Flat plate pulsating heat pipe, application and processing method thereof

Abstract

This invention discloses a flat plate-type pulsating heat pipe, comprising a straight flat tube and two end plates. The straight flat tube has parallel channels inside, numbering between 4 and 50 (an even number). The end plates are located at both ends of the straight flat tube, connecting the internal channels into a single flow channel. One end plate has a process hole with a sealing structure at the process hole. The hydraulic diameter of the internal channels of the straight flat tube is 0.3~4mm. The walls of the internal channels of the straight flat tube are grooved from the ends inwards, with a groove depth not exceeding 20mm. The end plate with a process hole and the flat tube are joined at a distance of less than 1 mm. The end plate is hollow inside the flat tube and inserted into the flat tube. The hydraulic diameter of the internal channel of the flat tube is 0.3~4 mm. The flat tube design allows the end plate to be made into the heat collection end of a flat pulsating heat pipe as needed. Different thicknesses of end plates are used according to the heat output. The end plate is in full contact with the outer surface of the flat tube to reduce contact thermal resistance and better utilize the advantages of the pulsating heat pipe.

Description

Technical Field

[0001] This invention relates to the field of heat exchange application technology, and in particular to a flat plate pulsating heat pipe, its application, and a method for processing the flat plate pulsating heat pipe. Background Technology

[0002] In transportation, aerospace, and industrial production processes, it is often necessary to heat or cool equipment systems or working media. Pulsating heat pipes, also known as oscillating heat pipes or self-excited oscillating heat pipes, were first proposed by scholar Akachi in 1990 and have been around for over twenty years. Their potential for high heat transfer efficiency and low manufacturing cost have made them a current research hotspot.

[0003] Patent CN203148276U describes a parallel-flow pulsating heat pipe with a serpentine arrangement. Patent CN203215636 proposes adding fins between the parallel-flow pulsating heat pipes to enhance heat dissipation. Patent CN112964104A proposes a heat pipe heat exchanger, also with a serpentine arrangement. Compared to traditional parallel-flow heat exchangers, serpentine pulsating heat pipes often require longer flat tubes during manufacturing, especially in large radiator applications. For example, a two-meter-long serpentine pulsating heat pipe can have a single pulsating tube length reaching 80 meters or even hundreds of meters. This results in high system operating resistance, often preventing the formation of a large circulation loop and instead causing oscillating operation between hot and cold zones, thus reducing the heat dissipation effect of the pulsating heat pipe. Furthermore, the above patents lack clarity in how to connect the internal tubes of the parallel pipes to form a single flow channel, making implementation difficult and hindering the large-scale market application of parallel-flow pulsating heat pipes.

[0004] Meanwhile, when used as a radiator, the end face of the serpentine pulsating heat pipe is curved, and fins cannot be added inside the arc to enhance heat transfer. Moreover, the arc is not easy to make close contact with the heat-generating element at the end face. Although the pulsating heat pipe has strong heat transfer energy, the contact thermal resistance at the end face greatly affects its performance. Summary of the Invention

[0005] The main technical problem solved by this invention is to provide a flat plate-type pulsating heat pipe, comprising a straight flat tube and two end plates. The straight flat tube has parallel channels inside, with a number of 4 to 50 channels, which are always even. The end plates are located at both ends of the straight flat tube, connecting the internal channels of the straight flat tube into a single flow channel. One end plate has a process hole for evacuating vacuum and injecting heat pipe working fluid. The process hole is sealed after the working fluid is filled. The hydraulic diameter of the internal channels of the straight flat tube is 0.3 to 4 mm. The walls of the internal channels of the straight flat tube are grooved from the ends inward, with a groove depth not exceeding 20 mm and not less than 1 mm. The two ends are grooved at intervals. The end plate with the process hole has an internally hollow structure at the joint with the straight flat tube, and is inserted into the straight flat tube with an insertion distance of not less than 1 mm.

[0006] Preferably, the end plate for the process hole is a single part, including a recessed plane. The recessed plane is used to connect with the end face of the straight flat tube. The recessed plane is at least 3 mm away from the opening surface of the end plate. There are two hollow protrusions on this recessed surface. The distance from the protrusions to their roots is more than 1 mm. The outer edges of these two protrusions are inserted into the channel of the straight flat tube. The internal pipes of these two protrusions are connected inside the end plate and open to the outside of the end plate.

[0007] Preferably, the end plate for the process hole is an assembly, comprising an assembly body and three process tubes. The assembly body includes a recessed plane for connecting to the end face of a flat tube. The recessed plane is at least 3mm away from the opening surface of the end plate. Two process holes are formed on this recessed surface. Two process tubes are placed between these two process holes and fixed by welding or bonding. When the two process tubes are assembled, they should be higher than the recessed surface of the assembly body, with a height difference of more than 2mm. These two process tubes are connected to a third process tube outside the assembly body for vacuuming and adding heat pipe working fluid during the fabrication of the flat pulsating heat pipe.

[0008] Preferably, the end plate without process holes is a single part, including a recessed plane. The recessed plane is at least 3mm away from the opening surface of the end plate. The distance of the recessed plane can be adjusted according to the heat of the heat source, but not more than 50mm. The recessed plane is used to connect with the end face of the flat tube, and the surrounding surface of the recessed plane is used to connect with the outer wall of the flat tube.

[0009] Preferably, the end plate and the straight flat tube can be connected by brazing or by fixing with weather-resistant colloid.

[0010] Preferably, the cross-section of the straight flat tube flow channel is circular, elliptical, square with rounded corners, or other polygonal.

[0011] Preferably, the internal filling working medium is one or a mixture of pure water, ammonia, methanol, ethanol, ethers, Freon such as R134a, R410a, and R22, fluorinated liquid, and acetone.

[0012] Furthermore, by attaching a portion of the large surface of the flat plate pulsating heat pipe to the heating surface and another portion of the large surface of the flat plate pulsating heat pipe to the heat dissipation surface, heat transfer can be achieved. Multiple flat plate pulsating heat pipes can be arranged side by side in the large surface direction to achieve greater heat transfer.

[0013] Furthermore, the flat plate pulsating heat pipes are arranged side by side in the vertical direction of the plane of the straight flat tubes, and fins are set between the planes of each straight flat tube to form a flat plate heat exchanger.

[0014] Furthermore, the flat-plate pulsating heat pipes are arranged side by side in the vertical direction of the plane of the straight flat tubes, and a heat collection plate is installed between the planes of each straight flat tube at one end of the parallel channel direction. Fins are set between the planes of each straight flat tube at the other end of the parallel channel to form a radiator that dissipates the heat collection plate into the air.

[0015] Preferably, the heat collection plate is manufactured by extrusion molding, and the distance between the inner wall surface of the perforated extrusion and the contact surface of the flat pulsating heat pipe is less than 1 mm.

[0016] A method for manufacturing a flat-plate pulsating heat pipe involves first taking a straight, flat tube with no fewer than 4 and no more than 50 internal channels, which are relatively parallel to each other. The hydraulic diameter of the internal channels is 0.3~4mm. Grooves are cut into the walls of the internal channels from the end inwards, with a groove depth not exceeding 50mm and not less than 3mm. Grooves are also cut at intervals at both ends. After grooving, one end of the straight, flat tube is sealed by crimping, welding, or gluing. Then, a vacuum operation is performed on the other end of the straight, flat tube. After vacuuming, the heat pipe working fluid is filled, with the filling amount being 20%~80% of the heat pipe's internal volume by liquid working fluid mass. After filling with the heat pipe working fluid, the other end is sealed by crimping, welding, or gluing. The pulsating heat pipe manufactured by this method does not form circulation and is an oscillating pulsating heat pipe.

[0017] The beneficial effects of this invention are:

[0018] 1. Adopting a straight flat tube design, the end plate can be directly made into the heat collection end of the flat pulsating heat pipe as needed. Different thicknesses of end plates are used according to different heat outputs. The end plate is in full contact with the outer surface of the straight flat tube, reducing contact thermal resistance and better leveraging the advantages of the pulsating heat pipe.

[0019] 2. By using multiple flat-plate pulsating heat pipes in parallel, the process is standardized while meeting the requirements of large heat dissipation, ensuring manufacturing efficiency and improving product quality.

[0020] 3. By improving the design of the hollow boss inside the process port end plate, the solder and adhesive will not flow into the process hole and cause blockage when brazing or colloid curing is used, thus improving the manufacturability of the product.

[0021] 4. By adding heat collection plates, the heat collection capacity of the flat-plate pulsating heat pipe can be further improved, giving full play to its efficient heat dissipation effect. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a flat plate type pulsating heat pipe according to the present invention;

[0023] Figure 2 This is a schematic diagram of the internal structure of a flat plate-type pulsating heat pipe according to the present invention;

[0024] Figure 3 This is a schematic diagram of the assembly of the process interface end plate and the straight flat tube of the present invention;

[0025] Figure 4 This is a schematic diagram of a single component of the present invention, the end plate with process interface.

[0026] Figure 5 This is a schematic diagram of the assembly of the component with the process interface end plate of the present invention;

[0027] Figure 6 yes Figure 5 An enlarged view of the upper part;

[0028] Figure 7 This is a schematic diagram of a heat exchanger composed of multiple flat plate-type pulsating heat pipes according to the present invention.

[0029] Figure 8 This is a three-dimensional schematic diagram of a heat exchanger composed of multiple flat plate-type pulsating heat pipes according to the present invention.

[0030] Figure 9 This is a schematic diagram of the heat sink of the present invention, which combines a heat collection plate and multiple flat pulsating heat pipes. Detailed Implementation

[0031] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0032] It includes a straight flat tube and two end plates. The straight flat tube has 4 to 50 parallel channels inside, which are always an even number. The end plates are located at both ends of the straight flat tube and connect the internal channels of the straight flat tube to form a single flow channel.

[0033] Please see Figure 1 and Figure 2A flat plate type pulsating heat pipe includes: a straight flat tube 1, an upper end plate 2, and a lower end plate 3. The straight flat tube 1 is made by aluminum extrusion. The upper end plate 2 and the lower end plate 3 are located at both ends of the straight flat tube 1, connecting the internal pipes of the straight flat tube 1 in series to form a single flow channel. The straight flat tube 1 contains 14 rectangular flow channels. The wall thickness between the flow channels of the straight flat tube 1 is 0.5 mm. On one side of the upper end plate 2, the 2nd, 4th, 6th, and 8th flow channels of the straight flat tube 1 are... The walls of the flat tube 1, 10, and 12 are grooved to a depth of 3mm from the end face. On one side of the lower end plate 3, the walls of the flat tube 1, 1, 3, 5, 7, 9, 11, and 13 are grooved to a depth of 3mm from the other end face. A process hole is opened on the upper end plate 2, through which a process tube 4 is connected. The tube is evacuated through the process tube 4, and after the vacuum is completed, it is filled with R134a working fluid, the liquid volume of which accounts for 50% of the internal volume of the pulsating heat pipe. After filling, the process tube 4 is sealed. The flat tube 1, upper end plate 2, lower end plate 3, and process tube 4 are all made of aluminum and are connected together by vacuum brazing with aluminum solder.

[0034] Figure 3 and Figure 4 The upper end plate 2 (single part type) is connected to the straight flat tube 1. The upper end plate 2 includes a recessed plane 21, which is connected to the end face of the straight flat tube 1. The recessed plane 21 is 4mm away from the opening surface of the end plate. There are two hollow protrusions on this recessed surface, which are internal hollow structure one 22 and internal hollow structure two 23. The distance to the root is more than 5mm. This distance is beneficial for mechanical structure welding and other operations. The outer edges of these two protrusions are inserted into the channel of the straight flat tube 1. The internal pipes of these two protrusions are connected together inside the upper end plate 2 by connecting manifold 24 and open to the outside of the upper end plate 2.

[0035] Figure 5 For another connection between the upper end plate 2 (module type) and the straight flat tube 1, the upper end plate 2 consists of the main body and three process tubes: process tube 1 (5), process tube 2 (6), and process tube 3 (7). The module body includes a recessed plane for connecting to the end face of the straight flat tube. The recessed plane is 4mm below the opening surface of the end plate. Two process holes are formed on this recessed surface, and process tubes 1 (5) and 2 (6) are placed between these two process holes and fixed by brazing. When assembling, the two process tubes should be 5mm higher than the recessed surface of the module body. Process tubes 1 (5) and 2 (6) connect to process tube 3 (7) outside the module body. Here, process tube 3 (7) is a T-junction. See the reference for details. Figure 6 It is used for vacuuming and filling the heat pipe working fluid during the fabrication of flat-plate pulsating heat pipes.

[0036] Figure 7 and Figure 8A heat exchanger composed of flat plate pulsating heat pipes is described. Ten flat plate pulsating heat pipes are arranged side by side in a vertical direction along the plane of the straight flat tubes, and fins 8 are set between the planes of each straight flat tube to form a flat plate heat exchanger. Hot air can be introduced into one end of the flat plate heat exchanger as needed, and cold air can be introduced into the other end of the flat plate heat exchanger to achieve heat exchange between hot and cold air. Different area ratios can be allocated according to the heat exchange requirements. For the end with strict temperature change requirements, the area allocation ratio of the heat exchanger can be increased to reduce air flow resistance and reduce the temperature difference of air flow.

[0037] Figure 9 A radiator combining a heat collection plate and multiple flat pulsating heat pipes is described. Ten flat pulsating heat pipes are arranged side by side in a direction perpendicular to the plane of the straight flat tubes. A heat collection plate 9 is installed between the planes of each straight flat tube at one end of the parallel channel direction. Fins 8 are set between the planes of each straight flat tube at the other end of the parallel channel to form a radiator that dissipates heat from the heat collection plate into the air. The heat collection plate 9 is manufactured by extrusion molding process, and the distance between the inner wall surface of the extruded section and the outer surface of the flat pulsating heat pipe is 0.5 mm.

[0038] Furthermore, in this embodiment, the upper end plate 2 and lower end plate 3 of the flat plate-type pulsating heat pipe can achieve the function of a heat collection plate by increasing the contact area with the straight flat tube 1. Figure 7 The examples described are merely an extension of the application, providing businesses with more options, and are not intended to limit this functionality.

[0039] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A flat-plate pulsating heat pipe, characterized in that, The device includes a straight flat tube and two end plates. The straight flat tube has 4 to 50 parallel channels inside, which are always an even number. The end plates are located at both ends of the straight flat tube and connect the internal channels to form a single flow channel. One end plate has a process hole with a sealing structure at the process hole. The hydraulic diameter of the internal channels of the straight flat tube is 0.3 to 4 mm. The walls of the internal channels of the straight flat tube are grooved from the port inward, with a groove depth not exceeding 20 mm and not less than 1 mm. The two ends are grooved at intervals. The end plate with the process hole has a hollow structure at the joint with the straight flat tube and is inserted into the straight flat tube with an insertion distance of not less than 1 mm. The end plate with process holes is a single part, including a recessed plane. The recessed plane is used to connect with the end face of the straight flat tube. The recessed plane is not less than 3mm away from the opening surface of the end plate. There are two hollow protrusions on this recessed surface. The distance from the protrusion to the root is more than 1mm. The outer edges of these two protrusions are inserted into the channel of the straight flat tube. The internal pipes of these two protrusions are connected inside the end plate and open to the outside of the end plate. Alternatively, an end plate with process holes can be considered as a component, comprising a component body and three process tubes. The component body includes a recessed plane for connecting to the end face of a flat tube. The recessed plane is at least 3mm away from the opening surface of the end plate. Two process holes are opened on this recessed surface, and two process tubes are placed between these two process holes and fixed by welding or bonding. When assembling, the two process tubes should be higher than the recessed surface of the component body, with a height difference of more than 2mm. These two process tubes are connected to the third process tube outside the component body for vacuuming and filling the heat pipe working fluid during the fabrication of the flat pulsating heat pipe.

2. The flat-plate pulsating heat pipe according to claim 1, characterized in that: The end plate without process holes is a single part containing a recessed plane. The recessed plane is at least 3mm away from the opening surface of the end plate. The distance of the recessed plane is adjusted according to the heat of the heat source, but not more than 50mm. The recessed plane is used to connect with the end face of the straight flat tube, and the surrounding surface of the recessed plane is used to connect with the outer wall of the straight flat tube.

3. The flat-plate pulsating heat pipe according to claim 1, characterized in that: The end plates and straight flat tubes are connected by brazing or by using weather-resistant colloid for fixing.

4. The flat-plate pulsating heat pipe according to any one of claims 1-3, characterized in that: A portion of the large surface of the flat-plate pulsating heat pipe is attached to the heating surface, and another portion of the large surface of the flat-plate pulsating heat pipe is attached to the heat dissipation surface.

5. A flat-plate heat exchanger, characterized in that: Any one of the flat plate type pulsating heat pipes according to claims 1-3 is arranged side by side in the vertical direction of the plane of the flat tubes, and fins are provided between the planes of each flat tube.

6. A flat-plate pulsating heat pipe radiator, characterized in that: Any one of the flat plate type pulsating heat pipes according to claims 1-3 is arranged side by side in the vertical direction of the plane of the flat tubes, and a heat collection plate is installed between the planes of each flat tube at one end of the parallel channel direction, and fins are arranged between the planes of each flat tube at the other end of the parallel channel.

7. The flat-plate pulsating heat pipe radiator according to claim 6, characterized in that: The heat collection plate is manufactured by extrusion molding, and the distance between the extruded inner wall surface and the contact surface of the flat pulsating heat pipe is less than 1 mm.

8. A method for processing a flat-plate pulsating heat pipe as described in claim 1, characterized in that: First, take a straight, flat tube with no fewer than 4 and no more than 50 internal channels, which are relatively parallel to each other. The hydraulic diameter of the internal channels of the straight, flat tube is 0.3~4mm. Groove the inner wall of the channels from the end to the inside of the straight, flat tube. The groove depth should not exceed 50mm and should not be less than 3mm. Grooves should be made at intervals at both ends. After grooving, seal one end of the straight, flat tube by crimping, welding or gluing. Then, perform a vacuum operation on the other end of the straight, flat tube. After vacuuming, fill the heat pipe with heat pipe working fluid. The amount of heat pipe working fluid should be 20%~80% of the internal volume of the heat pipe by the mass of liquid working fluid. After filling the heat pipe with heat pipe working fluid, seal the other end by crimping, welding or gluing.

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