A thermosyphon fin plate

Abstract

The present invention provides a thermosyphon fin plate, comprising two thin plates butted together and a thermosyphon formed between the two thin plates; the thermosyphon comprises: a channel of an evaporator / rising pipe, a gas-liquid distributor channel, a channel of a condenser / return pipe, and a channel with a slit; the channel of the evaporator / rising pipe is arranged at the edge of the root of the thermosyphon fin plate; the gas-liquid distributor channel is arranged at the top of the channel of the evaporator / rising pipe, and the top of the channel of the evaporator / rising pipe is connected to the top of the channel of the condenser / return pipe; the liquid collector channel is located at the bottom of the channel of the condenser / return pipe, and is connected to the channel of the evaporator / rising pipe through the channel with a slit. The thermosyphon fin is made of a material with very high electrical conductivity, and the efficiency of the thermosyphon fin is 25% or more higher than that of an equivalent solid fin, so as to make it closer to the efficiency of an ideal fin.

Description

Technical Field

[0001] The invention relates to the technical field of thermosyphons, and in particular to a thermosyphon fin plate. Background Art

[0002] In the prior art, electronic planar cooling plates with a large number of electronic components to be cooled are basically air-cooled devices, or air-cooled devices assisted by heat pipe devices. In order to increase the cooling rate, these planar cooling plates are sometimes attached with extended surfaces to increase their heat transfer surface area in contact with the cooling airflow, which is usually called heat sink or fin. The heat on the planar cooling plate is removed by conducting most of the heat to the fins and then dissipating this heat into the airflow. Since the heat conduction on the fins is only through thermal conduction, the heat flows only in the direction of lower temperature, so the surface farther away from the root of the fin has a worse effect, and the surface closer to the root has a better effect. Generally, the thermal performance of the fin is defined by the heat sink efficiency, in which the heat removed from the actual fin is compared with the ideal theoretical fin, where the entire surface of the ideal theoretical fin is at the same temperature as the root, and the heat sink efficiency is 100%. For long fins, the efficiency of the fin drops significantly below 100% (for example, to 20-40%), making the efficiency of the fin quite low and not cost-effective. This can occur even with highly conductive metals such as aluminum when the fins are very long.

[0003] In the prior art, the heat dissipation efficiency of the fins is low. Summary of the invention

[0004] In order to solve the existing problems, the present invention provides a thermosyphon fin plate.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] A thermosyphon fin plate comprises two thin plates butted together and a thermosyphon tube formed between the two thin plates; the thermosyphon tube comprises: an evaporator / rising pipe channel, a gas-liquid distributor channel, a liquid collector channel, a condenser / return pipe channel, and a channel with a slit; the evaporator / rising pipe channel is arranged at the edge of the root of the thermosyphon fin plate; the gas-liquid distributor channel is arranged at the top of the evaporator / rising pipe channel, and the top of the evaporator / rising pipe channel is connected to the top of the condenser / return pipe channel; the liquid collector channel is located at the bottom of the condenser / return pipe channel, and is connected to the evaporator / rising pipe channel through the channel with a slit.

[0007] Preferably, the cross-sectional area of ​​the thermosiphon between the two thin plates is circular, rectangular with curved corners, or elliptical.

[0008] Preferably, the channels of the evaporator / rising pipe and the channels in the condenser / return pipe have a depth of 0.5 mm to 3 mm and a width of 0.5 mm to 3 mm.

[0009] Preferably, the depth and width of the gas-liquid distributor channel and the liquid collector channel are the same or different, with the depth ranging from 0.5 mm to 3 mm and the width ranging from 3 mm to 15 mm.

[0010] Preferably, the evaporator / rising pipe has at least one channel, and the number of channels of the condenser / reflux pipe is at least 5 times the number of channels of the evaporator / rising pipe.

[0011] Preferably, the cross-sectional area of ​​the channel with the slit is significantly smaller than the cross-sectional area of ​​the liquid collector channel and the channel of the evaporator / riser pipe.

[0012] Preferably, the width, diameter or cross-sectional area of ​​the channel of the evaporator / riser tube is uniform in its upward direction; or, the size of the cross-sectional area increases from the bottom to the top of the thermosyphon fin plate.

[0013] Preferably, the size of the cross-sectional area increases by 1.5-3 times from the bottom to the top of the thermosyphon fin plate.

[0014] Preferably, the cross-sectional area of ​​the gas-liquid distributor channel is 2-10 times the cross-sectional area of ​​the channel of the evaporator / rising pipe or the channel of the condenser / reflux pipe; the cross-sectional area of ​​the liquid collector channel is 2-10 times the cross-sectional area of ​​the channel of the evaporator / rising pipe or the channel of the condenser / reflux pipe.

[0015] Preferably, the cross-sectional area of ​​the channel with the slit is 1 / 2-1 / 10 of the cross-sectional area of ​​the evaporator / riser pipe channel.

[0016] The beneficial effects of the present invention are as follows: providing a thermosyphon fin plate, by butting two thin plates together, and forming a novel thermosyphon flow loop through the channels of the evaporator / rising pipe, the gas-liquid distributor channel, the condenser / return pipe channel, the liquid collection channel and the channel with slits between the two thin plates, for transferring heat from the root of the thermosyphon fin plate, and distributing the heat to the tip of the fin, and extending to the rest of the fin. By transferring heat to the tip of the fin with a very small temperature gradient relative to the temperature of the root of the fin, the thermosyphon fin is made of a very high conductivity material, and the efficiency of the thermosyphon fin is 25% or more higher than that of an equivalent solid fin, so as to make it closer to the efficiency of an ideal fin. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1Schematic diagram of the structure of a loop thermosiphon in the prior art in an embodiment of the present invention.

[0018] Figure 2 Schematic diagram of the structure of a rectangular thermosyphon fin plate attached to a planar cooling plate in an embodiment of the present invention.

[0019] FIG. 3( a ) is a schematic diagram of a thermosyphon flow circuit of a thermosyphon fin plate in an embodiment of the present invention.

[0020] FIG. 3( b ) is a schematic diagram of a thermosyphon flow circuit of another thermosyphon fin plate in an embodiment of the present invention.

[0021] Figure 4 Schematic diagram of the structure of the gas-liquid distributor in an embodiment of the present invention.

[0022] Figure 5 Schematic diagram of the structure of a channel with a slit in an embodiment of the present invention.

[0023] FIG. 6( a ) is a schematic diagram of the structure of two thin plates spliced ​​together in an embodiment of the present invention.

[0024] FIG. 6( b ) is a partially enlarged schematic diagram of two thin plates spliced ​​together in an embodiment of the present invention.

[0025] FIG. 7( a ) is a schematic diagram of a channel of a slit in an embodiment of the present invention.

[0026] FIG. 7( b ) is a schematic diagram of a circular channel of a slit in an embodiment of the present invention.

[0027] FIG. 7( c ) is a schematic diagram of a rectangular channel of a slit in an embodiment of the present invention.

[0028] Among them, 1-evaporator / rising pipe, 2-gas-liquid distributor, 3-condenser / reflux pipe, 4-liquid collecting channel, 5-channel with slits, 6-root of fin, 7-tip of fin, 8-thermosyphon fin plate, 9-cooling plate. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved by the embodiments of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0030] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and circuit connection.

[0031] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] like Figure 1 , a schematic diagram of the structure of a loop thermosyphon (or simply thermosyphon) that can be used to cool electronic components. The thermosyphon consists of an evaporator located at the bottom, in which the liquid working fluid inside is partially evaporated into vapor to remove heat from the electronic equipment. The outlet of the evaporator is connected to a riser, which is a tube that absorbs the two-phase flow, and the liquid and vapor flow upward to the inlet of the condenser. The condenser removes heat from the two-phase flow by condensing the vapor back to the liquid phase. The outlet of the condenser is connected to the top of the return pipe, which is a pipe that transports the liquid downward back to the inlet of the condenser. The flow loop in the figure is counterclockwise and the direction of gravity is downward. The density of the two-phase flow of liquid and vapor in the riser is lower than that of the liquid flow in the return pipe. This is due to the pressure imbalance caused by the influence of gravity inside the thermosyphon, which causes the two-phase working fluid to flow. The buoyancy in the riser causes the fluid to flow passively upward, while the liquid in the return pipe flows passively downward, forming a continuous flow cycle inside the thermosyphon.

[0034] like Figure 2 Schematic diagram of the structure of a rectangular thermosyphon fin plate attached to a flat cooling plate is shown. The thermosyphon fin plate 8 is a relatively long fin, and the efficiency of the fin is significantly reduced, making the efficiency of the fin quite low and not cost-effective. This happens even for metals with high conductivity (such as aluminum).

[0035] As shown in Figures 3(a) and 3(b), the loop of the thermosyphon first passes through the channel (which may be one or more channels) of the evaporator / riser 1 vertically upward or at a certain angle along the root area of ​​the fin, absorbing the heat conducted from the cooling plate 9 into the root 6 of the fin. The working fluid partially evaporates in the channel of the evaporator / riser 1, and has buoyancy due to the bubbles in the flow, transferring the latent heat in the vapor upward to the upper area of ​​the thermosyphon fin plate 8, entering the gas-liquid distributor channel 2 for distribution, and then entering the channel of the condenser / return pipe 3, and the working fluid flows downward under the action of gravity, which may be vertically downward or at a certain angle. The evaporator / riser 1 of the thermosyphon is combined here into a single section called the evaporator / riser 1, instead of two separate sections in the usual thermosyphon. All vapors are condensed into liquid in the channel of the condenser / return pipe 3, dissipating heat to the outer surface of the thermosyphon fin plate 8 (i.e., the two surfaces of the thermosyphon fin plate 8), and the heat is taken away by the air flow. Therefore, the condenser / return pipe 3 also becomes a single part of the thermosyphon loop, referred to herein as the condenser / return pipe 3. At the bottom of the channel of the condenser / return pipe 3, a liquid collector channel 4 is added to the thermosyphon loop, which receives all liquid and transports it to the bottom of the channel of the evaporator / riser pipe 1, where the thermosyphon loop continues to flow. Between the outlet of the liquid collector channel 4 and the inlet of the channel of the evaporator / riser pipe 1, a channel 5 with a slit is introduced, and the cross-sectional area of ​​the channel 5 with a slit is significantly smaller than that of any of the liquid collector channel 4 and the channel of the evaporator / riser pipe 1 (usually at least 50% smaller). The slitted channel 5 serves to prevent vapor from flowing back from the channel of the evaporator / riser pipe 1 to the liquid collector channel 4 and also serves to stabilize the thermosyphon flow to prevent flow oscillations.

[0036] like Figure 7(a)-Figure 7(c) As shown, the channel 5 with slits can be a small diameter channel, a tapered channel, or a rectangular or circular shape formed by curling the channel. The width, diameter or cross-sectional area of ​​the channel of the evaporator / riser tube 1 can be uniform along its upward length, or the size of the cross-sectional area can increase from the bottom to the top of the thermosyphon fin plate 8, thereby promoting and enhancing the upward flow movement.

[0037] The present invention provides a thermosyphon fin having an evaporating and condensing working fluid inside. A novel thermosyphon flow loop is formed in the channels of the evaporator / rising pipe 1, the gas-liquid distributor channel 2, the condenser / return pipe 3, the liquid collection channel 4, and the channel 5 with slits of the thermosyphon fin, which is used to transfer heat from the root 6 of the fin, and spread the heat to the tip 7 of the fin, and extend to the rest of the fin. By transferring heat to the tip 7 of the fin with a very small temperature gradient relative to the temperature of the root 6 of the fin, the thermosyphon fin is made of a very high conductivity material, and the efficiency of the thermosyphon fin is 25% or more higher than that of an equivalent solid fin, so as to make it closer to the efficiency of an ideal fin.

[0038] The purpose of the present invention is to make the outer surface temperature of the thermosyphon fin plate 8 close to uniform and as close as possible to the root 6 temperature of the fin in the evaporator / riser tube 1 area, thereby greatly improving the surface temperature of the thermosyphon fin plate 8. Compared with the equivalent solid metal plate, the efficiency of the thermosyphon fin plate 8 is higher, so the heat transfer from the thermosyphon fin plate 8 to the outside air is greatly increased by about 40% or more. The outside airflow can be due to natural convection or driven by a fan.

[0039] As shown in Fig. 6(a) and Fig. 6(b), the thermosyphon fin plate 8 is formed of two thin plates, which are combined with an internal loop thermosyphon formed between the two thin plates. First, the two thin plates are punched to form a semicircular notch therein, so that when the two thin plates are combined together to form a single thermosyphon fin, a channel for the internal loop thermal weld is formed. The loop thermosyphon of the thermosyphon fin plate 8 is composed of the following components: (i) a channel of the evaporator / rising pipe 1, (ii) a gas-liquid distributor channel 2, (iii) a channel of the condenser / return pipe 3, including one or more channels, (iv) a liquid collector channel 4, and (v) a channel 5 with a slit. The boundary of the thermosyphon fin plate 8 is connected to the hot base plate to be cooled along its root and flows upward, while the thermosyphon acts as a condenser along the rest of the fin plate 8, transferring heat to the entire surface of the thermosyphon fin plate 8 and releasing the heat by convection with the air.

[0040] To make the thermosyphon fin plate 8, two thin plates are punched to produce matching embossings, each embossing having half of the cross section of the formed channel. When the two thin plates are placed together and brazed or welded together, they each have half of the above five components, forming a thermosyphon circuit inside the thermosyphon fin plate 8.

[0041] The channels of the evaporator / riser 1 are composed of one or more components, each of which has a constant width and depth, or increases in cross-sectional area by 1.5 to 3 times from the bottom to the top of the thermosyphon fin plate 8. The increase in size from bottom to top is achieved by gradually widening the cross-sectional area of ​​the channel from bottom to top, or by making the embossing deeper and deeper from bottom to top, or by a combination of both. The increase in cross-sectional area of ​​the channels of one or more evaporators / riser 1 helps stabilize the two-phase flow in the thermosyphon, thereby preventing backflow and reducing flow resistance, thereby increasing the circulation flow in the thermosyphon and in turn increasing the transferable heat. In one embodiment of the present invention, the transferable heat can be increased by 30% or more.

[0042] The channel of the evaporator / riser tube 1 is arranged at the edge of the root 6 of the thermosyphon fin plate 8 to absorb the heat transmitted from the electronic device along the edge of the root 6, thereby cooling on the cooling plate 9 and transporting the two-phase flow upward by evaporation of the coolant. The channel of the evaporator / riser tube 1 is sized so that almost all the incoming conductive heat is absorbed by the evaporating fluid in the channel of the evaporator / riser tube 1, and the heat is not forwardly conducted to the channel of the condenser / return tube 3. The cooling in the channel of the evaporator / riser tube 1 is heat from a continuous heat source at the edge of the root 6 of the thermosyphon fin plate 8, or heat from multiple heat sources distributed in the vertical direction along the edge of the root 6, or heat from a combination of heat sources.

[0043] The channels of the condenser / return pipe 3 are composed of a plurality of parallel channels to bring heat to the surface of the thermosyphon fin plate 8 and to be taken away by the external air flow. The plurality of channels reduces the flow resistance of the circulating fluid in the thermosyphon fin plate 8, wherein the number of channels used in the condenser / return pipe 3 is 5 times or more than that in the evaporator / rising pipe 1. Therefore, compared with the case where only one channel is used, the flow resistance of the condenser / return pipe 3 is reduced by more than 80%, which increases the heat dissipation capacity of the thermosyphon fin 8 by 30% or more.

[0044] like Figure 4 As shown, the gas-liquid distributor channel 2 is located at the top of the channel of the condenser / return pipe 3, which connects the top of the channel of the evaporator / riser pipe 1 with the top of the channel of the condenser / return pipe 3. The cross-sectional area of ​​the gas-liquid distributor channel 2 is 2 to 10 times the cross-sectional area of ​​the channel of the evaporator / riser pipe 1 and the channel of the condenser / return pipe 3 to reduce the flow resistance and ensure better distribution of the fluid to multiple condenser / return 3 channels.

[0045] The liquid collector channel 4 is located at the bottom of the condenser / return pipe 3, and is connected to the bottom end of the channel of the condenser / return pipe 3, and is connected to the channel of the evaporator / riser pipe 1 through a channel 5 with a slit. The cross-sectional area of ​​the liquid collector channel 4 is 2 to 10 times that of the channel of the evaporator / riser pipe 1 and the channel of the condenser / return pipe 3 to reduce the flow resistance thereof and ensure that the fluid flowing out of the channels of multiple condensers / return pipes 3 is well distributed.

[0046] like Figure 5 As shown, the channel 5 with slits is used to restrict the flow of the thermosyphon fluid, and the cross-sectional area of ​​the channel 5 with slits is 1 / 2 to 1 / 10 of the cross-sectional area of ​​the channel of the evaporator / riser pipe 1, and is located between the liquid collector channel 4 and the channel of the evaporator / riser pipe 1. The channel 5 with slits plays the role of throttling the liquid entering the channel of the evaporator / riser pipe 1 to promote stable flow, ensure the correct flow direction of the liquid, and prevent the vapor from flowing back from the evaporator / riser pipe 1 to the liquid collector channel 4. The size of its cross-sectional area depends on the choice of the working fluid, but it is always less than or equal to 50% of the cross-sectional area of ​​the evaporator / riser pipe 1.

[0047] The cross-sectional shapes of the evaporator / riser 1, condenser / return 3, gas-liquid distributor channel 2, liquid collector channel 4 and channel with slits 5 are circular, rectangular with curved corners or elliptical, depending on the stamping process. The channel of the evaporator / riser 1 and the channel in the condenser / return 3 have a depth of 0.5 mm-3 mm and a width of 0.5 mm-3 mm. The gas-liquid distributor channel 2 and the liquid collector channel 4 can be the same or different in size and have a depth range of 0.5 mm to 3 mm and a width range of 3 mm to 15 mm.

[0048] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art of the present invention, several equivalent substitutions or obvious variations can be made without departing from the concept of the present invention, and the performance or use is the same, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A thermosyphon fin plate, characterized in that: It includes two thin plates butted together and a thermosiphon formed between the two thin plates; The thermosyphon comprises: a channel of an evaporator / riser, a channel of a gas-liquid distributor, a channel of a liquid collector, a channel of a condenser / downcomer, and a channel with a slit; The channel of the evaporator / riser pipe is arranged at the edge of the root of the thermal syphon fin plate; the gas-liquid distributor channel is arranged at the top of the channel of the evaporator / riser pipe, and the top of the channel of the evaporator / riser pipe is connected to the top of the channel of the condenser / return pipe; the liquid collector channel is located at the bottom of the channel of the condenser / return pipe, and is connected to the channel of the evaporator / riser pipe through the channel with a slit; the channel of the evaporator / riser pipe and the channel in the condenser / return pipe have a depth of 0.5mm-3mm and a width of 0.5mm-3mm; the width, diameter or cross-sectional area of ​​the channel of the evaporator / riser pipe is uniform along its upward direction; or, the size of the cross-sectional area increases from the bottom to the top of the thermal syphon fin plate; the size of the cross-sectional area increases by 1.5-3 times from the bottom to the top of the thermal syphon fin plate.

2. The thermosyphon fin plate according to claim 1, characterized in that: The cross-sectional area of ​​the thermosiphon between the two thin plates is circular, rectangular with curved corners, or elliptical.

3. The thermosyphon fin plate according to claim 1, characterized in that: The depth and width of the gas-liquid distributor channel and the liquid collector channel are the same or different, with the depth ranging from 0.5 mm to 3 mm and the width ranging from 3 mm to 15 mm.

4. The thermosyphon fin plate according to claim 1, characterized in that: The evaporator / riser pipe has at least one channel, and the number of channels of the condenser / downcomer is at least 5 times the number of channels of the evaporator / riser pipe.

5. The thermosyphon fin plate according to claim 1, characterized in that: The cross-sectional area of ​​the channel with the slit is significantly smaller than the cross-sectional area of ​​the liquid collector channel and the channel of the evaporator / rising pipe.

6. The thermosyphon fin plate according to claim 1, characterized in that: The cross-sectional area of ​​the gas-liquid distributor channel is 2-10 times the cross-sectional area of ​​the channel of the evaporator / rising pipe or the channel of the condenser / reflux pipe; the cross-sectional area of ​​the liquid collector channel is 2-10 times the cross-sectional area of ​​the channel of the evaporator / rising pipe or the channel of the condenser / reflux pipe.

7. The thermosyphon fin plate according to claim 1, characterized in that: The cross-sectional area of ​​the channel with the slit is 1 / 2-1 / 10 of the cross-sectional area of ​​the evaporator / riser pipe channel.

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