CN114745925B - A micro-groove group heat dissipation device with porous medium material and a heat dissipation method - Google Patents

Abstract

The present invention provides a microgroove group heat dissipation device with porous medium material and a heat dissipation method. The device comprises: a main body heat sink, a vacuum cavity is arranged inside the main body heat sink, and a phase change medium is filled in the vacuum cavity; a fin group is arranged outside the main body heat sink, including a fin heat sink; a microgroove group heat sink is arranged at the bottom of the main body heat sink and connected to the bottom of the vacuum cavity; a porous medium material is fixedly arranged between the microgroove group heat sink and the main body heat sink, the phase change medium is kept in contact with the microgrooves on the microgroove group heat sink through the porous medium material, and the phase change medium is kept in contact with the microgrooves on the microgroove group heat sink through the arrangement of the porous medium material. Under a certain liquid filling rate, the phase change medium can adapt to tilting and rotating angles in any direction, thereby solving the problem that the microgroove group heat sink in the current traditional bottom-emitting LED microgroove group heat sink cannot contact the liquid replenishment of the phase change medium in the heat sink under certain tilting and rotating angles.

Description

A micro-groove group heat dissipation device with porous medium material and a heat dissipation method

Technical Field

The invention belongs to the technical field of heat dissipation and cooling, and in particular relates to a micro-groove group heat dissipation device with porous medium material and a heat dissipation method.

Background technique

Microscale heat transfer technology is the forefront and hotspot in the current international academic research field of heat transfer. Phase change cooling technology for microelectronic and optoelectronic devices, micro heat pipe technology and micro groove group evaporative heat sink technology are micro cooling system technologies that are different from existing cooling technologies. Among them, the micro groove group evaporative heat sink structure can use capillary force to make the liquid flow along the micro groove while forming a thin liquid film with high evaporation capacity in the extended meniscus area near the solid-liquid-gas three-phase contact line. At present, the development of this technology is not seriously affected by the critical heat flow restriction, so the application prospects and economic benefits in many engineering and technical fields are very promising.

Porous media materials include metal porous materials and non-metal porous materials. Metal porous materials are widely used in the field of basic heat transfer due to their advantages such as light weight, large specific surface area, good thermal conductivity, and controllable porosity. Foam metal is a new type of ultra-light multifunctional metal porous material containing foam pores, which has the advantages of controllable porosity, stable structure, and high temperature resistance. Relevant studies have shown that the application of foam metal in flow boiling phase change heat transfer can greatly improve the nucleation rate of nucleate boiling, increase fluid disturbance, and increase the heat exchange area, thereby greatly improving the heat exchange efficiency. Non-metallic porous materials include ceramic porous materials, carbon foam porous materials, etc. Porous non-metallic materials have the advantages of low price, long service life, light weight, and anti-oxidation.

The current traditional bottom-emitting LED micro-groove group heat sink will have a certain tilt and rotation angle according to actual needs during normal operation. Since the micro-groove group heat sink channels are directional, the channels will not be able to contact the phase change medium at certain tilt and rotation angles. If the micro-groove group heat sink does not receive enough phase change medium, the heat sink will dry out locally, causing the LED light source to burn out. The existing solution is to increase the liquid filling rate to increase the chances of the micro-groove group heat sink channels contacting the phase change medium, but a higher liquid filling rate will increase the heat transfer thermal resistance and affect the working performance of the heat sink.

Summary of the invention

Purpose: In order to overcome the deficiencies in the prior art, the present invention provides a method of using porous medium materials to solve the problem that the microgroove group heat sink in the current traditional bottom-emitting LED microgroove group heat sink cannot contact the liquid replenishment problem of the phase change working fluid in the heat sink under certain tilt and rotation angles, so as to improve the adaptability of the microgroove group heat sink to tilt and rotation angles in practical applications.

Technical solution: To achieve the above purpose, on the one hand, a micro-groove group heat dissipation device with porous medium material is provided, comprising:

The main heat sink has a vacuum cavity inside which is filled with a phase-change medium;

A fin group, which is arranged outside the main body radiator, includes a fin radiator;

A micro-groove group heat sink is arranged at the bottom of the main radiator and connected to the bottom of the vacuum cavity;

The porous medium material is fixedly arranged between the micro-groove group heat sink and the main radiator, and the phase change working medium keeps in contact with the micro-grooves on the micro-groove group heat sink through the porous medium material.

As a preferred embodiment of the present invention: the porous medium material is ceramic or foam metal.

As a preferred embodiment of the present invention: the microgroove group heat sink is a concentric cylinder of different diameters, and the radius of the upper cylinder is smaller than the radius of the lower cylinder; the porous medium material is a torus, and the inner diameter is the same as the radius of the upper cylinder of the microgroove group heat sink, the outer diameter is the same as the radius of the lower cylinder of the microgroove group heat sink, and the height is the same as the height of the upper cylinder of the microgroove group heat sink.

As a preferred embodiment of the present invention: the upper surface of the upper cylinder of the microgroove group heat sink has uniformly distributed microgrooves, and the cross section of the microgroove is one of a rectangle, a triangle, and a trapezoid.

As a preferred embodiment of the present invention: the main radiator is a sunflower radiator.

As a preferred embodiment of the present invention: the fin heat sink in the fin group includes 4 thick fins and N thin fins, N is greater than or equal to 16, the 4 thick fins are respectively centrally symmetrical and perpendicular to each other, and the periphery of the radiator is divided into 4 areas in equal proportion, the thin fins are evenly distributed in these four areas, and the number of thin fins in each area is the same.

As a preferred implementation manner of the present invention: the main radiator and the fin group are integrally formed, or the fin group is connected to the main radiator.

As a preferred embodiment of the present invention: the phase change working fluid comprises: at least one of distilled water, electronic fluoride liquid, deionized water, ethanol, methanol, and liquid metal.

On the other hand, a heat dissipation method using the microgroove group heat dissipation device with porous medium material is provided, wherein the heat generated by the heat source is transferred to the bottom surface of the microgroove group heat sink by heat conduction through thermal grease or thermal silica gel, and due to the presence of the porous medium material, under certain tilt and rotation angles, the phase change medium in the main radiator contacts the microgroove group heat sink through the porous medium material, and the phase change medium enters the microgroove for heat exchange under the drive of the capillary force of the microgroove; after the phase change medium liquid absorbs heat and evaporates into medium vapor, it condenses on the inner wall surface of the main radiator, and transfers the heat to the side wall of the main radiator, and the heat is transferred to the fin group by heat conduction through the side wall of the main radiator, and finally the fin group and the external environment dissipate the heat to the external environment by natural convection heat transfer.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention uses a micro-groove group heat sink with porous medium material and a heat dissipation method thereof. The porous medium material is selected from ceramic porous material or foam metal. The tilt and rotation angle of the radiator can be adjusted according to needs. Under a certain liquid filling rate, it can adapt to a tilt angle range of -90~90° and a rotation angle in any direction, ensuring that the micro-groove group heat sink and the phase change working medium are in continuous contact, and the micro-groove group heat sink will not be locally dry-burned.

(2) By using porous medium materials to allow the phase change fluid to enter the micro-groove group heat sink from the edge of the groove, the phase change fluid can be more evenly contacted with the micro-groove group heat sink for heat dissipation at a moderate filling rate, thereby preventing the filling rate from being increased in order to increase the chance of the micro-groove group heat sink groove contacting the phase change fluid, thereby increasing the heat transfer thermal resistance and affecting the working performance of the radiator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is an overall schematic diagram of a microgroove group heat dissipation device having a porous medium material provided in this embodiment;

FIG2 is a schematic diagram of a porous medium material provided in this embodiment;

FIG3 is a schematic diagram of a microgroove group heat sink provided in this embodiment;

FIG4 is a cross-sectional view of a microgroove group heat dissipation device having a porous medium material provided in this embodiment;

FIG. 5 is a partial schematic diagram provided in this embodiment.

In the figure, 1 is the main heat sink; 2 is the fin group; 3 is the porous medium material; 4 is the micro-groove group heat sink; and 5 is the vacuum cavity.

Detailed ways

The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

The present invention provides a micro-groove group heat sink with a porous medium material 3, comprising: a main heat sink 1, a fin group 2 porous medium material 3, and a micro-groove group heat sink 4. The main heat sink 1 is provided with a vacuum cavity 5 inside, and the vacuum cavity 5 is filled with a phase change medium. The fin group 2 is arranged outside the main heat sink 1. The micro-groove group heat sink 4 is arranged at the bottom of the main heat sink 1 and connected to the bottom of the vacuum cavity 5. The porous medium material 3 is ceramic or foam metal, and is arranged between the micro-groove group heat sink 4 and the main heat sink 1.

Example 1

In this embodiment, a microgroove group heat sink with porous medium material is provided inside the main heat sink 1 with a vacuum cavity 5 filled with a certain amount of phase change medium. The fin group 2 is composed of a number of fin monomers installed on the main heat sink 1 at equal intervals. The porous medium material 3 is a ceramic porous material or a foam metal and is tightly attached to the microgroove group heat sink 4. The microgroove group heat sink 4 is arranged at the bottom of the main heat sink 1 and is connected to the bottom of the vacuum cavity 5. The heat source is tightly fixed to the bottom surface of the microgroove group heat sink 4 through thermal interface materials such as thermal grease or thermal conductive silicone pads.

As shown in Figure 1, the main radiator 1 is a sunflower radiator with an outer diameter of 20~200mm and a height of 20~200mm. A vacuum cavity 5 is provided inside, and a micro-groove group heat sink 4 and a phase change medium are provided inside to enhance heat exchange. Among them, the phase change medium is at least one of distilled water, electronic fluoride liquid, deionized water, ethanol, methanol, liquid metal, etc., which has a low boiling point, is non-toxic, has stable chemical properties, and is not easy to react chemically with the inner wall of the main radiator 1. The fin group 2 is composed of a number of fin monomers with equal spacing and is arranged on the main radiator 1. The materials of the main radiator 1 and the fin group 2 are metals such as aluminum and copper or non-metals such as ceramics and plastics. The two can be processed into an integrated structure by extrusion or forging, and the fin group 2 can also be fixed to the main radiator 1 by welding, bonding, expansion or other mechanical methods. The setting of the vacuum cavity 5 can greatly reduce the weight of the radiator. The micro-groove heat sink 4 and the phase change medium can effectively improve the heat dissipation capacity of the radiator. The fin group installed on the main radiator 1 improves the external heat dissipation capacity and is more conducive to heat dissipation to the outside.

Example 2

As shown in Figure 2, a microgroove group heat sink with porous medium material in this embodiment is further improved on the basis of Example 1. The porous medium material 3 is in the shape of a torus with an inner diameter of 15-190 mm, an outer diameter of 20-200 mm, and a height of 1-5 mm. The material is ceramic or foam metal, which is used to absorb phase change working fluid. Ceramic porous materials have the advantages of low price, long service life, light weight, and oxidation resistance; foam metal has the advantages of controllable porosity, stable structure, and high temperature resistance. Both materials can be in close contact with the microgroove group heat sink 4.

Example 3

As shown in Figures 3-5, a microgroove group heat sink with porous medium material in this embodiment is further improved on the basis of Example 2, in order to make the porous medium material 3 and the microgroove group heat sink 4 in close contact. The microgroove group heat sink 4 is designed as a concentric cylinder with different diameters, and the radius of the upper cylinder is smaller than the radius of the lower cylinder. Among them, the outer diameter of the upper cylinder is 15~190mm and the height is 1~5mm, the outer diameter of the lower cylinder is 20~200mm and the height is 1~15mm, and the upper surface has uniformly distributed microgrooves, including N strips, wherein N≥10, the arrangement density is greater than 2 strips/cm, and the cross-section of the microgroove is a rectangle, triangle, trapezoid or other irregular shapes, and the dimensions are: groove width 20~5000µm, groove depth 20~5000µm, groove spacing 20~5000µm. The assembly of the porous medium material 3 and the microgroove group heat sink 4 is fixed to the bottom of the main radiator 1 by welding, bonding, expansion or other mechanical means. The maximum area ratio of the porous medium material 3 to the micro-groove group heat sink 4 is 7:9.

The combination of the porous medium material 3 and the micro-groove group heat sink 4 structural design improves the application range of the radiator. Under a certain liquid filling rate, it can adapt to a tilt angle of -90~90° and a rotation angle in any direction, ensuring that the micro-groove group heat sink and the phase change working medium are in continuous contact, thereby avoiding local dry burning of the micro-groove group heat sink.

A heat dissipation method using a microgroove group heat dissipation device with a porous medium material, wherein the heat generated by the heat source is transferred to the bottom surface of the microgroove group heat sink 4 by heat conduction through thermal grease or thermal silica gel. Due to the presence of the porous medium material 3, under certain tilt and rotation angles, the phase change medium in the main radiator 1 can contact the microgroove group heat sink 4 through the porous medium material 3, and the phase change medium enters the microgroove for heat exchange under the drive of the microgroove capillary force. Under an ideal state, a meniscus shape is formed in the microgroove, and the phase change medium has a strong evaporation heat exchange efficiency in the thin liquid film area of the meniscus, which can achieve high heat flux density heat exchange under low temperature rise. After the phase change medium liquid absorbs heat and evaporates into medium vapor, it condenses on the inner wall surface of the main radiator 1 and transfers the heat to the side wall of the main radiator 1. The heat is transferred to the fin group 2 by heat conduction through the side wall of the main radiator 1, and finally the fin group 2 and the external environment dissipate the heat to the external environment by natural convection heat transfer.

The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims (9)

1. A micro-slot group heat sink with porous dielectric material, comprising:

the main body radiator is internally provided with a vacuum cavity filled with a phase change working medium;

A fin group disposed outside the main body radiator, including a fin radiator;

the micro-groove group heat sink is arranged at the bottom of the main body radiator and is connected with the bottom of the vacuum cavity;

characterized by further comprising:

The porous medium material is fixedly arranged between the micro-groove group heat sink and the main body radiator, and the porous medium material enables the phase change working medium to be in contact with micro-grooves on the micro-groove group heat sink;

the micro-groove group heat sink is a different-diameter concentric cylinder, and the radius of the upper cylinder is smaller than that of the lower cylinder;

The porous medium material is a torus, the inner diameter of the torus is the same as the radius of the upper cylinder of the micro-groove group heat sink, the outer diameter of the torus is the same as the radius of the lower cylinder of the micro-groove group heat sink, and the height of the torus is the same as the height of the upper cylinder of the micro-groove group heat sink.

2. The micro-slot group heat sink with porous dielectric material of claim 1, wherein the porous dielectric material is ceramic or foam metal.

3. The micro-slot group heat sink with porous dielectric material of claim 2, wherein the maximum ratio of porous dielectric material to micro-slot group heat sink area is 7:9.

4. A micro-groove group heat sink with porous medium material as claimed in claim 3, wherein the upper surface of the upper cylinder of the micro-groove group heat sink is provided with uniformly distributed micro-grooves, and the cross section of the micro-grooves is one of rectangle, triangle and trapezoid.

5. The micro-groove group heat sink with porous dielectric material of claim 1, wherein the main body heat sink is a sunflower heat sink.

6. The micro-groove group heat dissipating device with porous medium material according to claim 5, wherein the fin heat sink in the fin group comprises 4 fins and N fins, N is greater than or equal to 16, the 4 fins are respectively symmetrical in center and perpendicular to each other, the periphery of the heat sink is divided into 4 areas in equal proportion, the fins are uniformly distributed in the four areas, and the number of the fins in each area is the same.

7. The micro-groove group heat sink with porous medium material according to claim 6, wherein the main body heat sink is integrally formed with the fin group or the fin group is connected to the main body heat sink.

8. The micro-groove group heat dissipating device with porous medium material of claim 1, wherein the phase change working medium comprises: distilled water, electronic fluoridation liquid, deionized water, ethanol, methanol and liquid metal.

9. The heat dissipation method of the micro-groove group heat dissipation device with the porous medium material is characterized in that the heat generation amount of a heat source is transferred to the bottom surface of the micro-groove group heat sink in a heat conduction mode through heat conduction silicone grease or heat conduction silica gel, and due to the existence of the porous medium material, under the condition of a certain inclination and rotation angle, a phase change working medium in the main body heat sink is contacted with the micro-groove group heat sink through the porous medium material, and enters the micro-groove to exchange heat under the driving of capillary force of the micro-groove; after the phase change working medium liquid absorbs heat and evaporates into working medium steam, the working medium steam is condensed on the inner wall surface of the main body radiator, the heat is transferred to the side wall of the main body radiator, the heat is transferred to the fin group through the side wall of the main body radiator again through heat conduction, and finally the fin group and the external environment dissipate the heat to the external environment through a natural convection heat transfer mode.