Heat pipes with improved performance under diverse thermal load distributions.

Abstract

To avoid that a groove is dried up when thermal loads are not uniformly distributed, or changed over time without making a heat pipe excessively large.SOLUTION: A heat pipe (1) includes a push-out shaped main body (10) having a plurality of longitudinal channels (3) having hollow bodies which are blocked at both ends, and filled with prescribed quantities of two-phase operation fluids, and the longitudinal channels have cross sections which are limited by a bottom part (76) formed of one tubular peripheral wall (75) of the shaped main body, and two longitudinal partitions (2) in a lateral direction. A circumferential transmission channel (6) which is arranged while traversing in a local axial direction (X), and connecting fluids between the longitudinal channels is arranged at a position along a longitudinal passage (PX) and / or at one end, the longitudinal partitions are partially or completely interrupted in a region of the circumferential channel, and a block ring (4) is arbitrarily selectively used.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a heat pipe and a heat transfer device, particularly for cooling a heating member.

Background Art

[0002] A heat pipe generally includes a central axial channel through which a working fluid in gaseous form moves, and longitudinal grooves that are intended to move the working fluid in liquid form along a direction opposite to the gas and extend axially and are distributed around the central axial channel.

[0003] In the case of a heat load that is not uniformly distributed around the heat pipe, the grooves act in very different ways, with the more demanded grooves sometimes drying out while others are hardly demanded. This phenomenon can also be the result of an uneven and changing distribution of heat sources and cold sources along the heat pipe, as is frequent in many applications of heat pipes (for example, heat pipe networks, distribution of heating radiators, smoothing the temperature distribution over a relatively large surface area).

[0004] In fact, this observation leads to making the heat pipe too large in order to avoid the grooves drying out when the heat load is not uniformly distributed or changes over time.

[0005] The inventors have tried to improve this situation.

Summary of the Invention

Means for Solving the Problems

[0006] For this purpose, a heat pipe (1) configured for use in low gravity or zero gravity is proposed, comprising a shaped body (10) obtained by extrusion as a whole, the shaped body extending along a longitudinal path (PX), the shaped body forming a hollow body closed at at least two ends by a closing element, thereby forming an internal space hermetically isolated from the external environment and filled with a predetermined volume of two-phase working fluid, The shaped body described above includes a plurality of longitudinal channels (3) (actually implemented as longitudinal grooves), each of which has a cross-section limited by a bottom (76) formed by a single tubular peripheral wall (75) of the shaped body, and by two longitudinal partitions (2) extending radially inward from the peripheral tubular wall in the lateral direction, the longitudinal channels enclose an axial channel (15) (for carrying gas), and the longitudinal channels open toward the axial channel. The invention is characterized in that a circumferential transfer channel (6) is provided at at least one first position (P1) along a longitudinal path (PX), which is arranged across a local axial direction (X) and provides interfluid connections between all or some of the multiple longitudinal channels, and the longitudinal partition is interrupted, partially or completely, in the region of the circumferential channel.

[0007] Thanks to these features, grooves adjacent to one or more grooves under maximum demand for liquid fluid supply can be contributed to by circumferential transfer channels. The liquid passes through the circumferential transfer channels from grooves under lower demand conditions to grooves under higher demand conditions. In this way, a contribution is made to push back against the thermal load limits that could lead to partial or complete drying of one or more grooves under maximum demand conditions. The part under maximum thermal demand is the one with the largest evaporation flow / flow rate.

[0008] It should be noted that the longitudinal path (PX) does not have to be straight. If the path is not straight, the axial direction is therefore local and not absolute.

[0009] It should be noted that the circumferential transmission channel (6) is generally observed as annular passages. In fact, it is most commonly observed as annular grooves.

[0010] It should be noted that longitudinal channels are generally manufactured as longitudinal grooves, produced together with the main shaped body, as a result of extrusion.

[0011] It should be noted that a circumferential transfer channel can fluidly communicate with all longitudinal channels, and for this purpose the annular passage effectively makes a complete turn. However, in specific configurations of known thermal loads, it is not excluded that a circumferential transfer channel fluidly communicates with longitudinal channels over half the circumference (only half a turn) or over one or more arbitrary angular ranges.

[0012] It should be noted that the cross-section of a longitudinal channel can take on a variety of possible shapes, as the bottom is not necessarily flat and the partitions are not necessarily straight. In a particular example, the cross-section of the longitudinal channel has an overall concave shape. In a particular example, the cross-section of the longitudinal channel can be a roughly circular or elliptical arc. In a particular example, the cross-section of the longitudinal channel can be trapezoidal.

[0013] In various embodiments of the present invention relating to the method, it is potentially possible to employ one and / or another of the following configurations individually or in combination.

[0014] According to one option, the circumferential channel completes a full rotation, fluidizing all longitudinal channels. Thus, homogeneous and predictable behavior is possible regardless of the load distribution around the heat pipe. Wherever the circumferential region has the greatest thermal load, the groove under the greatest thermal demand receives additional fluid from other grooves via the circumferential transfer channel.

[0015] According to one option, several circumferential transmission channels can be arranged sequentially along the longitudinal direction. In this way, the liquid redistribution effect can be increased, and the capillary pressure can be increased throughout the entire zone.

[0016] According to one option, depending on the specific groove dimensions, for example, particularly for very narrow circumferential grooves, it is possible to transition from the covering ring discussed just below.

[0017] According to one option, the circumferential transmission channel can be radially confined internally by a covering ring, which is sandwiched between the circumferential transmission channel and the axial channel. Advantageously, the presence of the covering ring helps support the formation of a liquid meniscus on its walls and the walls of adjacent partitions. The presence of the covering ring helps increase the capillary pressure at this axial position of the heat pipe. Advantageously, the ring design is optimized to limit local load losses in longitudinal flow, for liquids or gases.

[0018] According to one option, the circumferential channel can be positioned at an intermediate location, and the partition (2) is interrupted in this region over a predetermined length (L6). Thus, for the circumferential channel at the intermediate location, it can be implemented as an annular passage by means of material removal operation with a rotary tool such as a centrifugal cutter, or by electrolysis or other common machining techniques.

[0019] According to one option, in the region of the circumferential channel, the material of partition (2) is preferably removed over a height (H6) that falls between 50% and 100% of the partition height (H2).

[0020] According to one option, in the region of the circumferential channel, partition feet remain over the residual height (H7) which falls between 0% and 50% of the partition's normal height (H2). Retaining partition feet helps to preserve the longitudinal contact line for transporting the liquid by capillary action despite the presence of the circumferential transmission channel.

[0021] According to one option, the partition may include a first support zone (B1) for receiving a first longitudinal end of the covering ring (4) and a second support zone (B2) for receiving a second longitudinal end of the covering ring. In this way, the ring is securely held in place on the support zones relative to the partition on both sides of the circumferential transmission channel.

[0022] According to one option, the covering ring (4) may include a central extra thickness (45) that forms a radially outward shoulder received between the partitions in the region of the first and second support zones (B1, B2). This is a simple and robust solution, as machining the annular throat is relatively easy and such a ring with the extra thickness can be obtained with standard slewing / metalworking.

[0023] According to one option, the covering ring (4) can have a certain thickness, and the first and second support zones are formed as recessed flat regions (14) from the apex of the partition. By means of forming a circumferential channel using a suitable cutter or two machining paths, the ring is a simple cylinder obtained by cutting a tube, which is then a very good value part.

[0024] According to one option, the covering ring (4) can be made of a deformable material in either the elastic or plastic field, so that the covering ring can be inserted through the whole from one end of the shaped body to the first and second support zones, and as a result, at the target position, the covering ring closes the circumferential transmission channel radially inwards. At the target position, the elasticity is released, or a plastic force (deformation) is applied outwards to permanently set the arrangement.

[0025] According to one option, the first position (P1) is selected near the evaporation part (71) of the heat pipe coupled to the heat source (81). Thus, the pressure equalization of the liquid phase in the longitudinal channel is optimized closest to the zone where it is best to avoid drying under heavy heat loads.

[0026] According to one option, the first position (P1) is an intermediate position along the longitudinal path. Since this intermediate position is arbitrary along the longitudinal path, the arrangement of the circumferential transmission channel (or circumferential channels) can thus be freely selected closest to the required location.

[0027] According to one option, the first position (P1) is an end position on the longitudinal path. In this configuration, it is easier to remove material from the partition to form the annular throat forming the transmission channel.

[0028] According to one option, the circumferential channel is formed in an end cap (5) fixed to one end of the shaped body. In this configuration, no reprocessing operation is performed on the shaped body coming from extrusion. The complexity of the shape and installation is created by the end cap.

[0029] According to one option, one or more other circumferential channels are provided at an axial position different from the first position on the path. The plurality of positions are advantageously determined as a function of its application or can be uniformly distributed along the longitudinal direction over all or part of the heat pipe.

[0030] According to one option, the heat pipe can include a combination of circumferential channels, some of which are arranged at intermediate longitudinal positions and some of which are arranged at end positions. In other words, even if several different types of circumferential channels coexist, it does not lead to incompatibility.

[0031] According to one option, the heat pipe can include a combination of different types of circumferential channels. For example, there can be an annular channel (360°) on the condenser side and a partial annular channel (<360°) on the evaporator side. Given the heat load distribution, the circumferential channels can be adapted to optimize the thermohydraulic performance.

[0032] According to one option, a plurality of circumferential channels can be provided along the length at uniformly spaced axial positions (P2, P3, P4) with a given step, for example every 300 millimeters. This helps to equalize the pressure of the liquid phase in all the grooves at regular intervals along the heat pipe.

[0033] According to one option, one or more intersections with two circumferential channels arranged on both sides of each intersection can be provided along the length of the heat pipe. In this way, the supposed adverse effects of the intersections from the perspective of the hydraulic continuity between the channels are minimized.

[0034] According to one option, the heat pipe can be made like a three-dimensional object. At this time, it extends not only in a plane but also in a three-dimensional Cartesian space. Advantageously, this provides overall freedom in design and configuration to fully address all possible applications.

[0035] Advantageously, in the proposed solution, the proposed heat pipe lacks any perforated layer, perforated mass, or perforated covering, either locally or overall, along the length of the heat pipe. In other words, the proposed heat pipe does not have any capillary perforated material intended to provide capillary pumping.

[0036] Other aspects, objectives, and advantages of the present invention will become apparent upon reading the following description of one embodiment of the present invention, which is given without limitation for illustrative purposes. The present invention will be better understood in light of the accompanying drawings. [Brief explanation of the drawing]

[0037] [Figure 1] This diagram schematically shows a heat pipe connected to a heat source on one side and a cold source on the other. [Figure 2] This diagram schematically shows a heat pipe that is connected to a heat source on one end at an intermediate position and to two cold sources at its ends. [Figure 3] This diagram schematically shows a heat pipe connected to a continuous cold source along its upper length and to a heat source at its lower end, and a configuration called a "heat spreader." [Figure 4] This figure shows a substantially cross-sectional view of a shaped body according to one embodiment, along the cutting line IV shown in Figure 7. [Figure 5] This is a diagram showing a vertical cross-section of the shaped body. [Figure 6] This figure shows a cross-section of the heat pipe near the circumferential transfer channel along the cutting line VI shown in Figure 7. [Figure 7] This figure shows a longitudinal cross-section of a heat pipe in the region of a circumferential transfer channel. [Figure 8] This figure shows a cross-section of the heat pipe in the region of the circumferential transfer channel along the cutting line VIII shown in Figure 7. [Figure 9] This figure shows a longitudinal half-section of a heat pipe in the region of a circumferential transfer channel. [Figure 10]Similar to Figure 7, this figure shows a longitudinal cross-section of a heat pipe in the region of a circumferential transmission channel for one modified implementation configuration. [Figure 11] This figure shows a cross-section of the heat pipe along the cutting line XI shown in Figure 12. [Figure 12] This figure shows a longitudinal cross-section of the heat pipe in the region of one end with a fitted cap, along the cutting line XII shown in Figure 11. [Figure 13] This figure shows various shapes of the meniscus of the liquid phase of the working fluid inside the longitudinal channel. [Figure 14] This figure shows various shapes of the liquid phase meniscus of the working fluid inside the circumferential transmission channel. [Figure 15] This figure shows a longitudinal cross-section of a heat pipe in one end region, equipped with a fitted cap, in a modified mounting configuration. [Figure 16] This figure shows a cross-section of the shaped body according to the second embodiment. [Figure 17] This diagram shows a more detailed geometric example of a longitudinal channel and the partition adjacent to it. [Figure 18] This figure shows an example of a typical heat pipe path in which the present invention can be implemented. [Figure 19] This figure shows a longitudinal half-section of a heat pipe in a region of right-angle connection with two circumferential transfer channels. [Figure 20] This figure shows a longitudinal half-section of a heat pipe in a cross-connection region with four circumferential transmission channels. [Modes for carrying out the invention]

[0038] In various diagrams, the same symbols refer to the same or similar items. For the sake of clarity of disclosure, some elements are not necessarily shown at a consistent scale.

[0039] The heat pipe 1 shown in Figure 1 collects heat from a heat source 81 and releases it to a cooling source 82. The heat source 81 is in contact with the heat pipe near the evaporation section 71. The cooling source 82 is in contact with the heat pipe near the condensation section 72.

[0040] The heat pipe 1 is viewed as a long device closed at a first end 11 by a closing element 50 and at a second end 12 by a second closing element 50.

[0041] Figure 2 shows another example where a heat pipe receives heat at one middle section and releases this heat at two ends.

[0042] Figure 3 shows another example in which a heat pipe receives heat from one side of its axis (from the bottom in the illustrated example) and releases this heat from the other side of its axis (from the top in the illustrated example). This involves a configuration known in the art as a "heat spreader".

[0043] The heat pipe 1 generally includes a central axial channel 15 through which the working fluid moves in gaseous form, with longitudinal grooves extending axially and around the central axial channel. As shown in Figures 4 and 5, the longitudinal grooves, also called longitudinal channels 3, are intended to move the working fluid forward in liquid form along the opposite direction to the gas.

[0044] Heat pipe 1 is configured for use in low gravity or weightlessness. For example, this heat pipe is used in equipment and devices sent into space. In particular, this type of heat pipe is used in communication satellites, surveillance satellites, and satellites with all kinds of other functions. Heat pipe 1 can be used in complete weightlessness or low gravity conditions, for example, on the surface of a celestial body such as the Moon or Mars. Heat pipe 1 can be used at zero or very low external pressure.

[0045] Basic shape The heat pipe 1 includes a shaped body 10 obtained by extrusion. Additional operations can also be performed, as will be seen later. However, the extrusion operation is the main operation in manufacturing. An aluminum alloy is pressed by a press through a die having the intended shape to obtain a shaped body at the die exit.

[0046] In the examples shown in Figures 4 to 11, the shaped body defines an internal space that is airtightly isolated from the external environment and forms a hollow body used to contain the working fluid.

[0047] The shaped body, after extrusion, has a cross-section that extends uniformly along the longitudinal axis referenced by X. The shaped body can also be bent at this stage, so the final heat pipe is not necessarily straight.

[0048] Generally, the shaped body 10 extends along the longitudinal path PX. The longitudinal path PX may be a straight line or a curve.

[0049] The length of path PX can be between 0.5m and 10m.

[0050] The shaped body 10 includes a peripheral tubular wall 75 from which two opposite legs 16, 17 extend radially outward. Each of these legs terminates on a support plane suitable for exchanging heat with a cold source or heat source 82, 81.

[0051] In another configuration, there may be only one leg for thermal coupling and only one support plane, one leg designed to incorporate an integrated or mechanical function, or there may be no legs at all.

[0052] In another configuration, it may have four interface planes, and in specific cases the outer limit of the body may be substantially square or perfectly cylindrical.

[0053] In yet another configuration, the thermal coupling elements may be separate or added, as shown in Figure 16. In this case, the shape is generally a rotation around the X-axis, with a circumferential repetition of the inner [groove + partition] pattern.

[0054] The shaped body includes multiple longitudinal channels 3. In practice, the longitudinal channels are manufactured as longitudinal grooves.

[0055] Each of the longitudinal channels described above has a cross-section defined by a bottom 76 formed by the peripheral tubular wall 75 of the shaped body, and by two longitudinal partitions 2 extending radially inward from the peripheral tubular body in the lateral direction.

[0056] The longitudinal channels surround the central axial channels 15 that carry the gas. The longitudinal channels 3 are generally open in the direction of the axial channels.

[0057] The illustrated example has 16 longitudinal partitions 2 and 16 longitudinal channels 3. Generally, the number of longitudinal channels falls between 6 and 48.

[0058] The longitudinal channels 3 are arranged in a ring around the axis. However, non-circular arrangements are also possible.

[0059] The peripheral tubular wall 75 has a basic outer diameter D0. D0 can be between 3 mm and 50 mm.

[0060] The diameter D1 represents the inner dimension of the surrounding tubular wall 75, in other words, the diameter near the bottom of the groove.

[0061] The diameter D2 represents the internal dimension of the axial channel, in other words, the diameter of the circumscribed circle passing through the top 77 of the partition.

[0062] It should be noted that this shape is made from a single piece, and since everything is extruded together, the interior space is completely airtightly isolated from the external environment throughout the entire shaped body, thus enclosing the interior space continuously without opening.

[0063] Thus, the sealing problem must be addressed only in the regions of the longitudinal ends 11 and 12. The case of connection by joining contours will be examined later.

[0064] The working fluid can be ammonia, propylene, methanol, or any other medium that has a liquid-gas equilibrium state saturated at an operating pressure defined by temperature. A fixed amount of working fluid is applied through one of the end elements equipped with a sealable injection opening. The pressure prevailing in the internal space of the heat pipe can range from 0.1 bar to several tens of bar.

[0065] A certain amount of working fluid is defined to have a groove that is preferably confined, i.e., completely filled, from the cold / condenser side, and, where applicable, to fill the axial end of the channel on the cold side.

[0066] It should be noted that the cross-section of the longitudinal channel 3 can take any suitable shape, since the bottom 76 is not necessarily flat and the partitions are not necessarily straight. Preferably, the cross-section of the longitudinal channel has an overall recess. In a particular example, the cross-section of the longitudinal channel can be a roughly circular or elliptical arc, or even a teardrop shape opening toward the axial channel 15. In the example shown in the figure, the cross-section appears as a trapezoidal cross-section.

[0067] Passageway / circumferential channel Advantageously, at least one circumferential transmission channel 6 is provided, which is positioned across the local axial direction. The circumferential transmission channel 6 is located at a first location P1 along the longitudinal path PX.

[0068] We will examine below some possibilities for this position P1 along the longitudinal path PX.

[0069] The circumferential transmission channel 6 provides interfluid communication between all longitudinal channels. More generally, the circumferential transmission channel 6 provides interfluid communication between all or some of the multiple longitudinal channels.

[0070] The circumferential transmission channel 6 is typically seen as an annular passage or groove. In practice, it is often seen as an annular throat that creates a complete ring (360°) without excluding smaller angular openings.

[0071] Referring to Figures 7, 10, and 17, note that the longitudinal partition 2 is interrupted in the region of the circumferential channel 6. The partition material was removed over a depth of H6. Along axis X, the circumferential transmission channel 6 has an axial length L6.

[0072] The axial length L6 of the circumferential channel can be greater than the groove height H2, as shown in the illustrated example.

[0073] In other configurations, the axial length L6 of the circumferential channel can be less than the groove height H2.

[0074] In the illustrated example, part of the partition was not removed (this corresponds to the remaining height H7 = H2 - H6).

[0075] For example, H6 can be between 50% and 100% of height H2. For example, H6 can be between 70% and 100% of height H2.

[0076] In other configurations, the entire height of the partition may be removed (hence H7=0).

[0077] In reality, the partition feet remain over the remaining height H7, which is contained between 0% and 50% of the partition height H2. Retaining the partition feet helps to preserve the longitudinal contact line for transporting the liquid by capillary action, despite the presence of circumferential transmission channels.

[0078] It should be noted that several circumferential transmission channels can be arranged sequentially along the longitudinal direction X. It is also possible to plan for the implementation of fairly tight, continuous transverse channels with small longitudinal dimensions (small L6).

[0079] It should be noted that there are no perforated layers, perforated masses, or perforated coverings in one or more circumferential transfer channels, either locally or overall, along the length of the heat pipe. The proposed heat pipe does not have any capillary perforated material intended to provide capillary pumping, and is therefore easy to manufacture.

[0080] Covering ring According to one favorable option, the circumferential transmission channel 6 is radially restricted internally by a covering ring 4. The covering ring 4 is sandwiched between the circumferential transmission channel and the axial channel. The covering ring 4 closes the circumferential transmission channel 6 radially toward axis X.

[0081] The covering ring 4 is usually seen as a tubular body 40, or sometimes called a sleeve.

[0082] The covering ring 4 has an axial length L5. The axial length L5 of the covering ring is actually selected to be slightly larger than the axial length L6 of the circumferential channel.

[0083] Near the circumferential transmission channel, the radial thickness E5 of the covering ring falls between 0.1 mm and 1 mm.

[0084] In its position for use, the inner diameter of the ring is referenced by D4.

[0085] The outer diameter of the ring near the circumferential channel is referred to as D5.

[0086] Covering ring 4 can be made of a deformable material in either an elastic or plastic region so as to be installed at a predetermined position to cover and close the circumferential channel 6 in the radial direction.

[0087] According to the option of elastic deformation, the ring is radially inwardly constrained and then inserted inside the axial channel by a screw, and after arriving at the correct axial position (i.e., the target position), the elastic constraint is released, which leads to expansion and the final arrangement.

[0088] According to the option of plastic deformation, the initial diameter of the ring is selected to be slightly smaller than D2, and then the ring is inserted inside the axial channel by a screw, and after arriving at the correct axial position (i.e., the target position), radial expansion is caused by inserting a deformable tool. Then the covering ring becomes flat against a partition or a support / flat surface provided for this purpose.

[0089] A first support zone B1 for receiving the first longitudinal end 41 of the covering ring 4 and a second support zone B2 for receiving the second longitudinal end 42 of the covering ring are provided to receive the covering ring in the zone of the circumferential channel.

[0090] [[ID=2L]]According to the first solution shown in FIGS. 7 and 9, the covering ring 4 can include a central excessive thickness 45 that forms a radially outward shoulder 。The central excessive thickness 45 is received between partitions on the stop edge 44 in the regions of the first and second support zones.

[0091] Note that in this configuration, D4 < D2 < D5.

[0092] According to the second solution shown in Figure 10, the covering ring has a constant thickness E4, and the first and second support zones B1 and B2 are formed as recessed flat regions 14 from the top of the partition.

[0093] In this case, note that the diameter D4 is greater than D2, meaning the ring is radially recessed from the vertex 77 of the partition.

[0094] The flat region 14 is obtained by removing material.

[0095] The covering ring forms an additional line of contact, which increases the capillary pressure near the circumferential channel 6. Therefore, the capillary pressure near the circumferential channel 6 is greater than the capillary pressure along the longitudinal channel 3. To ensure the continuity of the liquid flow, the ring allows for the complete recovery of the hydraulic section, in this case the circumferential channel.

[0096] cap In the case of a standard heat pipe end, the closing element 50 simply closes the shaped body. However, the present invention requires the skillful use of the closing element.

[0097] According to one embodiment, the circumferential channel is formed in an end cap 5 fixed to one end of a shaped body.

[0098] According to the first cap solution shown in Figure 12, the cap includes an inner sleeve 51 and a closing disc 52. The disc is welded / sealed at the end of the shaped body 10 near an airtight joint 53 for secure mounting. The closing disc 52 is thick enough to withstand internal pressure. On the other hand, the inner sleeve 51 does not support any substantial force, and it is sufficient that the axial length L65 of the sleeve is greater than the axial length L6 of the circumferential channel so that it is coplanar with the vertex 77 of the wall 2.

[0099] The circumferential channel 6 is obtained by removing material from the partition at its end. This machining is relatively standard and is sufficient by inserting a cutter at the end of the body 10 with a diameter defined in the axial direction.

[0100] According to the second cap solution shown in Figure 15, the cap includes an inner sleeve 51. The inner sleeve 51 is separate from the closing disk 52, etc., and can be manufactured according to a single-unit approach. When it is separate, the inner sleeve 51 is received in the bottom circular housing 57 of the closing disk and appears as an easily obtainable part, a simple tubular sleeve.

[0101] Here again, a sealed closing joint 53 is provided to connect the outer collar 54 of the cap 5 to the shaped body 10.

[0102] Note here that the longitudinal partition 2 is interrupted in the region of the circumferential channel. The outer limit of the circumferential channel is formed by the thickness 56 of the cap that protrudes radially inward.

[0103] Operation and other specifications In a weightless environment, gravity is negligible compared to the forces caused by capillary action. Therefore, the physical phenomenon of capillary action prevails, accompanied by forces and pressures applied to the various liquid parts present in the heat pipe.

[0104] A first position P1 for the circumferential transfer channel is selected near the evaporation section 71 to which the heat pipe is coupled to the heat source. The circumferential transfer channel is filled with liquid, and the pressure difference between the different grooves is equal in that region.

[0105] Meniscus Ms are formed in the longitudinal channels, and these indent further along the grooves, especially when the pressure difference is greater in the longitudinal direction between the cold source corresponding to the lowest pressure and the hot source corresponding to the highest pressure.

[0106] Therefore, in Figure 13A, the meniscus is almost flat. In Figure 13B, the meniscus is more depressed. In Figure 13C, the meniscus is even more depressed.

[0107] A meniscus is formed in the circumferential transfer channel, allowing the liquid to move in the circumferential direction and pass from one longitudinal channel to another.

[0108] As shown in Figure 14A, a meniscus is formed at the start of the ring and at the bottom of the longitudinal channel. Figure 14B shows a stable morphology in which the entire volume of the circumferential transmission channel is filled with liquid.

[0109] In other words, the meniscus is only temporarily formed in circumferential channels, and in established forms, it is the longitudinal channel meniscus, which is more sloping downstream than upstream, that generates the flow in the circumferential groove.

[0110] Thus, the recirculation groove is designed to have greater capillary pumping than the longitudinal groove to ensure proper liquid injection.

[0111] Referring to Figure 16, channel C1 is under maximum heat demand, receiving heat through the short conductive channel, and this is the region where the evaporation flow rate is highest. The adjacent channels C2, CG also participate in vaporization, but slightly less. The slightly more distant channels C2, CG and beyond participate in vaporization, depending on the intensity of the heat flow, to the point where, for the furthest channel, they no longer participate in vaporization at all when all the incoming flow has evaporated. Advantageously, the presence of circumferential transfer channels near the heat source helps to pass liquid that did not reach C1 over its length toward channel C1. In other words, adjacent channels supply liquid to the first channel C1.

[0112] Not only direct or indirect neighboring channels, but all other channels can be involved in providing liquid to avoid localized drying at the point of maximum demand.

[0113] In the case of a top load as shown in Figure 16, channels CG, C1, and C2 will be supplied by all other channels, namely C3, C4, C5, C6, C7, C8, C9, CA, CB, CC, CD, CE, and CF.

[0114] To put it differently, the circumferential transmission channel has the function of connecting and sharing the liquid supply. It supplies liquid from the other channels to the longitudinal channel 3, which is most needed.

[0115] Various other points The closing ring supports the supply of fluid through the circumferential transmission channel.

[0116] The ring also supports passage along a straight line in a specific longitudinal channel.

[0117] If the closing ring is slightly retracted compared to the top of the partition, this has a favorable effect on the straight-line passage of liquid in the longitudinal channel.

[0118] Furthermore, one or more other circumferential channels are provided at separate axial positions (P2, P3, P4) on the path that are different from the first position (P1).

[0119] As shown in Figure 18, the path PX may include one or more curves 18 and, when applicable, one or more right angles 19.

[0120] Figure 19 shows a longitudinal half-section of a heat pipe in a region of right-angle connection with two circumferential transfer channels. In the illustrated case, two shaped bodies are joined end-to-end at a 45° angle to form a right angle in this region, resulting in an imbalance in meniscus formation between the well-moistened outer groove and the somewhat drier inner groove. The presence of one or two circumferential transfer channels in this angular region helps to equalize pressure between the various longitudinal channels.

[0121] Figure 20 shows a longitudinal half-section of the heat pipe in a cross-connection region with four circumferential transmission channels. This configuration complements the previous case shown in Figure 19, where the four contours are joined end to end at a cross intersection. The presence of four circumferential channels in this angular region helps to equalize pressure between the various longitudinal channels.

[0122] Near the intersection, an external mounting sleeve is expected, which ensures a mechanical connection and seal, generally obtained by welding.

[0123] Regarding dimensional considerations, L6 can be selected to fall between 0.1D0 and 0.5D0. It is also observed that D0 > D1 > D2. For the partition height, a value for H2 can be selected that falls between 0.05D1 and 0.2D1. [Explanation of symbols]

[0124] 1 Heat pipe 2 partitions 3 Longitudinal Channels 4 Covering Rings 5 End caps 6. Circumferential transmission channels 10 Shaped Body 11 First end 12 Second end 14 flat area 15 Central axis channel 16 Legs 17 Legs 18 Curves 19 right angle 40 Tubular body 41 First longitudinal end 42 Second longitudinal end 44 Stop edge 45. Excessive central thickness 47 Radial outward-facing shoulder portion 50 Closure elements 51 Inner sleeve 52 Closing disk 53 Airtight joint 54 Outer color 56 Cap thickness 57 Circular bottom housing 71 Evaporation portion 72 Condensed portion 75 Peripheral tubular wall 76 Bottom 77 Top 81 Heat source 82 cold source

Claims

1. A heat pipe (1) comprising a shaped body (10) and configured for use in low gravity or zero gravity, The shaped body extends along a longitudinal path (PX) and forms a hollow body that is closed at at least two ends by a closing element, thereby hermetically isolating it from the external environment and forming an internal space filled with a predetermined volume of two-phase working fluid. In a heat pipe, the shaped body includes a plurality of longitudinal channels (3), each longitudinal channel having a cross-section defined by a bottom (76) formed by a single tubular peripheral wall (75) of the shaped body and two longitudinal partitions (2) extending radially inward from the tubular peripheral wall in the lateral direction, the longitudinal channels surround an axial channel (15), and the longitudinal channels open toward the axial channel, A circumferential transmission channel (6) is provided at at least one first position (P1) along the longitudinal path (PX), which is arranged across the local axial direction (X) and provides mutual fluid connections between all or some of the plurality of longitudinal channels. The longitudinal partition is partially or completely interrupted in the region of the circumferential transmission channel. A heat pipe characterized in that the circumferential transmission channel is radially defined on the inside by a covering ring (4), and the covering ring is sandwiched between the circumferential transmission channel and the axial channel (15).

2. The heat pipe according to claim 1, characterized in that the circumferential transmission channel may be positioned at an intermediate location, and the partition (2) is interrupted in this region over a predetermined length (L6).

3. The heat pipe according to claim 2, characterized in that the partition comprises a first support zone (B1) for receiving the first longitudinal end (41) of the covering ring (4) and a second support zone (B2) for receiving the second longitudinal end (42) of the covering ring.

4. The heat pipe according to claim 3, characterized in that the covering ring (4) has a central excess thickness (45) that forms a radially outward shoulder portion received between the partitions in the region of the first and second support zones (B1, B2).

5. The heat pipe according to claim 3, characterized in that the covering ring (4) has a certain thickness, and the first and second support zones are formed as recessed flat regions (14) from the apex of the partition.

6. The heat pipe according to any one of claims 1 to 5, characterized in that the first position (P1) is selected near the evaporation portion (71) of the heat pipe coupled to the heat source (81).

7. The heat pipe according to any one of claims 1 to 6, characterized in that the first position (P1) is an intermediate position along the longitudinal path (PX).

8. The heat pipe according to any one of claims 1 to 6, characterized in that the first position (P1) is an end position on the longitudinal path.

9. The heat pipe according to any one of claims 1 to 6, characterized in that the circumferential transmission channel is formed in an end cap (5) fixed to one end of the shaped body.

10. The heat pipe according to any one of claims 1 to 9, characterized in that one or more other circumferential channels are provided at separate axial positions (P2, P3, P4) on the longitudinal path that are different from the first position.

11. A heat pipe according to any one of claims 1 to 9, characterized in that a plurality of circumferential channels can be provided along its length at uniformly spaced axial positions (P2, P3, P4) with predetermined steps.

12. A heat pipe according to any one of claims 1 to 11, characterized in that two circumferential channels each have one or more intersections located on either side of them.

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