WO2010121365A1 - Dispositif de transfert de chaleur à structure de mèche métallique poreuse à cellules ouvertes - Google Patents

Dispositif de transfert de chaleur à structure de mèche métallique poreuse à cellules ouvertes Download PDF

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Publication number
WO2010121365A1
WO2010121365A1 PCT/CA2010/000580 CA2010000580W WO2010121365A1 WO 2010121365 A1 WO2010121365 A1 WO 2010121365A1 CA 2010000580 W CA2010000580 W CA 2010000580W WO 2010121365 A1 WO2010121365 A1 WO 2010121365A1
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WO
WIPO (PCT)
Prior art keywords
heat transfer
transfer device
heat
porous structure
recited
Prior art date
Application number
PCT/CA2010/000580
Other languages
English (en)
Inventor
Dominic Pilon
Alain Harvey
Mario Patry
Original Assignee
Metafoam Technologies Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metafoam Technologies Inc. filed Critical Metafoam Technologies Inc.
Publication of WO2010121365A1 publication Critical patent/WO2010121365A1/fr

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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
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/20—Modifications to facilitate cooling, ventilating, or heating
    • H05K7/2029—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant with phase change in electronic enclosures
    • H05K7/20336—Heat pipes, e.g. wicks or capillary pumps

Definitions

  • the present invention relates to heat transfer devices such as heat pipes, vapour chambers, and the like.
  • heat transfer devices that have been conventionally used for this purpose are the heat pipe, the vapour chamber, and the like. Depending on their construction, these devices are typically capable of transferring relatively large amounts of thermal energy, in a relatively small space, between areas havmg a relatively small temperature difference. They can thus be used in assisting to maintain an electronic component, for example, such as a computer CPU, witlnn a temperature range in which it relatively reliably operate, even within a small tightly enclosed space such as in a laptop computer. For purposes of the present application, all of these devices ⁇ e.g. heat pipes, vapour chambers, etc.) will be referred to as heat pipes.
  • a typical heat pipe has body having an enclosed closed chamber, a hot section and a cold section.
  • the hot section is the portion of the body that receives the heat to be transferred by the device
  • the cold section is the portion of the body that transfers that heat from the device to wherever it is intended to be transferred, e.g. another structure or ambient fluid.
  • a working fluid such as water, is provided in the closed chamber.
  • the hot section of the heat pipe receives thermal energy, that thermal energy vaporizes the working fluid that is in the vicinity of the hot section
  • the working fluid then in a gaseous state, flows within the heat pipe's enclosed chamber to the cold section, where it condenses into liquid form
  • the latent heat of vaporization that is released by the working fluid during the condensation process is transmitted to the cold section, and then from the heat pipe to whatever structure or fluid the cold section is in contact with
  • a wick may be optionally provided between the cold and the hot sections to assist in transporting the condensed working fluid, then m liquid form, back to the hot section of the heat pipe, where it can again be vaporized and restart the heat transfer cycle within the device. (However, a wick is not required in all heat pipe executions, as, for example, gravity may serve this purpose in some heat pipe executions.)
  • a wick may be made from a simple sintered metallic powered structure, which, owing to its porous structure, pulls the liquid working fluid by capillary action towards the hot section.
  • a simple metal power is exactly that, a powder made solely of metal particles that have been sintered to create metallurgical bonds between the particles.
  • an array of fine channels may be machined on the bottom wall of the closed chamber to (in a different way) cause capillary pressure capable of transporting the liquid working back to the hot section. This list of examples is not intended to be exhaustive.
  • the continuous phase change cycle of the working liquid from liquid to vapour and then back to liquid can provide heat pipes with the characteristic capabilities of transferring heat as described above.
  • a number of factors determine the ultimate heat transport capacity. The key factors tend to be (1) the capability of allowing the vaporized liquid to escape from the boiling liquid at the hot section, and (2) the capability of continuously supplying sufficient amounts of working fluid in a liquid state to the hot section to maintain evaporation (as required). If either of these capabilities are hindered, depending on the extent of the hindrance, the heat transfer cycle may stop.
  • the heat pipe has reached the so called critical heat flux value.
  • working fluid in a gaseous state is essentially trapped by pool of working fluid in a liquid state; the heat pipe essentially ceases to function.
  • the hot section can no longer be continuously supplied with sufficient amounts of working fluid in a liquid state, the heat pipe has reached the so called dry out state. In the dry out state, there is no more working fluid in a liquid state at the hot section to be evaporated, and again the heat pipe essentially ceases to function.
  • the invention provides a heat transfer device, comprising a body having an enclosed chamber therein, a hot section for receiving heat to be transferred by the device, the hot section being in thermal communication with the enclosed chamber, and a cold section for disposing of heat to be transferred by the device, the cold section being in thermal communication with the enclosed chamber; a working fluid disposed within the enclosed chamber, the working fluid being vaporizable by heat received through the hot section, the working fluid being condensable by heat disposed of through the cold section, and a wick disposed within the enclosed chamber for transporting the working fluid in a liquid state via capillary action from the cold section towards the hot section, the wick comprising a metallic open cell porous structure.
  • the metallic open cell porous structure is made by a process including
  • the dry flowable power mixture includes between 65 wt.% and 75 wt.% metal particles
  • the dry flowable power mixture includes between 25 wt.% and 35 wt.% binding agent.
  • the dry flowable power mixture may further includes a foaming agent, and when present, the foaming agent is not greater than 5 0 wt%. Prefeiably, when present, the foaming agent is not greater than 0.5 wt. % or is between 1 0 wt.% and 4.0 wt.4%, depending on the application.
  • the metallic particles include at least metal particles selected from the group consisting of copper, titanium and nickel.
  • pressure may be applied to the mixture at least one of before and during the heating thereof in (ii), (in), and (iv).
  • the process may include shaping the mixture.
  • the present invention provides a heat transfer device, comprising a body having an enclosed chamber therein, a hot section for receiving heat to be transferred by the device, the hot section being in thermal communication with the enclosed chamber, and a cold section for disposing of heat to be transferred by the device, the cold section being in thermal communication with the enclosed chamber; a working fluid disposed withm the enclosed chamber, the working fluid being vapo ⁇ zable by heat received through the hot section, the working fluid being condensable by heat disposed of through the cold section; and a wick disposed within the enclosed chamber for transporting the working fluid m a liquid state via capillary action from the cold section towards the hot section, the wick comprising a metallic open cell porous structure having a wicking speed between 0.0005 m/s and 0.1 m/s .
  • the metallic porous structure has a wicking speed between 0.00075m/s and 0.05 m/s. More preferably, the metallic porous structure has a wicking speed between 0 001 m/s and 0 025 m/s Still more preferably, the metallic porous structure has a wicking speed between 0.0015m/s and 0 0125 m/s. Most preferably, the metallic porous structure has a wickmg speed between 0.002m/s and 0.01 m/s.
  • the present invention provides a heat transfer device, comprising a body having an enclosed chamber therein, a hot section for receiving heat to be transferred by the device, the hot section being m thermal communication with the enclosed chamber, and a cold section for disposing of heat to be transferred by the device, the cold section being in thermal communication with the enclosed chamber, a working fluid disposed within the enclosed chamber, the working fluid being vapo ⁇ zable by heat received through the hot section, the working fluid being condensable by heat disposed of through the cold section; and a wick disposed withm the enclosed chamber for transporting the working fluid in a liquid state via capillary action from the cold section towards the hot section, the wick comprising a metallic open cell porous structure having an absorption capacity between 50 kg/m 3 and 600 kg/m 3 .
  • the metallic porous structure has an absorption capacity between 150 kg/m 3 and 400 kg/m 3 Still more preferably, the metallic porous structure has an absorption capacity between 200 kg/m 3 and 350 kg/m 3 Most preferably, the metallic porous structure has an absorption capacity between 250 kg/m 3 and 300 kg/m 3 .
  • the present invention provides, a heat transfer device, comprising a body having an enclosed chamber therein, a hot section for receiving heat to be transferred by the device, the hot section being in thermal communication with the enclosed chamber, and a cold section for disposing of heat to be transferred by the device, the cold section being in thermal communication with the enclosed chamber, a working fluid disposed withm the enclosed chamber, the working fluid being vapo ⁇ zable by heat received through the hot section, the working fluid being condensable by heat disposed of through the cold section; and a wick disposed within the enclosed chamber for transporting the working fluid in a liquid state via capillary action from the cold section towards the hot section, the wick comprising a metallic open cell porous structure having a specific surface area in a range from 10,000 m 2 /m 3 to 100,000 nr/m 3 .
  • the metallic porous structure has a specific surface area in a range from 15,000 m 2 /m 3 to 80,000 ⁇ r/m 3 . More preferably, the metallic porous structure has a specific surface area in a range from about 18,000 m 2 /m 3 to 70,000 irf/m 3 . Still more preferably, the metallic poious structure has a specific surface area in a range from about 20,000 ⁇ r/m 3 to 60,000 m 2 /m 3 . Most preferably, the metallic porous structure has a specific surface area in a range from 20,000 m 2 /m 3 to 50,000 m 2 /m 3 .
  • the present invention provides a heat transfer device, comprising: a body having an enclosed chamber therein, a hot section for receiving heat to be transferred by the device, the hot section being in thermal communication with the enclosed chamber, and a cold section for disposing of heat to be transferred by the device, the cold section being m thermal communication with the enclosed chamber, a working fluid disposed within the enclosed chamber, the working fluid being vapo ⁇ zable by heat received through the hot section, the working fluid being condensable by heat disposed of through the cold section; and a wick disposed within the enclosed chamber for transporting the working fluid in a liquid state via capillary action from the cold section towards the hot section, the wick comprising a metallic open cell porous structure having an a porosity distribution including (i) a first pore group (a) having an average pore size in a range from 200 ⁇ m to 1000 ⁇ m, (b) having a pore size standard deviation in a range from 100 ⁇ m to 500 ⁇ m, and (c) constitu
  • the first pore group has an average pore size in a range from 200 ⁇ m to 750 ⁇ m. More preferably, the first pore group has an average pore size in a range from 200 ⁇ m to 500 ⁇ m.
  • the second pore group has an average pore size in a range from 40 ⁇ m to 90 ⁇ m. More preferably, the second pore group has an average pore size m a range from 40 ⁇ m to 60 ⁇ m.
  • the third pore group has an average pore size in a range from 500 nm to 15 ⁇ m. 250 nm to 20 ⁇ m. 27. More preferably, the third pore group has an average pore size in a range from 500 nm to 10 ⁇ m
  • the present invention provides a heat transfer device, comprising' a body having an enclosed chamber therein, a hot section for receiving heat to be transferred by the device, the hot section being in thermal communication with the enclosed chamber, and a cold section for disposing of heat to be transferred by the device, the cold section being in thermal communication with the enclosed chamber, a working fluid disposed withm the enclosed chamber, the working fluid being vapo ⁇ zable by heat received through the hot section, the working fluid being condensable by heat disposed of through the cold section; and a wick disposed within the enclosed chamber for transporting the working fluid in a liquid state via capillary action from the cold section towards the hot section, the wick comprising a metallic open cell porous structure having an a porosity distribution including (i) a first pore group (a) having an average pore size in a range from 20 ⁇ m to 200 ⁇ m, (b) having a pore size standard deviation in a range from 10 ⁇ m to 100 ⁇ m, and (c) constituting
  • the first pore group has an average pore size in a range from 40 ⁇ m to 150 ⁇ m. More preferably, the first pore group has an average pore size in a range from 60 ⁇ m to 100 ⁇ m.
  • the second pore group as an average pore size in a range from 500 run to 15 ⁇ m. More preferably, the second pore group as an average pore size in a range from 500 run to 10 ⁇ m.
  • all PCR value are normalized by the PCR of a standard sintered copper powder wick.
  • the reference sintered copper powder wick PCR value is of 3 49E-07 m. Higher normalized PCR ratio should lead to better performing wicks.
  • the present invention provides a heat transfer device, comprising a body having an enclosed chamber therein, a hot side for receiving heat to be transferred by the device, the hot side being in thermal communication with the enclosed chamber, and a cold side for disposing of heat to be transferred by the device, the cold side being in thermal communication with the enclosed chamber; a working fluid disposed within the enclosed chamber, the working fluid bemg vaponzable by heat received through the hot side, the working fluid being condensable by heat disposed of through the cold side, and a wick disposed within the enclosed chamber for transporting the working fluid in a liquid state via capillary action from the cold side towards the hot side, the wick comprising a metallic open cell porous structure having a permeability to capillary ratio between 0.5 and 1000.
  • the metallic porous structure has permeability to capillary ratio between 0.5 and 250. More preferably, the metallic porous structure has permeability to capillary ratio between 0.5 and 75
  • the metallic porous structure includes at least one metal selected from the group consisting of copper, titanium and nickel.
  • the body is oriented such that when the heat transfer device is in use the cold section is below the hot section with respect to gravity, such that the working fluid in a liquid state is transportable by the wick against gravity.
  • Embodiments of the present invention each have at least one of the above-mentioned objects and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present invention that have resulted from attempting to attain the above-mentioned objects may not satisfy these objects and/or may satisfy other objects not specifically recited herein.
  • Figure 1 a longitudinal cross-sectional view of heat pipe constructed according to an embodiment of the invention
  • Figure 2 a transverse cross-sectional view of the heat pipe shown in Figure 1;
  • Figure 3 is cross-sectional view of a heat-pipe according to another embodiment of the invention.
  • Figure 4 illustrates a flat sheet of metallic porous material for use in making the wicking structure of a heat pipe
  • Figure 5 shows the flat sheet of the metallic porous material of Figure 4 formed into a tube for insertion into a heat pipe;
  • Figure 6 shows the rolled tube of metallic porous material placed inside a heat pipe
  • Figure 7 shows a flat sheet including several layers for use in making a heal pipe
  • Figure 8 illustrates the tube structure obtained by rolling the flat sheet of Figure 7;
  • Figure 9 is a cross-sectional shape of a heat pipe according to yet another embodiment of the invention.
  • Figure 10 is perspective view of the heat pipe shown m Figure 9, some elements being shown only partially to expose underlying structures;
  • Figure 11 is a perspective view of a metallic porous structure for use in boiling working liquid in a heat pipe
  • Figure 12 is an enlarged cross-sectional view of the metallic porous structure shown in Figure 11, and
  • Figure 13 illustrates in cross-section of a heat pipe according to yet another embodiment of the invention.
  • FIG. 1 is a longitudinal cross-sectional view of a heat pipe, according to a non-limiting example of embodiment of the invention.
  • the heat pipe 10 is used to provide heat transfer from a heat generating component (not shown).
  • a heat generating component is an electronic component such as a Central Processing Unit (CPU) of a computer.
  • CPU Central Processing Unit
  • Heat pipes are effective heat transfer devices since they rely on the vaporization and condensation of a working fluid, as a heat transfer mechanism
  • the heat pipe 10 which in this example is in the form of an elongated cylinder, has an enclosed chamber 12.
  • the enclosed chamber therefore has cylindrical walls closed by end caps 14.
  • Inside the enclosed chamber 12 is provided a wick in the form of tubular lmer 16.
  • the tubular liner 16 is an metallic open cell porous structure that will be described in greater detail later As shown in the drawings, the tubular liner 16 extends almost the full length of the heat pipe. It should be expressly noted that this is merely an example of an embodiment of the inventions and many variations as to the placement, structure, shape and size of the wick are possible.
  • the heat pipe 12 contains a working fluid.
  • the working fluid is capable of absorbing thermal energy by undergoing a phase transition (from liquid to vapor). The fluid then releases that energy to an external medium (through the cylindrical walls). The energy release causes the vapor to condense. This cycle repeats itself as long as there is heat to dissipate.
  • the heat pipe 12 has a hot section (also referred to herein as a hot section) at which the thermal energy is received and a cold section (also referred to herein as a cold section) from which the thermal energy is dissipated.
  • the hot section and the cold section can be located on any area of the heat pipe structure 12 as long as they are sufficiently spaced apart to allow the phase transitions in the working liquid to take place.
  • the hot section could be the end portion 18 while the cold section could be the end portion 20.
  • the hot section 18 will, in use be in thermal contact (and likely direct contact) with the component to be cooled, while the cold section 20 will release heat to the surrounding medium.
  • This surrounding medium may be air, water or any other suitable material that acts as a heat sink
  • the cold section 20 may be provided with any suitable heat dissipation structure such as fins, for instance (not shown m the drawings).
  • the working fluid is in a liquid phase m the area of the hot section 18.
  • the working liquid boils and is converted to vapor
  • This phase change in the working fluid stores a (relatively) significant amount of thermal energy.
  • the working vapor is allowed to flow toward the cold section 20 via the lumen of the tubular liner 16.
  • the condensation reduces the vapor pressure in the cold section 20 and as a result creates a lower pressure m this region, which has the effect of pulling vapor near the hot section 18 toward the cold section 20. Accordingly, the boiling and the condensation of the working fluid creates a pressure gradient in the heat pipe 12 that naturally causes the vapor to flow from the hot section 18 toward the cold section 20.
  • the tubular liner 16 is a porous structure.
  • the porous structure that will be discussed in greater detail later defines a certain void volume within the "solid" area of the tubular liner 16 (the lumen 22 is not considered to be part of the solid area)
  • the void volume is capable of takmg-up the condensed liquid and carrying that liquid toward the hot section 18. This liquid transport is the result of capillary pressure in the porous structure.
  • the void volume or pores in that area are dry Accordingly, they pull by capillarity the liquid that builds up in the porous structure near the cold section 20. Accordingly, the liquid migrates from the cold section 20 to the hot section 18, in a direction opposite the flow of vapor, so as to sustain cycling of the working fluid.
  • the amount and type of working liquid in the heat pipe 12 will vary according to the intended application. Since the heat transfer mechanism is based on phase transition, it is not necessary to form in the heat pipe 12 a pool of liquid that will submerge a portion of the tubular lmer 16. It is usually sufficient to provide enough liquid so as to create within the tubular linei a continuum of liquid that extends from the cold section 20 to the hot section 18. As to the type of working liquid used, it depends on the temperature range within which the heat transfer is to be provided and also the compatibility of the liquid and the materials used to make the heat pipe 12, including the tubular liner 16. In one specific example, the working liquid is water and the enclosed chamber 12 and the tubular lmer 16 aie both made of copper Other possibilities exist. In operating temperatures under water's freezing point, for example, ammonia (NH 3 ) may be used as the working liquid and nickel as the constituting material for the enclosed chamber 12 and the tubular liner 16
  • the tubular liner 16 is bonded to the inner wall of the enclosed chamber 12 in order to provide for good thermal conductivity. Such thermal conductivity is important to allow heat to easily enter the hot section 18 and boil the liquid and also easily egress the cold section 20. Good thermal conductivity is created by forming an intimate physical contact between the tubular liner 16 and the inner wall of the enclosed chamber 12. Examples of bonding techniques which would work well when the tubular liner 16 is made of metal and that would provide an intimate physical contact include sintering or soldering connections between the tubular liner 16 and the enclosed chamber 12.
  • Soldering is a bonding process whereby a filler metal or alloy is heated to or above its melting temperature, which is generally referred to its liquidus temperature and below the melting temperature or solidus temperature of the base material to be joined.
  • the molten filler metal or alloy flows between two or more close-fitting parts of the material to be joined by capillary action.
  • the molten filler metal or alloy wets the base material and interacts with a thin layer of the base material, cooling to form a sealed joint.
  • soldering encompasses brazing techniques which use non-ferrous filler materials that have a relatively high melting point, generally above 450 degrees Celsius.
  • Sintering is a method for making objects, generally from powdered material, by heating the material until its particles adhere to each other. Sintering does not melt the material particles to create the bond between them: the material particles adhere to each other through a bond mainly created by solid- state diffusion. Effective solid-state diffusion occurs between material particles when they are heated, for a certain time, at temperatures slightly under the melting temperature of the material particles
  • the efficiency of the heat pipe 12 is determined largely by the rate at which it can pump heat out of the hot section 18.
  • One way to increase the efficiency of the heat pipe 12, without altering its size, is to design the heat pipe 12 such that the phase transitions occur at a faster rate. In other words, more working fluid is boiled and condensed per unit of time so as to transfer more heat
  • One factor that limits the rate at which working liquid can be boiled is the ability of the tubular lmcr 16 to replenish the hot section 18 with sufficient amounts of liquid.
  • the material used for making the tubular lmer 16 is designed such that its porosity induces liquid to travel relatively quickly such as to be able to feed the hot section 14 adequately.
  • the tubular liner has a wicking speed between 0.0005 m/s and 0.1 m/s, more preferably between 0 00075m/s and 0 05 m/s, even more preferably between 0.001m/s and 0 025 m/s , yet even more preferably between O 0015m/s and 0.0125 m/s and most preferably between 0.002m/s and 0.01 m/s .
  • a test for determining the wicking speed is provided later in this specification
  • the tubular liner has an absorption capacity between 50 kg/m 3 and 600 kg/m 3 , more preferably between 150 kg/m 3 and 400 kg/m 3 , even more preferably between 200 kg/m s and 350 kg/m 3 , and most pieferably between 250 kg/m 3 and 300 kg/m 3 .
  • a test for determining the absorption capacity is provided later m this specification.
  • the tubular liner 16 is made of metallic material or a metallic alloy material
  • metallic in “metallic porous structure”, “metallic porous material” or any other similar expression is meant that the porous structure or material includes at least 50% of metallic component.
  • the metallic component can be a pure metal or an alloy or an amalgamation of pure metal and alloy.
  • the metal or metals are pieferably transition metals (e.g. copper, nickel, iron) as defined by the periodic table of elements).
  • transition metals e.g. copper, nickel, iron
  • a high metal concentration is preferred m heat management applications since metal has a good thermal conductivity, hence it will transmit heat readily between the interior or the heat pipe 12 and the external environment
  • the resulting mate ⁇ al has a porosity distribution which is characterized by at least two pore groups.
  • the metallic porous material has three pore groups, namely a first pore group, a second pore group and a third pore group.
  • the first pore group has an average pore size in the range from about 200 ⁇ m to about lOOO ⁇ m, preferably in the range from about 200 ⁇ m to about 750 ⁇ m and most preferably from about 200 ⁇ m to about 500 ⁇ m. In each case the standard deviation is in the range from about lOO ⁇ m to about 500 ⁇ m.
  • the first pore size group constitutes from about 30% to about 70% of the void volume of the metallic porous structure.
  • the second pore group has an average pore size in the range from about 40 ⁇ m to about 120 ⁇ m, preferably in the range from about 40 ⁇ m to about 90 ⁇ m and most preferably from about 40 ⁇ m to about 60 ⁇ m. In each case the standard deviation is in the range from about 30 ⁇ m to about 80 ⁇ m.
  • the second pore size group constitutes at least 20% of the void volume of the metallic porous structure.
  • the third pore group has an average pore size in the range from about 250 nm to about 20 ⁇ m, preferably in the range from about 500 nm to about 15 ⁇ m and most preferably from about 500 nm to about lO ⁇ m. In each case the standard deviation is in the range from about 200 nm to about lO ⁇ m.
  • the third pore size group constitutes from about 10% to about 40% of the void volume of the metallic porous structure.
  • the first pore group which has the largest pores is the result of the foaming agent used during the manufacturing of the metallic porous structure, as it will be discussed later.
  • the second pore group which contains smaller pores, are created by inter-pore interstices or voids in the structure between large pores that belong to the first group.
  • the pores of the first group communicate between them via inter-pore interstices, which behave from the perspective of interaction between the material and liquid, as smaller pores.
  • the inter-pore interstices can store liquid and also can induce liquid to migrate through the porous structure via capillary action.
  • the third pore group contains the finest pores of the material. Those pores are defined between the individual metal particles that are bonded via sintering. Since the sintering process does not actually melt the metal particles, those particles bond to adjoining particles at the respective physical contact points, leaving some void spaces between them.
  • the metallic porous material has two pore groups, namely a first pore group and a second pore group.
  • the first pore group has an average pore size in the range from about 20 ⁇ m to about 200 ⁇ m, preferably in the range from about 40 ⁇ m to about 150 ⁇ m and most preferably from about 60 ⁇ m to about 100 ⁇ m. In each case the standard deviation is in the range from about 10 ⁇ m to about 100 ⁇ m.
  • the first pore size group constitutes from about 50% to about 80% of the void volume of the metallic porous structure.
  • the second pore group has an average pore size in the range from about 250 nm to about 15 ⁇ m, preferably in the range from about 500 nm to about 15 ⁇ m and most preferably from about 500 nm to about lO ⁇ m. In each case the standard deviation is in the range from about 200 nm to about lO ⁇ m.
  • the second pore size group constitutes from about 20% to about 50% of the void volume of the metallic porous structure.
  • a metallic porous structure in the form of a flat sheet 400 is manufactured according to the method described later
  • the flat sheet 400 has a pair of mam faces 402 and 404, end edges 406 and 408 and section edges 410 and 412
  • the flat sheet 400 is then rolled into a tube, as shown m Figure 5
  • the rolling operation can be performed by using any appropriate method
  • a mandrel can be provided (not shown) shaped as a rod and having a diameter that corresponds to the lumen of the tubular lmer to be formed
  • the flat sheet 400 is then rolled over the mandrel to obtain the tube 414 of Figure 5
  • the rolling operation causes the metallic porous structure to bend permanently and acquire the tubular shape
  • the section edges 410 and 412 are brought in a face-to-face relationship
  • section edges 410 and 412 can be secured to one another by sintering or soldering Note that this operation is not strictly necessary since the tube 414 is housed in an enclosed chamber, as described below
  • the tube 414 forms an insert that is placed in an outer conduit 600, as shown in Figure 6
  • the conduit 600 has walls which m cross-section define a closed figure, namely a circle
  • the tube 414 is simply inserted in the cylindrical conduit 600
  • the conduit 600 is shown as having a significantly larger diameter than the tube 414 This is shown for clarity only
  • the tube 414 is designed to be tight fitting and as such it contacts the internal wall of the cylindrical conduit 600
  • the tube 414 is constructed such as to leave a small gap between the section edges 410 and 412 Also the diameter is selected such as to be slightly larger than the inner diameter of the cylindrical conduit 600 In this fashion, when the tube 414 is to be inserted into the cylindrical conduit 600, it should be resiliency deformed to bring the section edges 410 and 412 closer to one another to allow the tube 414 to fit within the cylindrical conduit 600 Once inserted, the tube 414 is released and the resilience of the material will cause the tube to spring back against the inner walls of the cylindrical conduit 600 In this fashion a tighter fit can be obtained between the cylindrical conduit 600 and the inner tube 414
  • the inner tube 414 can be bonded to the inner wall of the cylindrical conduit 600 by using any appropriate technique such as sintering or soldering
  • the resulting heat pipe structure has a tubular lmer formed by the tube 414
  • the tube 414 is in contact and follows the shape of the conduit 600 wall
  • the insert may shaped in cross-section as a half-circle or as a quarter of a circle, thus establishing contact with the conduit 600 wall over a smaller area
  • conduits having other shapes can be used.
  • the conduit can be rectangular m cross-section and the insert of porous material can be made as a rectangular tube as well to allow a full perimeter contact with the conduit.
  • the insert can be made as a portion of a rectangle in cross-section when such full perimeter contact is not desired or necessary.
  • FIG. 7 illustrates a variant.
  • a flat sheet 700 is provided that is made from metallic porous mate ⁇ al.
  • the flat sheet 700 is similar to the flat sheet 400 described earlier.
  • the flat sheet 700 has a pair of mam faces 702 and 704, end edges 706 and 708 and section edges 710 and 712
  • the flat sheet 700 is laminated with a layer 714 that after a forming operation will constitute the enclosed chamber of the heat pipe.
  • the layer 714 is made of solid copper.
  • the layer 714 has section edges 716 and 718, opposite to one another.
  • the flat sheet 700 and the layer 714 are laminated by using any suitable technique Preferably, sintering or soldering is used to create a physically strong bond and also enhance the thermal conductivity between the two layers
  • the laminate is then rolled into a tube using a mandrel, as discussed above.
  • the resulting tube is shown in Figure 8 and designated by the reference numeral 800.
  • the outer surface of the tube 800 is formed by the layer 714 whose section edges 716 and 718 meet face-to-face along a joint area 802 that extends along the longitudinal axis of the tube 800 lhe inside of the tube is formed by the metallic porous structure whose section edges 710 and 712 also meet at thejoint area 802.
  • a layer of inorganic porous material such as metallic porous material is provided on the outer wall of the enclosed chamber. This is shown in Figures 9 and 10. More specifically, an outer jacket 900 made of metallic porous material is applied on the outer wall of the enclosed chamber 12 In this fashion, the wall of the enclosed chamber is sandwiched between two metallic porous layers.
  • the purpose of the outer porous layer 900 is to enhance the heat transfer to and from the heat pipe
  • the metallic porous layer 900 can have a porosity that is identical to the porosity of the tubular liner 16 or it can be different. It is advantageous to provide a porosity which has a high specific area and at the same time is open enough to allow a cooling medium to readily flow though the outer porous layer 900. This allows increasing the heat transfer between the surrounding medium and the heat pipe.
  • the outer metallic layer 900 should be bonded to the outer wall of the enclosed chamber such as to create a bond allowing a good thermal conductivity. Examples of bondmg methods include sintering or soldering, among others.
  • the sandwich structure can be made in a similar fashion as the rolled structures described earlier. Specifically, the two flat layers of porous materials are bonded to the central non-porous sheet that is also flat. The resulting laminate is rolled and the meeting ends jointed to one another as deemed appropriate
  • FIG. 3 illustrates another embodiment of a heat pipe.
  • the heat pipe 300 functions conceptually in the same fashion as the heat pipe 10, except that it uses a larger amount of working fluid that forms a pool at the bottom of the heat pipe 300 and that is boiled to provide the heat transfer effect.
  • the heat pipe 300 defines an enclosed chamber 302 having a hot section 304 at the bottom and a cold section 306 at the top.
  • the cold section 306 is formed integrally with cooling fins 308 to facilitate the transfer of heat fiom the cold section 306 to the surrounding medium.
  • a cooling aid can also be provided, such a fan to force air to pass through the cooling fins 308 and thus further enhance the heat transfer.
  • the lower part of the enclosed chamber 302 is provided with a metallic porous structure 310 that is in contact with a pool of working liquid.
  • the amount of working liquid present can vary according to the application but in most cases the metallic porous structure will either be entirely submerged or partially submerged such that in use a pool of liquid is always in contact with the metallic porous structure 310
  • the purpose of the metallic porous structure is generally two fold. First it enhances the heat transfer to the liquid body in order to facilitate the boiling process. Second it also acts as a wick to receive and distribute the condensed liquid that returns to the hot section.
  • the metallic porous structure is characterized by a high specific suiface area to increase the contact surface between the metallic porous structure and the body of liquid.
  • the specific surface area is in the range from about 10,000 m 2 /m 3 to about 100,000 m 2 /m ⁇ preferably of about 15,000 m 2 /m 3 to about 80,000 m 2 /m 3 , even more preferably from about 18,000 m 2 /m 3 to about 70,000 m 2 /m 3 , yet even more preferably from about 20,000 m 2 /m 3 to about 60,000 m 2 /m 3 and most preferably from about 20,000 m 2 /m 3 to about 50,000 mVm 3 .
  • the specific surface area is defined as the available contact surface the metallic porous structure with the body of liquid with relationship to the bulk volume of the metallic porous structure.
  • the metallic porous structure has a pore distribution that is characterized by at least two pore groups, namely a first pore group and a second pore group.
  • the first pore group has an average pore size in excess of 20 ⁇ m.
  • the second pore group has an average pore size in the range from about 250 run to about 15 ⁇ m.
  • the second pore group has an average pore size in the range from about 500 run to about 15 ⁇ m, and most preferably an average pore size in the range from about 500 nm to about lO ⁇ m In each case the standard deviation is in the range from about 200nm to about lO ⁇ m
  • the second pore size group constitutes from about 20% to about 50% of the void volume of the metallic porous stractme
  • the first pore group has an average pore size in the range from about 20 ⁇ m to about 200 ⁇ m, preferably in the range from about 40 ⁇ m to about 150 ⁇ m and most preferably in the range from about 60 ⁇ m to about lOO ⁇ m In each case the standard deviation is in the range from about lO ⁇ m to about lOO ⁇ m
  • the first pore size group constitutes from about 50% to about 80% of the total void volume of the metallic porous structure
  • the metallic porous structure has, in addition to the first and second pore groups a third pore group
  • the first pore group has an average pore size in the range from about 40 ⁇ m to about 120 ⁇ m, preferably from about 40 ⁇ m to about 90 ⁇ m and most pieferably from about 40 ⁇ m to about 60 ⁇ m In each case the standard deviation is in the range from about 30 ⁇ m to about 80 ⁇ m
  • the first pore size group constitutes from about 5% to about 30% of the total void volume of the metallic porous structure
  • the third pore group contains the largest pores and it has an average pore size m the range from about 200 ⁇ m to about lOOO ⁇ m, preferably from about 200 ⁇ m to about 750 ⁇ m and most preferably from about 200 ⁇ m to about 500 ⁇ m In each case the standard deviation is m the range from about lOO ⁇ m to about 500 ⁇ m
  • the third pore group constitutes from about 30% to about 80% of the total void volume of the metallic porous structure
  • Figure 1 1 illustrates a possible va ⁇ ant of the metallic porous structure More specifically, the metallic porous structure 1100 has a length dimension a, a width dimension B and a thickness dimension C In this case the thickness C is significantly less than anyone of the length and width dimensions A and B Note that since the metallic porous structure 1100 is shaped as a disk, the length dimension A is equal to the width dimension B Also note that the disk shape is merely exemplary and many other shapes are possible without departing from the spint of this invention
  • the metallic porous structure 1100 has a pair of mam faces 1102 that are opposite one another and a narrow section surface 1106
  • the mam face 1102 is bonded to a substrate 1108, which in this example is made of copper
  • the purpose of the substrate is to provide a support for the metallic porous structure and allow the metallic porous structure to be handled during the manufactu ⁇ ng of the heat pipe, without breakage Copper, or another metals in general would be the material of choice for manufacturing the substrate 1108 since it provides good thermal conductivity
  • the metallic porous structure 1100 is bonded to the top surface of the substrate 1108 via any suitable technique that would provide good thermal conductivity Examples include sintering and soldering
  • An enlarged cross-sectional view of the metallic porous structure and the underlying substrate 1108 is shown in Figure 12.
  • the metallic porous structure has a plurality of projections 1200 that extend upwardly from a base layer 1204
  • the projections 1200 and the base layer 1204 are integrally formed.
  • the projections 1200 are spaced apart and define between them valleys 1202.
  • the projections have a density in the range of 9 to about 10,000 per square inch.
  • the projection density is in the range of about 25 to about 2,500 per square inch.
  • the projection density is in the range of about 25 to about 1000 per square inch
  • the projections may or may not be distnaded uniformly on the top surface 1102.
  • the method for measuring the projection density is generally a two step approach. The first is to measure the surface area of the top surface 1102. This is done by using any standard measurement techniques. The second is to count the number of projections 1200 that are fo ⁇ ned on the top surface 1102 Finally, the count is divided by the surface area m square inches to determine the number of projections 1200 m a single square inch.
  • an alternative method is to count the number of projections 1200 formed within an area of one square inch, instead of counting the total number of projections 1200 on the top surface 1102.
  • the average projection height is in the range of about 250 ⁇ m to about 10 mm, preferably from about 500 ⁇ m to about 5 mm and most preferably from about 750 ⁇ m to about 3 mm.
  • the method for assessing the average height is to first count the number of projections 1200 on the top surface 1102 and then measuie the height of each projection 1200. All the height values are summed and the result is divided by the total number of projections 1200. Note when the projections 1200 are all of the same height, then it suffices to measure the height of a single projection 1200 in order to determine the average projection height.
  • the height of a projection 1200 is the height as measured from the base of the projection up to its tip. This is dimension Z shown in Figure 12. In other words, the projection height does not include the thickness of the base layer 1204.
  • the average thickness of the base layer is in the range from about 50 ⁇ m to about 2 mm, preferably from about 50 ⁇ m to about 1 mm and most preferably from about lOO ⁇ m to about 1 mm.
  • the average thickness is determined by measuring the dimension X, as shown in Figure 12, associated with each projection 1200. summing up the results and dividing by the number of projections 1200. If the thickness is constant across the metallic porous structure then a single measurement anywhere will suffice to determine the average thickness
  • the projections 1200 are formed on the top surface 1102 by an embossing process.
  • the process starts by providing a metallic porous blank which has two opposite mam faces and a constant thickness. In other words, the thickness dimension measured between the two main faces is the same across the blank.
  • the porous metallic blank is then embossed by using a die (not shown in the drawings)
  • the die has a relief surface that is the exact opposite of the projections and valleys profile desired to be obtained. In other words, for each valley 1202 and projection 1200 to be formed, a corresponding projection and valley are provided on the die.
  • the die is then pressed against one of the mam surfaces of the porous metallic blank in order to emboss the porous metallic blank and thus transfer over the surface the die relief
  • the embossing operation alters somewhat the pore distribution profile of the metallic porous structure. More specifically, the localized compression of the structure that creates valleys has the effect of partially crushing the pores in the material in the areas at which that compression is applied.
  • the pores that are found in the regions of the base layer 1204 between two adjacent projections 1200, which corresponds to the bases of the valleys 1202, are reduced m size.
  • the pore distribution profile that manifests smaller pores at the valley bottoms assists the liquid transport from the projections 1200 to the valley bottoms.
  • the smaller pores in the areas 1206, by virtue of their increased capillary effect then to pull the liquid from the remainder of the metallic porous structure 1100 precisely in the regions where the boiling occurs.
  • the pore distribution profile is such as to modulate the capillary attraction exerted on the liquid by pulling the liquid in the areas from which the liquid is being dissipated by evaporation.
  • FIG. 13 shows another va ⁇ ant of the heat pipe.
  • the heat pipe 1300 is generally similar to the heat pipe 300 discussed above with the difference that the metallic porous structure 1302 is located vertically.
  • This vertical structure can be used for cooling an electronic component that is vertical instead of being installed horizontally.
  • the electronic component such as a CPU 1304 is shown in dotted lines.
  • Metallic porous structures according to the examples described earlier are produced by a method which involves dry-mixing metallic particles, binding agent and optionally a foaming agent, removing the binding agent and then sintering the inorganic particles.
  • the metallic porous material according to the invention can be produced from a dry flowable powder mixture comprising a base material and a binding agent, all provided in predetermined amounts.
  • the base material includes metallic particles having a first melting temperature
  • the binding agent is preferably, but not exclusively, an organic binder, the binder having a decomposition temperature lower than the first melting temperature and having clean burn out characteristics.
  • the inorganic particles comprise metallic particles and/or metallic alloy particles.
  • the metal or metals are preferably transition metals (e.g. copper, nickel, iron) as defined by the periodic table of elements.
  • the inorganic particles will have a first melting temperature
  • the inorganic particle content may vary from about 50 to about 80 wt % of the total weight of the mixture, and preferably from about 65 to about 75 wt %.
  • the binder used in the mixture is preferably an organic binder provided in a dry flowable powdered form and with clean burn out characteristics.
  • the binder can be a thermoplastic polymer, a thermoset resin and/or a combination thereof.
  • the binder can also be an inorganic, a synthetic binder or a mixture of organic and/or inorganic and/or synthetic binders.
  • the binder may be provided in solid form (preferably powder particles), in semi-solid form, in liquid form, in gel form or in semi-liquid form.
  • the binder has a decomposition temperature lower than the first melting temperature of the inorganic particles in order to prevent premature melting of the inorganic particles during the decomposition step.
  • the binder content in the mixture may vary from about 20 to about 50 wt % of the total weight of the mixture and preferably from about 25 to about 35 wt %.
  • the binder should not leave decomposition products that may negatively affect the final properties of the porous structure. However, some residues can be accepted if they have no impact on the final product or if they improve some of its properties.
  • the mixture may comprise a foaming agent
  • the foaming agent content is not greater than 5.0 wt%. It is preferably between 0.0 wt.% to 0.5 wt.% or between 1.0 wt.% to 4.0 wt.% depending on the application.
  • the choice of the foaming agent is such that gaseous species will be released in the temperature range where the binder is liquid or melted. Ideally, it must not leave decomposition products that may negatively affect the final properties of the foamed structure. However, some residues can be accepted if they have no impact on the final product or improve some of its properties.
  • the mixture may comprise a cross-linking agent that may induce faster curing of the binder during or after the curing step and, by the way, improve the mechanical strength of the cured structure before the decomposition of the binder.
  • the mixture may also comprise other additives such as a lubricant to ease shaping, molding or demolding or flowing agents to improve the flowability of the powder when all the constituents are in powdered form.
  • the organic binder can be blended with the other constituent using various techniques such as but not limited to mixing, milling, mixing the binder in. suspension or in solution in a liquid, blending the binder in molten, liquid, gel or semi-liquid form with the inorganic particles and the other additives Whichever mixing technique is used, the resulting product should be a curable mixture.
  • spacing agents may be added to the mixture for providing additional poiosity and to improve pore connectivity.
  • the spacing agents arc removed after curing to leave voids in the structure after decomposition of the binder or after sintering.
  • the spacing agent can be removed by thermal decomposition after curing or by leaching after curing, decomposition of the binder or sintering
  • the spacing agent can be particles or a scaffold When particles are used, they are admixed with the rest of the mixture.
  • the spacing agent can be polymeric particles admixed with the mixture. In this case, the spacing agent concentration can vary from about 5 to 50 wt %, but preferably between 10 and 30 wt %.
  • the scaffold When a scaffold is used, its porous structure is filled with the mixture used to produce the porous material
  • the scaffold can be, for example and in no limiting fashion, a porous structure, like a polymeric foam, that can be filled with the mixture and removed by thermal decomposition or by leaching.
  • additional binder in amount varying between 0.05 wt % to 5 wt %, but preferably between 0.05 wt % to 1 wt %, in the mixture.
  • This additional binder may be generally used to glue different constituents of the mixture together in such a way that the final product is less prone to segregation and/or dusting.
  • This additional binder can also be used to improve the flowability of the mixture should all the constituents be provided in powdered form.
  • the additional binder may be added at different steps of the mixing procedure, either before mixing the inorganic particles with the binder, after the binder addition, after the lubricant addition, after the flowing agent addition or after the addition of any combination of those constituents. Whichever mixing technique is used, the resulting product should be a curable mixture
  • the resulting mixture may be shaped using methods such as molding, deposition, lamination or extrusion.
  • the product is then heated at a moderate temperature to melt the binder, if the latter is not already in liquid, gel or semi-liquid form, and to initiate the curing of the mixture.
  • pressure may be applied to the mixture before or during heating the mixture
  • the resulting open cell porous material porosity and structure will depend on the particle size, shape, density and content of the inorganic particles; the content and viscosity of the binder, as well as the processing conditions.
  • Matenals can be cured in a mold to provide thiee-dimensional porous stnictuies.
  • the mixture can be cured on or in a substrate to produce a coating or to produce composite structures. Curing can be done for example on a plate, on a rod, in or outside a tube or cylinder, in or on other porous structure (mesh, beads, foam for example) or any other substrate.
  • the material can be machined after curing, decomposition of the binder or sintering.
  • Functionally graded materials can be produced using mixtures with variable composition.
  • Graded layered structures can be produced for example by deposing layers of mixtures with different composition
  • Functionally graded materials can also be produced by controlling the thermal gradient during curing in order to control material curing and pore size distribution.
  • the mechanical strength of the cured structure may be further increased, before decomposition of the binder and sintering, by using externally assisted cross-linking techniques such as irradiation or light exposure.
  • the cured mixture is treated at higher temperature to decompose the binder.
  • the atmosphere (with or without the presence of oxygen), duration and temperature of the thermal treatment should preferably allow a clean decomposition of the binder.
  • Binder decomposition should preferably not deteriorate the three-dimensional structure of the cured mixture. If gas pressure generated during binder decomposition is too important, cracking may occur in the still unsmtered structure. Oxidizing or reducing conditions durmg the thermal treatments may be chosen to optimize binder decomposition.
  • the cured mixture is composed of open cell metal, and/or metal alloy, and/or ceramic material particles
  • Sintering is done after the decomposition of the binder to create bonds between the inorganic particles of the cured mixture.
  • Sintering conditions temperature, time and atmosphere
  • conditions should be such that the inorganic particles do not melt to create the bond between them: conditions should be such that the material particles adhere to each other through a bond mainly created by solid-state diffusion to form a strong metallurgical joint between them.
  • Effective solid-state diffusion occurs between material particles when they are heated, for a certain time, at temperatures slightly under the melting temperature of the material particles.
  • Sintering is generally done in reducing atmosphere for metal particles to avoid the formation of surface oxides on the foam.
  • Mechanical strength may be adjusted for the application.
  • the choice, size, nature and/or physical state of the inorganic particles and of the binder content will have a substantial influence of the physical properties (e.g. mechanical strength) of the produced open cell porous material.
  • the internal surface of the foam can be modified for example by heat treatment, chemical treatment or deposition of coatings using various state of the art deposition techniques.
  • the external surfaces of the foam can be modified for example by a stamping, etching, embossing, or grooving technique and by state of the art surface coating techniques.
  • the foams can be integrated in other products and/or to other structures using different state of the art techniques such as diffusion bonding, press fitting, welding, brazing, sintering or gluing. The invention is not so limited.
  • Example 1 produces a metallic foam that has a porosity distribution characterized by two pore groups, while example 2 produces a porosity distribution characterized by three pore groups.
  • a metallic porous structure with copper (Cu) as the base material, was produced with the formulation presented in Table 1.
  • the different constituents were dry-mixed together until the mixture became homogeneous. After mixing, the mixture was poured into a mould and cured at 110 0 C in air for 2 hours. After curing, the material was submitted to the decomposition of the binder in a furnace at 65O 0 C for 4 hours in a dry air stream. Finally, the specimens were sintered in an Ar-25%H 2 atmosphere for 2 hour at 1000 0 C.
  • the Reference Sample is then deposited in a large reservoir filled with the wickmg fluid so that one of its main faces (disc shape surface) is in full contact with the bottom of the reservoir.
  • the Reference sample is not supported in any way by an external apparatus; it is directly deposited inside the reservoir
  • the lateral dimensions of the reservoir are such that there is a 1 mm thick layer of wicking liquid inside the reservoir, with the total volume of wicking fluid inside the reservoir being sufficiently large so that the 1 mm thickness stays relatively constant throughout the wicking test.
  • one end of the Reference Sample is immersed in 1 mm of fluid.
  • the Reference Sample is then quickly removed and placed on a nonabsorbent surface to be weighted to measure the fluid saturated weight of the Reference Sample.
  • the difference in weight between the fluid saturated weight and the dry weight of the Reference Sample is divided by the computed volume of the Reference Sample. This ratio is used as a measure of the absorbent capacity of The Reference Sample.
  • the absorbent capacity is expressed as weight of the test liquid (kg) per volume (m 3 ).

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Abstract

L'invention concerne un dispositif de transfert de chaleur, comprenant une mèche disposée à l'intérieur d'une chambre fermée destinée à transporter un fluide de travail à l'état liquide, par action capillaire, d'une partie froide vers une partie chaude. La mèche comprend une structure métallique poreuse à cellules ouvertes produite au moyen d'un processus consistant à : (i) utiliser un mélange de poudre fluide sèche constitué (a) de 50 à 80% en poids de particules métalliques présentant une première température de fusion, (b) de 20 à 50% en poids d'un agent liant présentant une température de décomposition, cette température étant inférieure à la première température de fusion; (ii) chauffer le mélange à une température inférieure à la température de décomposition pour au moins durcir l'agent liant afin d'obtenir une structure solide; (iii) chauffer la structure solide à au moins la température de décomposition pour décomposer proprement l'agent liant et obtenir une structure poreuse à cellules ouvertes non frittée; et (iv) chauffer le corps poreux à cellules ouvertes non fritté à une température inférieure à la première température de fusion pour fritter les particules métalliques et obtenir un corps poreux à cellules ouvertes fritté pouvant être façonné en une structure métallique poreuse à cellules ouvertes de mèche.
PCT/CA2010/000580 2009-04-23 2010-04-23 Dispositif de transfert de chaleur à structure de mèche métallique poreuse à cellules ouvertes WO2010121365A1 (fr)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013143568A1 (fr) * 2012-03-29 2013-10-03 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Système de refroidissement pour système électrique
CN107225376A (zh) * 2017-06-21 2017-10-03 杭州瀚亨实业有限公司 一种微型超薄热管的生产工艺
CN110477456A (zh) * 2019-08-02 2019-11-22 深圳麦克韦尔科技有限公司 多孔结构组件和电子烟
CN110584208A (zh) * 2019-09-06 2019-12-20 深圳麦克韦尔科技有限公司 雾化芯、雾化器和电子雾化装置
CN111128435A (zh) * 2018-10-31 2020-05-08 广州力及热管理科技有限公司 混合两种不同熔点金属粉末的电子浆料
CN111907001A (zh) * 2019-05-07 2020-11-10 慧隆科技股份有限公司 具有均温腔的模塑热传组件及其成形方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6660224B2 (en) * 2001-08-16 2003-12-09 National Research Council Of Canada Method of making open cell material
US20070034357A1 (en) * 2005-08-12 2007-02-15 Chuen-Shu Hou Heat pipe and method of producing the same
WO2007121575A1 (fr) * 2006-04-21 2007-11-01 Metafoam Technologies Inc. Matériau poreux à cellules ouvertes et procédé de fabrication de celui-ci
WO2009049397A1 (fr) * 2007-10-19 2009-04-23 Metafoam Technologies Inc. Dispositif de gestion thermique utilisant de la mousse inorganique

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6660224B2 (en) * 2001-08-16 2003-12-09 National Research Council Of Canada Method of making open cell material
US20070034357A1 (en) * 2005-08-12 2007-02-15 Chuen-Shu Hou Heat pipe and method of producing the same
WO2007121575A1 (fr) * 2006-04-21 2007-11-01 Metafoam Technologies Inc. Matériau poreux à cellules ouvertes et procédé de fabrication de celui-ci
WO2009049397A1 (fr) * 2007-10-19 2009-04-23 Metafoam Technologies Inc. Dispositif de gestion thermique utilisant de la mousse inorganique
WO2009049427A1 (fr) * 2007-10-19 2009-04-23 Metafoam Technologies Inc. Cellule ouverte, matériau poreux, et procédé pour, et mélange pour, fabriquer ceux-ci

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013143568A1 (fr) * 2012-03-29 2013-10-03 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Système de refroidissement pour système électrique
CN107225376A (zh) * 2017-06-21 2017-10-03 杭州瀚亨实业有限公司 一种微型超薄热管的生产工艺
CN111128435A (zh) * 2018-10-31 2020-05-08 广州力及热管理科技有限公司 混合两种不同熔点金属粉末的电子浆料
CN111907001A (zh) * 2019-05-07 2020-11-10 慧隆科技股份有限公司 具有均温腔的模塑热传组件及其成形方法
CN110477456A (zh) * 2019-08-02 2019-11-22 深圳麦克韦尔科技有限公司 多孔结构组件和电子烟
CN110584208A (zh) * 2019-09-06 2019-12-20 深圳麦克韦尔科技有限公司 雾化芯、雾化器和电子雾化装置

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