fluids with only water as fluid. work: [2] or by the use of so-called rewetting fluids, that is to say fluids whose surface tension increases with temperature: [3] or self-rewetting [4]. The authors of the publication [5] showed that the main effect of nanofluids was in fact the modification of the surface state at the heat pipe evaporator.
Il existe un besoin pour améliorer encore les caloducs à rainures, plus particulièrement les caloducs à rainures réentrantes, et ce afin d’en optimiser le fonctionnement, d’améliorer leurs performances et d’étendre leurs domaines de fonctionnement, plus particulièrement d’augmenter leur conductivité thermique. There is a need to further improve grooved heat pipes, more particularly heat pipes with reentrant grooves, in order to optimize their operation, improve their performance and extend their operating ranges, more particularly to increase their thermal conductivity.
Le but général de l'invention est alors de répondre au moins en partie à ce besoin. The general object of the invention is then to meet this need at least in part.
Exposé de l’invention Disclosure of Invention
Pour ce faire, l’invention a tout d’abord pour objet un caloduc à rainures réentrantes, s’étendant le long d’une première direction longitudinale (X), comprenant une enceinte étanche s’étendant entre une première extrémité longitudinale, destinée à être échauffée par une source chaude pour former, au sein de l’enceinte, un évaporateur et une deuxième extrémité longitudinale destinée à être refroidie par une source froide pour former, au sein de l’enceinte, un condenseur, l’enceinte étanche délimitant une zone adiabatique entre l’évaporateur et le condenseur, l’enceinte comprenant un empilement de plaques selon une deuxième direction (Z) orthogonale à la première direction (X), l’empilement comprenant deux plaques de fermeture, au moins un nombre de n modules les uns sur les autres avec n étant un entier >1, chaque module comprenant au moins une plaque intercalaire entre les plaques de fermeture, la ou les plaques intercalaires comprenant au moins une première plaque intercalaire comportant au moins une fenêtre dont les bords délimitent en partie un canal vapeur s’étendant le long de la première direction (X) entre l’évaporateur et le condenseur, dans lequel la vapeur est destinée à circuler, et sur au moins un côté latéral de la fenêtre selon une troisième direction (Y) orthogonale aux première (X) et deuxième (Z) directions, au moins une structuration dont les bords délimitent en partie un canal liquide dans l’évaporateur et le condenseur, au moins la première plaque intercalaire délimitant un canal de liaison reliant le canal vapeur et le canal liquide au moins dans l’évaporateur et le condenseur. To do this, the invention firstly relates to a heat pipe with reentrant grooves, extending along a first longitudinal direction (X), comprising a sealed enclosure extending between a first longitudinal end, intended to be heated by a hot source to form, within the enclosure, an evaporator and a second longitudinal end intended to be cooled by a cold source to form, within the enclosure, a condenser, the sealed enclosure delimiting a adiabatic zone between the evaporator and the condenser, the enclosure comprising a stack of plates in a second direction (Z) orthogonal to the first direction (X), the stack comprising two closure plates, at least a number of n modules on top of each other with n being an integer >1, each module comprising at least one intermediate plate between the closure plates, the intermediate plate(s) comprising at least a first intermediate plate comprising at least one window whose edges partly delimit a vapor channel extending along the first direction (X) between the evaporator and the condenser, in which the vapor is intended to circulate, and on at least one lateral side of the window according to a third orthogonal direction (Y) in the first (X) and second (Z) directions, at least one structuring whose edges partly delimit a liquid channel in the evaporator and the condenser, at least the first intermediate plate delimiting a connecting channel connecting the vapor channel and the liquid channel at least in the evaporator and the condenser.
Selon l’invention, les structurations et plaques intercalaires des n modules définissent un canal vapeur unique et sur au moins un côté latéral du canal vapeur, n canaux liquides, les parois entre canaux liquides sont d’épaisseur progressivement augmentée dans l’évaporateur, depuis la zone adiabatique. According to the invention, the structures and spacer plates of the n modules define a single vapor channel and on at least one lateral side of the vapor channel, n liquid channels, the walls between liquid channels are of progressively increased thickness in the evaporator, from the adiabatic zone.
Selon un mode de réalisation avantageux, les parois entre canaux liquides sont d’épaisseur progressivement augmentée dans le condenseur, depuis la zone adiabatique. According to an advantageous embodiment, the walls between liquid channels are gradually increased in thickness in the condenser, from the adiabatic zone.
Avantageusement, la longueur, selon la troisième direction Y, des canaux de liaison liquide- vapeur étant progressivement augmentée dans l’évaporateur, depuis la zone adiabatique.Advantageously, the length, in the third direction Y, of the liquid-vapor connection channels being progressively increased in the evaporator, from the adiabatic zone.
Avantageusement encore la longueur, selon la troisième direction Y, des canaux de liaison liquide-vapeur étant progressivement augmentée dans le condenseur, depuis la zone adiabatique. Also advantageously the length, in the third direction Y, of the liquid-vapor connection channels being progressively increased in the condenser, from the adiabatic zone.
Selon une variante de réalisation avantageuse, les structurations sont seulement d’un côté latéral de la fenêtre délimitant le canal vapeur. According to an advantageous variant embodiment, the structures are only on one side of the window delimiting the vapor channel.
De manière alternative, les structurations peuvent être sur chacun des deux côtés latéraux de la fenêtre, en regard l’un de l’autre. Alternatively, the structures can be on each of the two lateral sides of the window, facing each other.
Avantageusement, la section transversale dans un plan YZ du canal vapeur, de préférence rectangulaire, est constante sur toute la longueur X du caloduc. Advantageously, the transverse section in a plane YZ of the steam channel, preferably rectangular, is constant over the entire length X of the heat pipe.
L’invention a également pour objet un système comprenant : The invention also relates to a system comprising:
- une source froide (SF) ; - a cold source (SF);
- une source chaude (SC) et - a hot spring (SC) and
- au moins un caloduc à rainures réentrantes tel que décrit précédemment, le caloduc étant agencé de sorte que le flux de chaleur de la source chaude (SC) sur l’évaporateur, et l'extraction de chaleur au condenseur vers la source froide (SF) étant sur au moins une face latérale de l’enceinte en regard des canaux liquides, ou sur une face latérale perpendiculaire à ceux-ci. - at least one heat pipe with reentrant grooves as described above, the heat pipe being arranged so that the heat flow from the hot source (SC) to the evaporator, and the heat extraction at the condenser towards the cold source (SF ) being on at least one side face of the enclosure facing the liquid channels, or on a side face perpendicular thereto.
Ainsi, l’invention consiste essentiellement à proposer un caloduc à rainures réentrantes, qui contrairement aux caloducs selon l’état de l’art à section transversale interne identique sur toute la longueur du caloduc, présente des parois entre canaux liquides qui sont épaissies dans l’évaporateur, et avantageusement dans le condenseur. Même si cet épaississement dégrade un peu la limite capillaire, il a l’avantage de repousser la limite d’ébullition et d’améliorer la conductance du caloduc au niveau de l’évaporateur, et donc la conductance totale, en améliorant le chemin thermique entre source chaude et fluide. Thus, the invention essentially consists in proposing a heat pipe with reentrant grooves, which unlike the heat pipes according to the state of the art with identical internal cross-section over the entire length of the heat pipe, has walls between liquid channels which are thickened in the evaporator, and advantageously in the condenser. Even if this thickening degrades the capillary limit a little, it has the advantage of pushing back the boiling limit and improving the conductance of the heat pipe at the evaporator, and therefore the total conductance, by improving the thermal path between hot and fluid source.
Pour améliorer la conductivité thermique d’un caloduc, les inventeurs de la présente invention sont repartis d’une modélisation thermique. To improve the thermal conductivity of a heat pipe, the inventors of the present invention started from thermal modeling.
De fait, la résistance thermique globale d’un caloduc peut être évaluée en faisant une analogie de réseau de résistances thermiques indépendantes. In fact, the overall thermal resistance of a heat pipe can be evaluated by making an analogy of a network of independent thermal resistances.
Un tel réseau est schématisé en figure 1 dans laquelle un flux de chaleur Q émis par une source chaude SC doit être évacué par un caloduc jusqu’à une source froide. Such a network is schematized in figure 1 in which a heat flux Q emitted by a hot source SC must be evacuated by a heat pipe to a cold source.
D’un point de vue thermique, le caloduc peut être considéré comme un ensemble d’un nombre de onze résistances thermiques RI à Rl l en série et/ou en parallèle comme représenté sur cette figure 1. Les résistances axiales de la paroi extérieure RIO et du réseau capillaire Rl l sur la longueur du caloduc sont immenses. Par conséquent, le chemin du flux thermique privilégié est celui passant par la section de circulation de la vapeur. Ce chemin est constitué de cinq résistances différentes, comme suit : From a thermal point of view, the heat pipe can be considered as a set of a number of eleven thermal resistances RI to Rl l in series and/or in parallel as shown in this figure 1. The axial resistances of the outer wall RIO and of the capillary network Rl l along the length of the heat pipe are immense. Consequently, the preferred heat flow path is that passing through the steam circulation section. This path consists of five different resistors, as follows:
- la résistance entre la source extérieure et la paroi RI, R9 respectivement à l’évaporateur et au condenseur; - the resistance between the external source and the wall RI, R9 respectively at the evaporator and at the condenser;
- la résistance de la paroi extérieure R2, R8 respectivement à l’évaporateur et au condenseur;- the resistance of the outer wall R2, R8 respectively to the evaporator and to the condenser;
- la résistance des canaux liquides (réseau capillaire) R3, R7 respectivement à l’évaporateur et au condenseur ; - the resistance of the liquid channels (capillary network) R3, R7 respectively at the evaporator and at the condenser;
- la résistance de l’interface entre liquide et vapeur R4, R6 respectivement à l’évaporateur et au condenseur et - the resistance of the interface between liquid and vapor R4, R6 respectively at the evaporator and at the condenser and
- la résistance de l’écoulement de vapeur R5. - the resistance of the vapor flow R5.
Sur ce chemin, la résistance thermique limitante est celle des canaux liquides (réseau capillaire), respectivement à l’évaporateur et au condenseur (R3, R7). On this path, the limiting thermal resistance is that of the liquid channels (capillary network), respectively at the evaporator and at the condenser (R3, R7).
Pour l’évaporateur, l’auteur de la publication [6] a proposé un modèle de résistance thermique avec un chemin à travers le liquide dans la rainure en parallèle d’un chemin conductif dans la dent puis dans le film d’évaporation. For the evaporator, the author of the publication [6] proposed a thermal resistance model with a path through the liquid in the groove in parallel with a conductive path in the tooth and then in the evaporation film.
Dans ce modèle très conservatif, la conductivité équivalente du film est donnée par une formule empirique selon l’équation 1 : [Equation 1] In this very conservative model, the equivalent conductivity of the film is given by an empirical formula according to equation 1: [Equation 1]
^^a!" “ 0.185 - c ^^ a! " “ 0.185 - c
Dans un caloduc à parois en aluminium et rempli d’ammoniac en tant que fluide de travail, étant donné l’écart de conductivité thermique entre l’ammoniac liquide (0,4 W/m/K) et l’aluminium (150 W/m/K), le chemin privilégié du flux thermique entre la source chaude et la vapeur va passer par les parois métalliques entre canaux liquides. In an aluminum-walled heat pipe filled with ammonia as the working fluid, given the difference in thermal conductivity between liquid ammonia (0.4 W/m/K) and aluminum (150 W/ m/K), the privileged path of the heat flow between the hot source and the vapor will pass through the metal walls between the liquid channels.
Le même schéma se produit au condenseur, où le chemin privilégié du flux thermique entre la vapeur et la source froide va passer par les parois entre canaux. The same pattern occurs at the condenser, where the privileged path of the thermal flux between the vapor and the cold source will pass through the walls between the channels.
Il ressort donc que, pour augmenter la conductance thermique à l’évaporateur et au condenseur, il est avantageux que les parois entre canaux liquides aient une section la plus élevée possible. It therefore appears that, to increase the thermal conductance at the evaporator and at the condenser, it is advantageous for the walls between the liquid channels to have the highest possible section.
Les inventeurs de la présente invention ont analysé qu’avec la réalisation des caloducs à rainures réentrantes selon la demande de brevet EP3553445, qui consiste à empiler puis assembler entre elles des plaques métalliques poinçonnées ou usinées pour définir les différents canaux de caloduc, ils pouvaient avantageusement épaissir les parois entre canaux à l’évaporateur et au condenseur pour augmenter la conductivité thermique d’un caloduc.The inventors of the present invention have analyzed that with the production of heat pipes with reentrant grooves according to patent application EP3553445, which consists of stacking then assembling between them punched or machined metal plates to define the different heat pipe channels, they could advantageously thicken the walls between channels at the evaporator and at the condenser to increase the thermal conductivity of a heat pipe.
Du fait du mode de réalisation du caloduc selon l’invention, il est possible de limiter l’épaississement des parois inter-canaux aux seules zones de l’évaporateur et du condenseur, qui sont de longueur limitée, et dans lesquelles le débit de fluide n’est pas à son maximum, ce qui permet de diminuer l’impact négatif sur la limite capillaire. Due to the embodiment of the heat pipe according to the invention, it is possible to limit the thickening of the inter-channel walls to the sole zones of the evaporator and of the condenser, which are of limited length, and in which the flow of fluid is not at its maximum, which reduces the negative impact on the capillary limit.
L’invention apporte de nombreux avantages parmi lesquels on peut citer ceux par rapport la demande de brevet EP3553445, comme suit: augmentation de la conductance thermique du caloduc, augmentation de la limite d’ébullition du caloduc. The invention brings many advantages among which we can cite those compared to patent application EP3553445, as follows: increase in the thermal conductance of the heat pipe, increase in the boiling limit of the heat pipe.
Etant donné que les trois zones d’un caloduc selon l’invention (évaporateur, zone adiabatique, condenseur) n’ont pas la même section transversale interne, des caloducs différents devront être réalisés pour deux applications dont les longueurs des trois zones diffèrent, ce qui n’est pas favorable d’un point de vue coût de réalisation. Mais, dans le cas de systèmes embarqués, plus particulièrement dans le domaine spatial, ce désavantage est compensé par de meilleures performances. L’invention s’applique à bon nombre de domaines dans lesquels un système notamment électronique doit être géré thermiquement, mais en particulier pour les systèmes embarqués du domaine spatial à thermaliser. Given that the three zones of a heat pipe according to the invention (evaporator, adiabatic zone, condenser) do not have the same internal cross section, different heat pipes will have to be made for two applications whose lengths of the three zones differ, this which is not favorable from a production cost point of view. However, in the case of on-board systems, more particularly in the space domain, this disadvantage is compensated by better performance. The invention applies to a large number of fields in which a system, in particular an electronic system, must be thermally managed, but in particular for on-board systems in the space field to be thermalized.
D'autres avantages et caractéristiques ressortiront mieux à la lecture de la description détaillée, faite à titre illustratif et non limitatif, en référence aux figures suivantes. Other advantages and characteristics will emerge better on reading the detailed description, given by way of illustration and not limitation, with reference to the following figures.
Brève description des dessins Brief description of the drawings
[Fig 1] la figure 1 est une représentation symbolique d’un réseau de résistances thermiques qui s’établissent pour un caloduc. [Fig 1] Figure 1 is a symbolic representation of a network of thermal resistances that are established for a heat pipe.
[Fig 2] la figure 2 est une vue schématique de côté d’un exemple de caloduc à rainures réentrantes selon l’invention. [Fig 2] Figure 2 is a schematic side view of an example of a heat pipe with reentrant grooves according to the invention.
[Fig 2 A] et [Fig 2B] les figures 2 A et 2B sont des vues en perspective et en coupe transversale respectivement selon A-A et B-B, de l’évaporateur d’un caloduc à rainures réentrantes selon la figure 2. [Fig 2 A] and [Fig 2B] Figures 2 A and 2B are perspective and cross-sectional views along A-A and B-B, respectively, of the evaporator of a reentrant groove heat pipe according to Figure 2.
[Fig 2C] la figure 2C est une vue en perspective et en coupe transversale selon C-C de la zone adiabatique d’un caloduc à rainures réentrantes selon la figure 2. [Fig 2C] Figure 2C is a perspective and cross-sectional view along C-C of the adiabatic zone of a heat pipe with reentrant grooves according to Figure 2.
[Fig 2D] la figure 2D est une vue en perspective et en coupe transversale selon D-D du condenseur d’un caloduc à rainures réentrantes selon la figure 2. [Fig 2D] Figure 2D is a perspective and cross-sectional view along D-D of the condenser of a heat pipe with reentrant grooves according to Figure 2.
[Fig 2E] la figure 2E est une vue en perspective et en coupe transversale selon E-E du condenseur d’un caloduc à rainures réentrantes selon la figure 2. [Fig 2E] Figure 2E is a perspective and cross-sectional view along E-E of the condenser of a heat pipe with reentrant grooves according to Figure 2.
[Fig 3A] et [Fig 3B] les figures 3A et 3B sont des vues en perspective et en coupe transversale de l’évaporateur d’un caloduc à rainures réentrantes selon l’invention, ces figures montrant la diminution de la largeur des parois séparant les canaux liquides depuis l’extrémité du caloduc jusque vers la zone adiabatique, et également la diminution de la longueur du canal de liaison ainsi que l’augmentation de la longueur selon l’axe Y des canaux liquides. [Fig 3A] and [Fig 3B] Figures 3A and 3B are perspective and cross-sectional views of the evaporator of a heat pipe with reentrant grooves according to the invention, these figures showing the reduction in the width of the walls separating the liquid channels from the end of the heat pipe to the adiabatic zone, and also the reduction in the length of the connecting channel as well as the increase in the length along the Y axis of the liquid channels.
[Fig 4] la figure 4 illustre sous forme de courbes les limites capillaires obtenues pour un caloduc à rainures réentrantes respectivement selon l’invention et selon l’état de l’art. [Fig 5] la figure 5 illustre, en vue en perspective et en coupe transversale, un autre mode de réalisation de caloduc à rainures réentrantes selon l’invention dont chacun des deux côtés latéraux comprend six canaux liquides dans les condenseur et évaporateur. [FIG 4] FIG. 4 illustrates in the form of curves the capillary limits obtained for a heat pipe with reentrant grooves respectively according to the invention and according to the state of the art. [Fig 5] Figure 5 illustrates, in perspective view and in cross section, another embodiment of heat pipe with reentrant grooves according to the invention, each of the two lateral sides comprising six liquid channels in the condenser and evaporator.
[Fig 6], [Fig 6A], [Fig 6B], [Fig 7], [Fig 7A], [Fig 7B], [Fig 8], [Fig 8A], [Fig 8B], [Fig 9], [Fig 9A], [Fig 9B], [Fig 10], [Fig 10A], [Fig 10B], [Fig 11], [Fig 11 A], [Fig 11B] les figures 6 à 1 IB illustrent différentes possibilités d’agencement des canaux liquides de l’évaporateur et du condenseur d’un caloduc selon l’invention, relativement aux sources chaude et froide. [Fig 6], [Fig 6A], [Fig 6B], [Fig 7], [Fig 7A], [Fig 7B], [Fig 8], [Fig 8A], [Fig 8B], [Fig 9], [Fig 9A], [Fig 9B], [Fig 10], [Fig 10A], [Fig 10B], [Fig 11], [Fig 11 A], [Fig 11B] figures 6 to 1 IB illustrate different possibilities of arrangement of the liquid channels of the evaporator and of the condenser of a heat pipe according to the invention, relative to the hot and cold sources.
Description détaillée detailed description
La figure 1 a déjà été commentée en préambule. Elle ne sera donc pas détaillée ci-après.Figure 1 has already been commented on in the preamble. It will therefore not be detailed below.
Sur les figures 2 à 2E, on peut voir un exemple de caloduc 1 à pompage capillaire à rainures réentrantes selon l’invention. In FIGS. 2 to 2E, one can see an example of heat pipe 1 with capillary pumping with reentrant grooves according to the invention.
Sur la figure 2, l’exemple de caloduc 1 à pompage capillaire s’étendant selon un axe longitudinal X est vu de l’extérieur. In FIG. 2, the example of heat pipe 1 with capillary pumping extending along a longitudinal axis X is seen from the outside.
Le caloduc 1 comporte une enceinte étanche 2 s’étendant selon l’axe longitudinal X entre une première extrémité longitudinale 3 et une deuxième extrémité longitudinale 4. La première extrémité 3 est par exemple destinée à être à être échauffée par une source chaude SC pour former au sein de l’enceinte un évaporateur ZE. La deuxième extrémité longitudinale 4 est destinée à être refroidie par une source froide SF pour former au sein de l’enceinte un condenseur Zc. The heat pipe 1 comprises a sealed enclosure 2 extending along the longitudinal axis X between a first longitudinal end 3 and a second longitudinal end 4. The first end 3 is for example intended to be heated by a hot source SC to form within the enclosure an evaporator ZE. The second longitudinal end 4 is intended to be cooled by a cold source SF to form a condenser Zc within the enclosure.
L’enceinte étanche 2 délimite intérieurement une zone adiabatique ZA entre l’évaporateur et le condenseur. The sealed enclosure 2 internally delimits an adiabatic zone ZA between the evaporator and the condenser.
La source chaude est par exemple un composant électrique ou électronique, un stockage de chaleur, un réacteur chimique exothermique. La source froide est par exemple une surface radiative, des ailettes en convection forcée, des plaques froides en écoulement mono ou diphasique, un stockage de froid, une réaction chimique endo thermique... The hot source is for example an electrical or electronic component, a heat storage, an exothermic chemical reactor. The cold source is for example a radiative surface, fins in forced convection, cold plates in single or two-phase flow, cold storage, an endothermal chemical reaction, etc.
L’enceinte étanche 2 est réalisée par empilement et assemblage de plaques d’extrémité et de modules de plaques intercalaires 10 agencés entre les plaques d’extrémité, selon un procédé décrit dans la demande de brevet EP3553445. Un module comprend au moins deux plaques intercalaires, les plaques des différents modules de plaques intermédiaires 10 comprenant des fenêtres ou d’autres structurations, étant empilées de sorte à délimiter des canaux 20, 21, 22 comme détaillé par la suite. Un module peut aussi comprendre une unique plaque usinée sur ses deux faces principales.The sealed enclosure 2 is produced by stacking and assembling end plates and modules of intermediate plates 10 arranged between the end plates, according to a method described in patent application EP3553445. A module comprises at least two spacer plates, the plates of the various intermediate plate modules 10 comprising windows or other structuring, being stacked so as to delimit channels 20, 21, 22 as detailed below. A module can also comprise a single plate machined on its two main faces.
La réalisation, l’empilement et l’assemblage des plaques n’est pas détaillé ici, on pourra se reporter à la demande précitée EP3553445. Néanmoins, les plaques 10 sont préférentiellement en alliage d’aluminium et assemblées par brasure sous vide. The production, stacking and assembly of the plates is not detailed here, reference may be made to the aforementioned application EP3553445. Nevertheless, the plates 10 are preferably made of aluminum alloy and assembled by vacuum brazing.
Un mode de réalisation préférentiel consiste à usiner des plaques 10 claddées sur leurs deux faces principales, puis réaliser l’assemblage de ces tôles par brasure eutectique sous vide. A titre de variante, on peut réaliser un usinage sur une seule face principale des plaques claddées. A preferred embodiment consists in machining cladded plates 10 on their two main faces, then carrying out the assembly of these plates by vacuum eutectic brazing. As a variant, it is possible to perform machining on a single main face of the cladded plates.
Pour l’assemblage, différents procédés sont envisageables : brasure au bain de sel, brasure sous gaz inerte, soudage par ultrasons, soudure par friction-malaxage (« Friction Stir Welding » en anglais), collage... For assembly, different processes are possible: brazing in a salt bath, brazing under inert gas, ultrasonic welding, friction-stir welding (“Friction Stir Welding” in English), gluing, etc.
Les dimensions extérieures des caloducs sont comprises entre quelques centimètres et quelques mètres. La taille maximale des caloducs est en général limitée par l’outillage disponible. En effet, l’assemblage des tôles par brasure sous vide requiert des fours sous vide de grande taille, de quelques mètres de longueur. The external dimensions of the heat pipes are between a few centimeters and a few meters. The maximum size of heat pipes is generally limited by the tooling available. Indeed, the assembly of sheets by vacuum brazing requires large vacuum furnaces, a few meters in length.
Pour la découpe et l’usinage des tôles, des machines de grande taille sont également requises. En outre, la tenue mécanique de tôles avec des découpes de faible largeur et de grande longueur est à prendre en compte. For sheet metal cutting and machining, large machines are also required. In addition, the mechanical strength of sheets with cutouts of small width and great length must be taken into account.
Par exemple, des fenêtres sont réalisées par poinçonnage, découpage, par exemple au laser ou au jet d’eau. For example, windows are made by punching, cutting, for example by laser or water jet.
Dans l’exemple illustré, toutes les plaques 10 présentent les mêmes dimensions extérieures, l’empilement définissant l’enceinte étanche 2 est alors de forme parallélépipédique rectangle avec quatre faces longitudinales 11, 12, 13, 14, parallèles au plan XY ou au plan XZ, ayant chacune une grande surface favorisant les échanges de chaleur avec la source chaude SC et la source froide SF. Selon l’invention, l’empilement de plaques 10 avec leurs fenêtres ou leurs structurations délimite intérieurement un canal dit canal vapeur 20, et comme détaillé par la suite des canaux liquides 21.1 à 21.6 et des canaux de liaison 22. In the example illustrated, all the plates 10 have the same external dimensions, the stack defining the sealed enclosure 2 is then of rectangular parallelepipedal shape with four longitudinal faces 11, 12, 13, 14, parallel to the plane XY or to the plane XZ, each having a large surface promoting heat exchange with the hot source SC and the cold source SF. According to the invention, the stack of plates 10 with their windows or their structures internally delimits a channel called the vapor channel 20, and as detailed below liquid channels 21.1 to 21.6 and connecting channels 22.
Plus précisément, le canal vapeur 20 de section transversale rectangulaire constante s’étend le long de l’axe longitudinal X. Le canal vapeur 20 sert à la circulation de la phase vapeur de l’évaporateur ZE au condenseur Zc en passant par la zone adiabatique ZA. More specifically, the vapor channel 20 of constant rectangular cross-section extends along the longitudinal axis X. The vapor channel 20 serves to circulate the vapor phase from the evaporator ZE to the condenser Zc passing through the adiabatic zone. ZA.
Un canal liquide 21, 21.1 à 21.6 est relié au canal vapeur 20 par un canal de liaison 22 de section dans le plan XZ plus faible que celle du canal liquide. Chaque canal liquide est destiné à la circulation du liquide du condenseur Zc à l’évaporateur ZE. A liquid channel 21, 21.1 to 21.6 is connected to the vapor channel 20 by a connecting channel 22 with a section in the XZ plane smaller than that of the liquid channel. Each liquid channel is intended for the circulation of the liquid from the condenser Zc to the evaporator ZE.
Un canal de liaison 22 est donc une zone d’échange entre la vapeur et le liquide. A connecting channel 22 is therefore an exchange zone between the vapor and the liquid.
Plus précisément, selon l’invention, les canaux liquides 21, 21.1 à 21.6 présentent des sections transversales internes différentiées selon les différentes zones du caloduc (évaporateur ZE, zone adiabatique ZA, condenseur Zc). More specifically, according to the invention, the liquid channels 21, 21.1 to 21.6 have internal cross-sections that are differentiated according to the different zones of the heat pipe (evaporator ZE, adiabatic zone ZA, condenser Zc).
Cette différentiation est bien visible en relation avec les figures 2 A à 2E. This differentiation is clearly visible in relation to FIGS. 2A to 2E.
Ces figures 2 A à 2E montrent un caloduc selon l’invention comprenant des canaux liquides uniquement sur un côté longitudinal de l’enceinte étanche 2. These figures 2A to 2E show a heat pipe according to the invention comprising liquid channels only on one longitudinal side of the sealed enclosure 2.
Les figures 2A et 2B montrent l’évaporateur du caloduc : il comprend un nombre de six canaux liquides 21.1, 21.2, 21.3, 21.4, 21.5, 21.6 de section transversale identique entre eux à une côte donnée selon l’axe X, mais qui évolue progressivement depuis la première extrémité longitudinale 3 jusque la zone adiabatique ZA. Figures 2A and 2B show the evaporator of the heat pipe: it comprises a number of six liquid channels 21.1, 21.2, 21.3, 21.4, 21.5, 21.6 of identical cross section between them at a given coast along the X axis, but which evolves gradually from the first longitudinal end 3 to the adiabatic zone ZA.
Plus précisément, chacun des six canaux liquides 21.1 à 21.6 présente une section transversale dans le plan YZ qui augmente depuis la première extrémité longitudinale 3 (figure 2A) jusqu’à sa limite avec la zone adiabatique (figure 2B). Autrement dit, l’épaisseur des parois séparant les six canaux liquides 21.1 à 21.6 diminue depuis la première extrémité longitudinale 3 (figure 2A) jusqu’à sa limite avec la zone adiabatique (figure 2B). More precisely, each of the six liquid channels 21.1 to 21.6 has a cross section in the YZ plane which increases from the first longitudinal end 3 (FIG. 2A) to its limit with the adiabatic zone (FIG. 2B). In other words, the thickness of the walls separating the six liquid channels 21.1 to 21.6 decreases from the first longitudinal end 3 (FIG. 2A) to its limit with the adiabatic zone (FIG. 2B).
La figure 2C montre la zone adiabatique du caloduc : les canaux liquides 21.1 à 21.6 ont une section transversale dans le plan YZ et une épaisseur entre canaux, qui est constante sur toute la longueur X de la zone adiabatique. Les figures 2D et 2E montrent le condenseur du caloduc : il comprend un nombre de six canaux liquides 21.1, 21.2, 21.3, 21.4, 21.5 21.6 de section transversale identique entre eux à une cote donnée selon l’axe X, mais qui peut évoluer progressivement depuis la zone adiabatique ZA jusque la deuxième extrémité longitudinale 4. FIG. 2C shows the adiabatic zone of the heat pipe: the liquid channels 21.1 to 21.6 have a cross section in the YZ plane and a thickness between channels, which is constant over the entire length X of the adiabatic zone. Figures 2D and 2E show the condenser of the heat pipe: it comprises a number of six liquid channels 21.1, 21.2, 21.3, 21.4, 21.5 21.6 of identical cross section between them at a given dimension along the X axis, but which can evolve gradually from the adiabatic zone ZA to the second longitudinal end 4.
L’épaississement des parois entre canaux liquides 21.1 à 21.6 dans l’évaporateur ZE, est illustré de détail en figures 3 A et 3B. The thickening of the walls between liquid channels 21.1 to 21.6 in the evaporator ZE is illustrated in detail in FIGS. 3 A and 3B.
Les figures 3 A et 3B illustrent en outre la variation de la longueur du canal de liaison liquide- vapeur, ce qui permet d’une part une meilleure gestion du liquide (plus grande longueur permettant d’accommoder le recul du ménisque à l’évaporateur, et plus grand volume pour accommoder les variations de volume liquide en fonction de la température d’opération), et d’autre part de repousser la limite d’ébullition, et dans une moindre mesure d’améliorer la résistance thermique. Figures 3A and 3B further illustrate the variation in the length of the liquid-vapor connection channel, which allows on the one hand a better management of the liquid (longer length allowing to accommodate the recoil of the meniscus at the evaporator , and larger volume to accommodate variations in liquid volume as a function of operating temperature), and secondly to push back the boiling limit, and to a lesser extent to improve thermal resistance.
Il permet d’améliorer la conductance du caloduc au niveau de l’évaporateur et, donc la conductance totale, en améliorant le chemin thermique entre source chaude et fluide. Cela permet de repousser l’apparition de la limite d’ébullition. It makes it possible to improve the conductance of the heat pipe at the level of the evaporator and, therefore the total conductance, by improving the thermal path between the hot source and the fluid. This makes it possible to postpone the appearance of the boiling limit.
L’épaississement a en outre pour conséquence de réduire la section de l’écoulement liquide dans l’évaporateur (de L2 à L1 dans l’exemple illustré), et donc augmenter sa vitesse, ce qui augmente les pertes de charge (effet négatif sur la limite capillaire), mais a l’avantage de repousser l’apparition des bulles (effet positif sur la limite d’ébullition). Plusieurs auteurs ont en effet observé que dans des configurations d’ébullition, augmenter la vitesse de l’écoulement permet de repousser le début de la nucléation : voir par exemple [7] et [8].The thickening also has the consequence of reducing the section of the liquid flow in the evaporator (from L2 to L1 in the example shown), and therefore increasing its speed, which increases the pressure drops (negative effect on the capillary limit), but has the advantage of delaying the appearance of bubbles (positive effect on the boiling limit). Several authors have indeed observed that in boiling configurations, increasing the flow velocity makes it possible to postpone the onset of nucleation: see for example [7] and [8].
Cet épaississement peut être identique sur toute la longueur, ou être progressif. L’épaississement progressif a pour intérêt d’ajuster la section de l’écoulement liquide au débit liquide, celui-ci augmentant depuis la première extrémité longitudinale 3 du caloduc jusqu’à la fin de l’évaporateur ZE. This thickening can be identical over the entire length, or be gradual. The progressive thickening has the advantage of adjusting the section of the liquid flow to the liquid flow, the latter increasing from the first longitudinal end 3 of the heat pipe to the end of the evaporator ZE.
Comme montré sur les courbes de la figure 4, pour un caloduc de 1m de longueur efficace, dont 20cm d’évaporateur et 20cm de condenseur, la chute de limite capillaire est de 1% à 3% sur la plage de température du caloduc, ce qui est négligeable. On précise que le calcul a été fait à partir de la réduction de section du canal liquide. L’hypothèse est que la section du canal liquide à l’extrémité de l’évaporateur, et à l’extrémité du condenseur, est de 50% de celle dans la zone adiabatique, et que cette réduction de section est progressive. Cette réduction peut être une combinaison d’épaississement des parois et d’allongement de la zone de liaison. As shown on the curves in Figure 4, for a heat pipe of 1m effective length, including 20cm of evaporator and 20cm of condenser, the capillary limit drop is 1% to 3% over the temperature range of the heat pipe, this which is negligible. It is specified that the calculation was made starting from the reduction of section of the liquid channel. The assumption is that the section of the liquid channel at the end of the evaporator, and at the end of the condenser, is 50% of that in the adiabatic zone, and that this reduction in section is progressive. This Reduction may be a combination of wall thickening and bonding zone lengthening.
Comme illustré sur les figures précédentes, il est avantageux de ne mettre des canaux liquides que sur une seule face longitudinale, par exemple la face 11 d’un caloduc. As illustrated in the previous figures, it is advantageous to put liquid channels on only one longitudinal face, for example the face 11 of a heat pipe.
Cela permet, pour une section de caloduc constante, d’agrandir les canaux liquides 21, et ainsi de réduire les pertes de charge dans ceux-ci. This makes it possible, for a constant heat pipe section, to enlarge the liquid channels 21, and thus to reduce the pressure drops in them.
La figure 5 montre une variante d’exemple de caloduc selon l’invention, selon laquelle les canaux liquides 21.1, 21.2, 21.3, 21.4, 21.5 21.6 sont agencés sur deux faces longitudinales 11, 13 opposées du caloduc, c’est-à-dire en regard l’une de l’autre. FIG. 5 shows an exemplary variant of a heat pipe according to the invention, according to which the liquid channels 21.1, 21.2, 21.3, 21.4, 21.5, 21.6 are arranged on two opposite longitudinal faces 11, 13 of the heat pipe, i.e. say in front of each other.
Différentes configurations de position des canaux liquides dans le caloduc et par rapport aux sources froides SF et chaudes SC peuvent être envisagées dans le cadre de l’invention :Different position configurations of the liquid channels in the heat pipe and in relation to the cold SF and hot SC sources can be envisaged within the framework of the invention:
- les figures 6, 6A et 6B montrent un agencement de canaux liquides sur deux faces longitudinales opposées 11, 13 avec les flux de source de chaleur qui arrivent directement en contact avec celles-ci à l’évaporateur et l’extraction par la source froide également en contact avec celles-ci au condenseur; - Figures 6, 6A and 6B show an arrangement of liquid channels on two opposite longitudinal faces 11, 13 with the heat source flows coming directly into contact with them at the evaporator and the extraction by the cold source also in contact with them at the condenser;
- les figures 7, 7 A et 7B montrent un agencement de canaux liquides sur deux faces longitudinales opposées 12, 14 avec les flux de source de chaleur qui arrivent sur les faces 11, 13 orthogonales à celles-ci à l’évaporateur et l’extraction par la source froide également par les faces 11, 13 orthogonales à celles-ci au condenseur; - Figures 7, 7 A and 7B show an arrangement of liquid channels on two opposite longitudinal faces 12, 14 with the heat source flows arriving on the faces 11, 13 orthogonal thereto to the evaporator and the extraction by the cold source also by the faces 11, 13 orthogonal thereto to the condenser;
- les figures 8, 8 A et 8B montrent un agencement de canaux liquides sur une seule face longitudinale 14 avec le flux de source de chaleur qui arrive sur une seule face 11 orthogonale à celles-ci à l’évaporateur et l’extraction par la source froide également par une seule face 12 en regard de celle-ci au condenseur; - Figures 8, 8A and 8B show an arrangement of liquid channels on a single longitudinal face 14 with the heat source flow arriving on a single face 11 orthogonal thereto to the evaporator and the extraction by the cold source also by a single face 12 opposite it to the condenser;
- les figures 9, 9A et 9B montrent un agencement de canaux liquides sur une seule face longitudinale 11 avec le flux de source de chaleur qui arrive directement sur cette face 11 à l’évaporateur et l’extraction par la source froide également par une seule face 12 orthogonale à celle-ci au condenseur; - Figures 9, 9A and 9B show an arrangement of liquid channels on a single longitudinal face 11 with the heat source flow arriving directly on this face 11 at the evaporator and the extraction by the cold source also by a single face 12 orthogonal thereto to the condenser;
- les figures 10, 10A et 10B montrent un agencement de canaux liquides sur deux faces longitudinales opposées 11, 13 avec le flux de source de chaleur qui arrive directement en contact avec une seule de ces faces 11 à l’évaporateur et l’extraction par la source froide également par une seule face 12 orthogonale au condenseur; - les figures 11, 11A et 11B montrent un agencement de canaux liquides sur deux faces longitudinales opposées 12, 14 avec le flux de source de chaleur qui arrive sur une seule face 11 orthogonale à celles-ci à l’évaporateur et l’extraction par la source froide par une des deux faces 11, 13 orthogonales à celles-ci au condenseur. - Figures 10, 10A and 10B show an arrangement of liquid channels on two opposite longitudinal faces 11, 13 with the heat source flow coming directly into contact with only one of these faces 11 at the evaporator and the extraction by the cold source also by a single face 12 orthogonal to the condenser; - Figures 11, 11A and 11B show an arrangement of liquid channels on two opposite longitudinal faces 12, 14 with the heat source flow arriving on a single face 11 orthogonal thereto to the evaporator and the extraction by the cold source by one of the two faces 11, 13 orthogonal thereto to the condenser.
D’autres avantages et améliorations pourront être apportées sans pour autant sortir du cadre de l’invention. Other advantages and improvements may be made without departing from the scope of the invention.
Par exemple, un caloduc selon l’invention peut comporter un nombre plus, ou moins important de canaux liquides que six par face longitudinale. For example, a heat pipe according to the invention may comprise a greater or lesser number of liquid channels than six per longitudinal face.
L’invention n’est pas limitée aux exemples qui viennent d’être décrits; on peut notamment combiner entre elles des caractéristiques des exemples illustrés au sein de variantes non illustrées. The invention is not limited to the examples which have just been described; it is in particular possible to combine together characteristics of the examples illustrated within variants not illustrated.
Un caloduc est rempli d’un fluide diphasique, il peut s’agir d’un fluide bien connu de l’homme du métier. Celui-ci est choisi par exemple en fonction de la gamme de température de fonctionnement et de stockage du dispositif, en fonction des contraintes dues à la pression, l’inflammabilité, la toxicité du fluide et de la compatibilité chimique entre le fluide et le matériau formant le caloduc. A heat pipe is filled with a two-phase fluid, it may be a fluid well known to those skilled in the art. This is chosen, for example, according to the operating and storage temperature range of the device, according to the constraints due to the pressure, the flammability, the toxicity of the fluid and the chemical compatibility between the fluid and the material. forming the heat pipe.
A titre d’exemple, pour un caloduc réalisé en alliage d’aluminium assemblé par brasure eutectique, on peut utiliser comme fluide l’ammoniac, l’acétone, le méthanol, le n-heptane, le R134a ou autres fluides frigorigènes fluorés. By way of example, for a heat pipe made of aluminum alloy assembled by eutectic brazing, it is possible to use as fluid ammonia, acetone, methanol, n-heptane, R134a or other fluorinated refrigerants.
Liste des références citées List of cited references
[1]: Christine Hoa '.«Thermique des caloducs à rainures axiales : études et réalisations pour des applications spatiales». Université de Poitiers, 2004. [1]: Christine Hoa'."Thermal heat pipes with axial grooves: studies and realizations for space applications". University of Poitiers, 2004.
[2]: R.K. Bumataria, N. K. Chavda and H.Panchal, «Current research aspects in mono and hybrid nanofluid based heat pipe technologies», Heliyon 5 : e01627 (2019). [2]: R.K. Bumataria, N. K. Chavda and H. Panchal, “Current research aspects in mono and hybrid nanofluid based heat pipe technologies”, Heliyon 5: e01627 (2019).
[3]: N. K. Gupta, A. K. Tiwari, S. K. Ghosh, «Heat transfer mechanisms in heat pipes using nanofluids» - A review, Exp. Therm. Fluid Sci. 90 : 84-100 (2018). [3]: N. K. Gupta, A. K. Tiwari, S. K. Ghosh, “Heat transfer mechanisms in heat pipes using nanofluids” - A review, Exp. Therm. Fluid Sci. 90:84-100 (2018).
[4]: Y. Hu, K. Huang and J. Huang: “A review of boiling heat transfer and heat pipes behavior with self-rewetting fluids” , Int. J. Heat Mass Transfer 121 : 107-118 (2018). [4]: Y. Hu, K. Huang and J. Huang: “A review of boiling heat transfer and heat pipes behavior with self-rewetting fluids”, Int. J. Heat Mass Transfer 121: 107-118 (2018).
[5]: Do et Jang : “ Effect of nanofluids on the thermal performance of a flat micro heat pipe with a rectangular grooved wick. ” Int. J. Heat Mass Transfer 53 : 2183-2192 (2010). [5]: Do and Jang: “Effect of nanofluids on the thermal performance of a flat micro heat pipe with a rectangular grooved wick. ” Int. J. Heat Mass Transfer 53: 2183-2192 (2010).
[6]: S. W. Chi, “ Heat Pipe Theory and Practice,” McGraw-Hill, NY, U.S.A., 1976. [6]: S.W. Chi, “Heat Pipe Theory and Practice,” McGraw-Hill, NY, U.S.A., 1976.
[7]: M.C. Vlachou, J.S. Lioumbas, K. David, D. Chasapis, T.D. Karapantsios, “ Effect of channel height and mass flux on highly subcooled horizontal flow boiling”, Exp. Therm. Fluid Sci. 83 : 157-168 (2017). [7]: M.C. Vlachou, J.S. Lioumbas, K. David, D. Chasapis, T.D. Karapantsios, “Effect of channel height and mass flux on highly subcooled horizontal flow boiling”, Exp. Therm. Fluid Sci. 83: 157-168 (2017).
[8]: K.R. Balasubramanian, R.A. Krishnan, S. Suresh, “ Spatial orientation effects on flow boiling performances in open microchannels heat sink configuration under a wide range of mass fluxes”, Exp. Therm. Fluid Sci. 99 : 392-406 (2018). [8]: K.R. Balasubramanian, R.A. Krishnan, S. Suresh, “Spatial orientation effects on flow boiling performances in open microchannels heat sink configuration under a wide range of mass fluxes”, Exp. Therm. Fluid Sci. 99:392-406 (2018).

Claims

Revendications Claims
1. Caloduc à rainures réentrantes (1), s’étendant le long d’une première direction longitudinale (X), comprenant une enceinte étanche (2) s’étendant entre une première extrémité longitudinale (3), destinée à être échauffée par une source chaude SC pour former, au sein de l’enceinte, un évaporateur et une deuxième extrémité longitudinale (4) destinée à être refroidie par une source froide SF pour former, au sein de l’enceinte, un condenseur, l’enceinte étanche délimitant une zone adiabatique entre l’évaporateur et le condenseur, l’enceinte comprenant un empilement de plaques (10) selon une deuxième direction (Z) orthogonale à la première direction (X), l’empilement comprenant deux plaques de fermeture, au moins un nombre de n modules les uns sur les autres avec n étant un entier > 1, chaque module comprenant au moins une plaque intercalaire entre les plaques de fermeture, la ou les plaques intercalaires comprenant au moins une première plaque intercalaire (10) comportant au moins une fenêtre dont les bords délimitent en partie un canal vapeur (20) s’étendant le long de la première direction (X) entre l’évaporateur et le condenseur, dans lequel la vapeur est destinée à circuler, et sur au moins un côté latéral de la fenêtre selon une troisième direction (Y) orthogonale aux première (X) et deuxième (Z) directions, au moins une structuration dont les bords délimitent en partie un canal liquide (21.1 à 21.6) dans l’évaporateur et le condenseur, au moins la première plaque intercalaire délimitant un canal de liaison (22) reliant le canal vapeur et le canal liquide au moins dans l’évaporateur et le condenseur, les structurations et plaques intercalaires des n modules définissant un canal vapeur unique (20) et sur, le au moins un côté latéral du canal vapeur, n canaux liquides (21.1 à 21.6), les parois entre canaux liquides étant d’épaisseur progressivement augmentée dans l’évaporateur, depuis la zone adiabatique. 1. Heat pipe with reentrant grooves (1), extending along a first longitudinal direction (X), comprising a sealed enclosure (2) extending between a first longitudinal end (3), intended to be heated by a hot source SC to form, within the enclosure, an evaporator and a second longitudinal end (4) intended to be cooled by a cold source SF to form, within the enclosure, a condenser, the sealed enclosure delimiting an adiabatic zone between the evaporator and the condenser, the enclosure comprising a stack of plates (10) along a second direction (Z) orthogonal to the first direction (X), the stack comprising two closure plates, at least one number of n modules on top of each other with n being an integer > 1, each module comprising at least one intermediate plate between the closure plates, the intermediate plate or plates comprising at least a first intermediate plate (10) comprising at least one window whose edges partially delimit a vapor channel (20) extending along the first direction (X) between the evaporator and the condenser, in which the vapor is intended to circulate, and on at least one lateral side of the window in a third direction (Y) orthogonal to the first (X) and second (Z) directions, at least one structuring whose edges partly delimit a liquid channel (21.1 to 21.6) in the evaporator and the condenser, at least the first intermediate plate delimiting a connection channel (22) connecting the vapor channel and the liquid channel at least in the evaporator and the condenser, the structures and intermediate plates of the n modules defining a single vapor channel (20) and on, the at least one lateral side of the vapor channel, n liquid channels (21.1 to 21.6), the walls between liquid channels being of progressively increased thickness in the evaporator, from the adiabatic zone.
2. Caloduc à rainures réentrantes selon la revendication 1, les parois entre canaux liquides étant d’épaisseur progressivement augmentée dans le condenseur, depuis la zone adiabatique. 2. Heat pipe with reentrant grooves according to claim 1, the walls between liquid channels being of progressively increased thickness in the condenser, from the adiabatic zone.
3. Caloduc à rainures réentrantes selon la revendication 1 ou 2, la longueur, selon lea troisième direction Y, des canaux de liaison liquide- vapeur étant progressivement augmentée dans l’évaporateur, depuis la zone adiabatique. 3. Heat pipe with reentrant grooves according to claim 1 or 2, the length, according to the third direction Y, of the liquid-vapor connection channels being gradually increased in the evaporator, from the adiabatic zone.
4. Caloduc à rainures réentrantes selon l’une des revendications précédentes, la longueur, selon la troisième direction Y, des canaux de liaison liquide-vapeur étant progressivement augmentée dans le condenseur, depuis la zone adiabatique. 4. Heat pipe with reentrant grooves according to one of the preceding claims, the length, in the third direction Y, of the liquid-vapor connection channels being gradually increased in the condenser, from the adiabatic zone.
5. Caloduc à rainures réentrantes selon l’une des revendications précédentes, les structurations étant seulement d’un côté latéral de la fenêtre délimitant le canal vapeur.5. Heat pipe with reentrant grooves according to one of the preceding claims, the structuring being only on one lateral side of the window delimiting the vapor channel.
6. Caloduc à rainures réentrantes selon l’une des revendications 1 et 2, les structurations étant sur chacun de deux côtés latéraux de la fenêtre, en regard l’un de l’autre. 6. Heat pipe with reentrant grooves according to one of claims 1 and 2, the structures being on each of two lateral sides of the window, opposite one another.
7. Caloduc à rainures réentrantes selon l’une des revendications précédentes, la section transversale dans un plan YZ du canal vapeur, de préférence rectangulaire, étant constante sur toute la longueur X du caloduc. 7. Heat pipe with reentrant grooves according to one of the preceding claims, the cross section in a plane YZ of the steam channel, preferably rectangular, being constant over the entire length X of the heat pipe.
8. Système comprenant : 8. System comprising:
- une source froide (SF) ; - une source chaude (SC) et - a cold source (SF); - a hot spring (SC) and
- au moins un caloduc à rainures réentrantes selon l’une des revendications précédentes, le caloduc étant agencé de sorte que le flux de chaleur de la source chaude (SC) sur l’évaporateur, et l'extraction de chaleur au condenseur vers la source froide (SF) étant sur au moins une face latérale de l’enceinte en regard des canaux liquides, ou sur une face latérale perpendiculaire à ceux-ci. - at least one heat pipe with reentrant grooves according to one of the preceding claims, the heat pipe being arranged so that the heat flow from the hot source (SC) onto the evaporator, and the heat extraction at the condenser towards the source cold (SF) being on at least one side face of the enclosure facing the liquid channels, or on a side face perpendicular thereto.
PCT/EP2022/078386 2021-10-18 2022-10-12 Capillary-pumped-type heat pipe with re-entrant grooves, having increased thermal conductivity WO2023066755A1 (en)

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