Gradient minimum curved surface radiator manufactured through binder spraying additive manufacturing

Abstract

The utility model discloses a binder spraying additive manufacturing gradual change extremely-small curved surface radiator, and relates to the technical field of heat dissipation, the radiator comprises a heat conduction inner pipe and a gradual change extremely-small curved surface heat dissipation structure placed on the periphery of the heat conduction inner pipe, and the heat dissipation structure is in a hollow cylinder shape composed of extremely-small curved surface structure units; the heat conduction inner pipe and the heat dissipation structure are arranged inside and outside, and the heat dissipation structure is of an extremely small curved surface structure with radial linear gradient change, so that a smooth conduction path of heat in an internal micro-channel is effectively maintained, and the heat can be quickly and uniformly diffused to the periphery of the radiator.

Description

TECHNICAL FIELD

[0001] The utility model relates to additive manufacturing technical field and electronic device heat dissipation technical field especially, and it relates to a kind of binder jetting additive manufacturing gradual minimum curved surface radiator. BACKGROUND

[0002] Binder Jetting (BJ) additive manufacturing technology, also known as 3DP technology (three-dimensional printing), BJ additive manufacturing technology forms an STL file by slicing and layering a CAD three-dimensional model, a printing device spreads a layer of metal, ceramic, composite material, etc. powder on a metal printing platform through a powder falling device, and then a printing nozzle selectively deposits organic or inorganic binder on the powder layer according to the slicing profile of each layer of the three-dimensional model in the STL file to bond the powder together. As the printing process progresses, each layer of printed powder is bonded together to form a printed-green part with the desired geometric structure. The printed-green part is then subjected to curing, debinding, and sintering processes to ultimately obtain a formed part with ideal density and mechanical properties.

[0003] In today's high-performance computing, aerospace, national defense electronics, and other fields, the power density of electronic devices is constantly increasing, and the heat dissipation requirement per unit area has reached hundreds or even thousands of W / cm 2 . Traditional heat sinks such as copper pipes or heat dissipation pipes with fins have limited heat dissipation area and low air flow efficiency, resulting in low heat dissipation efficiency. To improve heat dissipation efficiency, it is often necessary to increase the number or volume of fins or the number or length of copper pipes, resulting in a large weight and volume of the heat sink. Traditional heat sinks have deficiencies in heat dissipation efficiency, weight, volume, material utilization, and other aspects. SUMMARY

[0004] Therefore, to solve the heat dissipation problem of small-volume high-heat electronic devices, the embodiments of the utility model provide a binder jetting additive manufacturing gradual minimum curved surface radiator, which has a large specific surface area and high heat dissipation efficiency.

[0005] The specific technical solutions adopted are as follows:

[0006] A binder jetting additive manufacturing gradual minimum curved surface radiator includes a heat-conducting inner tube and a heat dissipation structure placed around the heat-conducting inner tube. The heat dissipation structure is hollow and cylindrical. The heat dissipation structure is formed by an array of minimum curved surface structure units in the radial and height directions of the cylinder, and the minimum curved surface structure units are linearly graded in the radial direction. The gradual minimum curved surface radiator is formed by the fusion of the heat-conducting inner tube and the heat dissipation structure.

[0007] The function expression of the minimum curved surface structure unit is as follows:

[0008]

[0009] wherein r is a radial coordinate; theta is an angle of rotation about the cylindrical axis; z is an axial coordinate along the cylinder; L r (r) is a linear gradient function of the minimal surface structure unit gradient variation, increasing with increasing r; c is a horizontal control parameter.

[0010] Preferably, the linear gradient function of the minimal surface structure unit gradient variation is: L r (r) = L0·(1+alpha*r), wherein L0 is the minimal surface structure unit size at the center of the cylinder, and alpha is a coefficient controlling the size growth.

[0011] Preferably, the minimal surface structure unit size L0 at the center of the cylinder is between 1-10mm, and the coefficient alpha controlling the size growth is between 0.01-0.1.

[0012] Preferably, the horizontal control parameter c ranges from -1 to 1.

[0013] Preferably, the wall thickness of the minimal surface structure unit is between 0.5-5mm.

[0014] Preferably, the outer diameter of the heat-conducting inner tube is 0.2-0.5 times the diameter of the heat-dissipating structure, and the wall thickness of the heat-conducting inner tube is 0.1-0.5 times the outer diameter of the heat-conducting inner tube.

[0015] Preferably, the heat-dissipating structure is formed by additive manufacturing through binder jetting, and the printed powder comprises at least one of copper, silver, aluminum, magnesium, copper alloy, aluminum alloy, magnesium alloy, iron alloy, silicon carbide metal matrix composite, titanium carbide metal matrix composite, and titanium nitride metal matrix composite.

[0016] Preferably, the heat-dissipating structure and the heat-conducting inner tube are formed by integrated additive manufacturing through binder jetting.

[0017] The beneficial effects of the technical scheme provided by the embodiments of the utility model are:

[0018] The heat-conducting inner tube and the heat-dissipating structure adopt an inside-out arrangement, and the heat-dissipating structure adopts a minimal surface structure with a radial linear gradient variation, which effectively maintains a smooth conduction path for heat in the internal microchannels, thereby ensuring that heat can be more quickly and evenly spread to the surroundings of the heat sink.

[0019] In addition, the heat sink adopts an axisymmetric structure of a hollow cylinder, which effectively reduces the turbulent disturbance that may occur in the forced convection process, ensuring the stability of fluid flow, which further enhances the heat dissipation capacity of the high-temperature fluid in the heat-conducting inner tube. Attached Figure Description

[0020] Figure 1 This is a perspective view of a gradient minimal curved surface heat sink manufactured by adhesive spraying additive manufacturing according to this utility model;

[0021] Figure 2 This is a front view of a gradient minimal curved surface heat sink manufactured by adhesive spraying additive manufacturing according to this utility model;

[0022] Figure 3 This is a top view of a gradient minimal curved surface heat sink manufactured by adhesive spraying additive manufacturing according to this utility model;

[0023] Figure 4 It is a three-dimensional diagram of a minimal surface structural unit;

[0024] Figure 5 This is the front view of a minimal surface structural unit;

[0025] Figure 6 This is an internal structural diagram of a gradient minimal curved surface heat sink manufactured by adhesive spraying additive manufacturing according to this utility model;

[0026] Figure 7 Schematic diagram of Gyroid's uniformly porous heat sink;

[0027] Figure 8 A comparison curve of the surface temperature and heat dissipation efficiency of the heat-conducting inner tube under a flow state of 1 m / s between the Gradual-Gyroid gradient minimal curved surface heat sink and the Gyroid uniform porous heat sink.

[0028] In the diagram: 1. Heat dissipation structure; 2. Heat-conducting inner tube; 3. Minimal curved surface structural unit; 4. Wall; 5. Hole. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in detail below with reference to the accompanying drawings. The following describes a preferred embodiment among several feasible embodiments of this utility model, intended to help understand the basic concept of this utility model. It should be noted that all other embodiments that can be obtained by those skilled in the art based on the embodiments in this application without creative effort should be considered within the scope of protection claimed in this application.

[0030] In all the examples discussed herein, any specific values ​​are merely illustrative and not intended as limitations. Therefore, other examples of the exemplary embodiments may have different values.

[0031] Although not discussed in detail, techniques, methods, and apparatuses known to those of ordinary skill in the art of binder jet additive manufacturing should be considered as part of the specification.

[0032] Referring to Figure 1 , 2 and 3, the embodiment of the present application provides a binder jet additive manufacturing gradual minimum curved surface radiator, comprising a heat-conducting inner tube 2 and a heat dissipation structure 1 placed outside the heat-conducting inner tube 2.

[0033] The heat-conducting inner tube 2 is in the shape of a pipe with a certain wall thickness, which is used to directly contact with the fluid to be cooled and plays a role of heat conduction. It should be pointed out that at least one end port of the heat-conducting inner tube 2 can be provided in other shapes according to the shape of the device to be cooled, and at least one arbitrary port can be connected to the device to be cooled through a high-temperature-resistant rubber gasket.

[0034] In electronic devices, the radiator described in the present application can replace the existing heat-conducting copper pipe, thereby showing excellent heat dissipation performance.

[0035] In combination with Figure 4 and 5 , the heat dissipation structure 1 is a three-period minimum curved surface structure formed by arraying the minimum curved surface structure units 3 in the radial and height directions, and the minimum curved surface structure units 3 change linearly along the radial direction. The wall surface 4 of each minimum curved surface structure unit 3 of the heat dissipation structure 1 is a spiral curved surface, which increases the heat transfer surface area, and the holes formed between each minimum curved surface structure unit 3 of the heat dissipation structure 1 form a smooth and tortuous heat flow path, so that heat can be dissipated more quickly by the heat dissipation structure 1, thereby improving the heat dissipation efficiency.

[0036] The minimum curved surface structure units 3 in the heat dissipation structure 1 change linearly along the radial direction, and the porosity of the heat dissipation structure 1 gradually increases along the radial direction, so that the heat dissipation structure 1 has a larger heat dissipation area near the center of the device to be cooled at high temperature, which is beneficial to the rapid dissipation of heat at the axis of the heat dissipation structure 1 to the surrounding. Compared with the uniform minimum curved surface structure, it has lower surface temperature and higher heat dissipation coefficient under the same heat dissipation condition, so the heat dissipation structure 1 has better heat dissipation performance.

[0037] As shown in 4 and 5, in the present embodiment, the minimum curved surface structure unit 3 selects a Gyroid curved surface, and the corresponding function expression is as follows:

[0038]

[0039] Where r is the radial coordinate; θ is the angle of rotation around the cylindrical axis; z is the axial coordinate along the cylinder; L r(r) is a size function that controls the change in the size of the minimal surface structural unit, which increases as r increases; c is a horizontal control parameter, with a range of -1. <c<1。L r (r) represents the linear gradient function of the gradient change of the minimal surface structural unit.

[0040] The linear gradient function L of the gradient change of the minimal surface structural unit r (r) = L0·(1+αr), where L0 is the size of the minimum surface structure unit at the center, that is, the size of the minimum surface structure unit when r = 0, and α is the coefficient that controls the size growth.

[0041] The size of the structural unit 3 at the axial position is adjusted by adjusting the minimum curved surface structural unit size L0 at the center, the radius and height of the heat dissipation structure 1 are adjusted by adjusting the radial coordinate r and the axial coordinate z, and the growth rate of the structural unit 3 in the radial direction is adjusted by adjusting the size growth coefficient α.

[0042] In this embodiment, the minimum curved surface structural unit size L0 at the center of the cylinder of heat dissipation structure 1 is 5mm, and the maximum radius r of the cylinder of heat dissipation structure 1 is... max The diameter is 20mm, and the size of the minimal curved surface structure unit at the edge of the cylindrical heat dissipation structure 1 is twice that at the center, i.e., L r (r max )=L0·(1+αr max Substituting α = 2L0 into the boundary conditions, we can see that the size growth coefficient α is equal to 0.05.

[0043] The size growth factor α can be adjusted according to the actual size of the heat dissipation structure 1 and the radial gradient rate.

[0044] The shape of the heat dissipation structure 1 is designed according to the size of the device to be heated. For example, in this embodiment, the shape of the heat dissipation structure 1 is set as a cylinder with r (20mm) × z (50mm). The wall thickness of the minimal curved surface structure unit 3 is 1.2mm, L0 is 5mm, α is 0.05, and the outer diameter of the heat-conducting inner tube 2 is 16mm, with a wall thickness of 2mm.

[0045] In this embodiment, the heat dissipation structure 1 is formed by adhesive jet printing. The printed powder is pure copper powder material, and then it is prepared by integrated adhesive jet additive manufacturing, curing, degreasing and sintering.

[0046] In other embodiments, the material of the heat dissipation structure can also be other existing metals, metal alloys or metal matrix composites. The other existing metals, metal alloys include, but are not limited to, at least one of silver, aluminum, magnesium, copper alloy, aluminum alloy, stainless steel, high-temperature alloy, magnesium alloy or iron alloy. The other existing metal matrix composites include at least one of silicon carbide reinforced aluminum matrix composite, titanium carbide reinforced aluminum alloy, titanium nitride reinforced aluminum alloy or titanium carbide reinforced iron alloy. The metal matrix composite can be prepared by ball milling the corresponding ceramic powder and metal powder.

[0047] The heat dissipation structure and the heat conduction inner tube described in the present application can be integrally formed by adhesive jet printing, and then subjected to post-processing such as curing, debinding and sintering.

[0048] As shown in FIG. 1, it is a Gyroid uniform porous heat sink composed of standard Gyroid minimal surface structure units; as shown in FIG. 2, it is a Gradual-Gyroid gradual minimal surface heat sink. Figure 7 Figure 8 The comparison curve diagram of the surface temperature and the heat dissipation efficiency of the heat conduction inner tube of the Gradual-Gyroid gradual minimal surface heat sink and the Gyroid uniform porous heat sink at a flow rate of 1 m / s is shown in FIG. 3.

[0049] It can be seen from the test data that under the same heat dissipation condition, the surface temperature of the Gradual-Gyroid gradual minimal surface heat sink is lower than that of the Gyroid uniform porous heat dissipation structure, and the heat dissipation coefficient is obviously increased. It can be seen that the maximum value of the heat dissipation coefficient of the Gyroid uniform porous heat dissipation structure is 353 W / (m·K), and the maximum value of the heat dissipation coefficient of the Gradual-Gyroid gradual minimal surface heat sink is 365 W / (m·K). At the same time, compared with the Gyroid heat dissipation structure, the decline rate of the heat dissipation coefficient of the Gradual-Gyroid heat dissipation structure is lower with the increase of the inlet fluid temperature, which proves that the performance of the Gradual-Gyroid gradual minimal surface heat sink manufactured by the adhesive jet additive manufacturing is obviously improved compared with the uniform porous heat sink.

[0050] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the present application, and all should be covered in the scope of the claims of the present application.​

Claims

1. A binder jet additive manufactured graded minimal surface heat spreader, characterized in that, The application relates to a heat dissipation structure and a heat dissipation method. The heat dissipation structure comprises a heat-conducting inner tube and a heat dissipation structure arranged outside the heat-conducting inner tube, the heat dissipation structure is in a hollow cylindrical shape, the heat dissipation structure is formed by arraying small curved surface structure units in the radial direction and the height direction of the cylinder, and the small curved surface structure units are linearly graded in the radial direction. The function expression of the small curved surface structure unit is as follows: z = L0 * (1 - alpha) * (1 - c * r) * r + L0 * alpha * r. where r is the radial coordinate; θ is the angle of rotation about the cylindrical axis; z is the axial coordinate along the cylinder; L r (r) is a linear gradient function of the gradient variation of the minimal surface structure unit, increasing with increasing r; c is a horizontal control parameter.

2. The binder jet additive manufactured graded minimal surface heat spreader of claim 1, wherein, The linear gradient function of the gradient variation of the minimal surface structure unit is: L r (r) = L0·(1 + ar), wherein L0is the size of the minimal surface structure unit at the center of the cylinder, and a is a coefficient controlling the size growth.

3. The binder jet additive manufactured graded minimal surface heat spreader of claim 2, wherein, The size L0 of the small curved surface structure unit at the center of the cylinder is between 1 and 10 mm, and the coefficient alpha for controlling the size growth is between 0.01 and 0.

1.

4. The binder jet additive manufactured graded minimal surface heat spreader of claim 1, wherein, The range of the horizontal control parameter c is -1 < c < 1.

5. The binder jet additive manufactured graded minimal surface heat spreader of claim 1, wherein, The wall thickness of the small curved surface structure unit is between 0.5 and 5 mm.

6. The binder jet additive manufactured graded minimal surface heat spreader of claim 1, wherein, The outer diameter of the heat-conducting inner tube is 0.2-0.5 times the diameter of the heat dissipation structure, and the wall thickness of the heat-conducting inner tube is 0.1-0.5 times the outer diameter of the heat-conducting inner tube.

7. The binder jet additive manufactured graded minimal surface heat spreader of claim 1, wherein, The heat dissipation structure is formed by additive manufacturing through adhesive spraying, and the printed powder comprises at least one of copper, silver, aluminum, magnesium, copper alloy, aluminum alloy, magnesium alloy, iron alloy, silicon carbide metal matrix composite material, titanium carbide metal matrix composite material and titanium nitride metal matrix composite material.

8. The binder jet additive manufactured graded minimal surface heat spreader of claim 1, wherein, The heat dissipation structure and the heat-conducting inner tube are integrally formed by additive manufacturing through adhesive spraying.

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