Micro-channel heat exchanger with bottom surface secondary textures and preparation method of micro-channel heat exchanger

Abstract

The invention discloses a microchannel heat exchanger with bottom surface secondary textures and a preparation method thereof.The microchannel heat exchanger comprises a microchannel substrate and a cover plate attached to the microchannel substrate, the microchannel substrate is provided with a plurality of microchannels, the bottom surfaces of the microchannels are provided with secondary texture structures, and the bottom surfaces of the microchannels are provided with secondary textures. The effects of disturbing flow, damaging a fluid boundary layer and increasing the heat exchange area are achieved, and the heat transfer performance is enhanced. The microchannel substrate is made of a third-generation semiconductor material, has excellent thermal conductivity and high temperature resistance, and can stably work in a high-temperature and high-pressure environment. When the microchannel heat exchanger is manufactured, the textured grinding wheel with the multiple abrasive particles distributed on the periphery moves on the to-be-machined face in the extending direction of the to-be-machined microchannels, the multiple parallel microchannels with the bottom face secondary texture structures are machined through grinding of the textured grinding wheel, the manufacturing process is simple, cost is low, and the microchannel heat exchanger is suitable for large-scale popularization and application. And integrated, high-efficiency and low-cost preparation and forming of the third-generation semiconductor material microchannel and the inner wall surface enhanced heat transfer microstructure can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchangers, and in particular to a microchannel heat exchanger with a bottom surface secondary texture and a preparation method thereof. Background Art

[0002] The third generation of semiconductor materials represented by silicon nitride (SiC), aluminum nitride (AlN), gallium nitride (GaN) etc. have excellent thermal conductivity, high temperature resistance and good chemical stability. They are widely used in chips and devices such as power electronics, optoelectronics, energy storage and conversion, and play an important role in automotive electronics, power electronics, aerospace and other fields. However, with the increase in the integration of chips and devices, extremely high heat is generated in a small space, causing the heat flux density inside the chips and devices to increase rapidly, facing serious heat dissipation and cooling problems. Microchannel heat exchangers have the advantages of small size, compact structure and high heat exchange efficiency, and have significant advantages in heat dissipation and cooling of high heat flux density devices.

[0003] Existing microchannel heat exchangers are generally made by processing a number of equally spaced triangular, rectangular, trapezoidal or circular microchannels on a metal substrate, but they have problems such as smooth channel walls, small heat exchange area, limited heat transfer performance, and low critical heat flux density, making it difficult to meet the increasingly stringent high-frequency, high-power, high-temperature and high-pressure working requirements of third-generation semiconductor chips and devices. It is urgent to develop a microchannel heat exchanger with higher heat transfer performance that can meet the heat exchange performance requirements under high frequency, high power, high temperature and high pressure environments.

[0004] Third-generation semiconductor materials such as silicon nitride, aluminum nitride, and gallium nitride are hard and brittle materials, which are prone to fracture or brittle failure during processing. Existing methods such as electrospark machining, laser machining, and ultrasonic machining are difficult to achieve machining accuracy and quality control, and have defects such as low machining efficiency and poor machining quality in microstructure preparation; while chemical mechanical polishing methods have strict requirements on machining fluid and process environment, high process cost, and are usually used for plane machining, making it difficult to achieve three-dimensional complex microstructure preparation. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide a microchannel heat exchanger with a secondary texture on the bottom surface, which can meet the heat exchange performance requirements under high frequency, high power, high temperature and high pressure environment.

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows: a microchannel heat exchanger with a secondary texture on the bottom surface, comprising a microchannel substrate and a cover plate, the microchannel substrate is made of a third-generation semiconductor material, a plurality of microchannels are provided on the microchannel substrate, the bottom surface of the microchannel has a secondary texture structure, the cross-section of the bottom surface secondary texture structure is a triangle or a partially superimposed triangle, the substrate is covered on the microchannel substrate, and a cooling medium inlet and a cooling medium outlet connected to the microchannel are provided on the cover plate.

[0007] In the above-mentioned microchannel heat exchanger with bottom surface secondary texture, the microchannel is composed of a rectangular slit and a secondary texture structure arranged on the bottom surface of the rectangular slit.

[0008] In the above-mentioned microchannel heat exchanger with bottom surface secondary texture, the plurality of microchannels are equidistant and parallel.

[0009] In the above-mentioned microchannel heat exchanger with bottom surface secondary texture, the material of the microchannel substrate is silicon nitride, aluminum nitride or gallium nitride.

[0010] The present invention also provides a method for preparing a microchannel heat exchanger having a bottom surface secondary texture, which is used to prepare the above-mentioned microchannel heat exchanger having a bottom surface secondary texture, comprising the following steps:

[0011] S1. preparing a textured grinding wheel, wherein a plurality of raised abrasive grains are evenly distributed on the periphery of the textured grinding wheel, and the plurality of abrasive grains are distributed in an array;

[0012] S2, fixing the textured grinding wheel on the spindle of a milling machine;

[0013] S3, fixing the blank of the microchannel substrate on the fixture of the XY axis platform, making one side of the plane to be processed close to the textured grinding wheel, and making the textured grinding wheel tangent to the bottom surface of the microchannel to be processed, and moving the blank to the starting position of one end of the microchannel to be processed through the XY axis platform;

[0014] S4, starting the spindle of the milling machine to rotate the textured grinding wheel, and moving the textured grinding wheel along the extension direction of the microchannel to be processed, and grinding the rectangular slit and the secondary texture structure of the bottom surface thereof by the textured grinding wheel;

[0015] S5, deburring and cleaning the processed parts to obtain the required microchannel substrate;

[0016] S6. Prepare a cover plate, and attach the cover plate to the microchannel substrate to obtain the desired microchannel heat exchanger with a bottom surface secondary texture.

[0017] In the above-mentioned method for preparing a microchannel heat exchanger with a bottom surface secondary texture, the abrasive particles are of a conical structure.

[0018] The above-mentioned method for preparing a microchannel heat exchanger with a secondary texture on the bottom surface is as follows: the interval between the cone vertices of each two adjacent conical structures along the direction of the center line of the textured grinding wheel is 0.1mm~0.3mm, the cone height of the conical structure is 0.1mm~0.2mm, and the diameter of the cone bottom circle of the conical structure is 0.2mm~0.4mm.

[0019] In the above-mentioned method for preparing a microchannel heat exchanger with a bottom surface secondary texture, in step S2, a plurality of textured grinding wheels are provided, and the plurality of textured grinding wheels are arranged in parallel and fixed on a spindle of a milling machine at set intervals.

[0020] In the above-mentioned method for preparing a microchannel heat exchanger with a bottom surface secondary texture, the thickness of the textured grinding wheel is 0.5 mm to 3 mm, and the diameter of the grinding wheel is 10 mm to 50 mm.

[0021] In the above-mentioned method for preparing a microchannel heat exchanger with a bottom secondary texture, the rotation speed of the textured grinding wheel is 1000r / min-4000r / min, the feed speed is 0.075m / min-1.5m / min, and the cutting depth is 0.5mm-3mm.

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The bottom surface of the microchannel of the microchannel heat exchanger is provided with a secondary texture structure, which can significantly increase the heat exchange area, destroy the normal development of the fluid and thermal boundary layer, play a turbulent role, and thus significantly enhance the heat exchange performance.

[0025] 2) The microchannel substrate of the microchannel heat exchanger is made of third-generation semiconductor materials, which has excellent thermal conductivity and high temperature resistance. It can work stably under high frequency, high power, high temperature and high pressure environment to meet higher heat exchange performance requirements. In addition, when the microchannel heat exchanger made of third-generation semiconductor materials is applied to third-generation semiconductor chips or devices, the physical properties of the two, such as modulus and thermal expansion coefficient, are more matched, which has the advantages of easy packaging and improved reliability.

[0026] 3) This preparation method is to use an array thin-film grinding wheel on a milling machine to grind the microchannel array of the third-generation semiconductor material. The outer periphery of the textured grinding wheel is evenly distributed with multiple raised abrasive grains, which can realize the single-process integrated forming of the array microchannel and its bottom secondary texture structure. The use of a grinding wheel grinding method solves the problem that the third-generation semiconductor material is a hard and brittle material and cannot be processed by conventional methods. It can significantly improve processing efficiency and reduce processing costs. It does not require complex manufacturing processes and is easy to achieve mass production.

[0027] 4) Designing abrasive grains on the surface of the textured grinding wheel can also reduce the processing temperature, effectively reduce the cutting force and the thermal impact of the processing process on hard and brittle materials, and improve the surface quality of the workpiece and the life of the textured grinding wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 An exploded view of a microchannel heat exchanger according to an embodiment of the present invention;

[0029] Figure 2 is a schematic structural diagram of a microchannel substrate according to an embodiment of the present invention;

[0030] Figure 3 Schematic diagram of the structure of a textured grinding wheel according to an embodiment of the present invention, wherein: Figure 3 The structure on the left is a schematic diagram of the local structure of the periphery of the textured grinding wheel;

[0031] Figure 4 A schematic diagram of grinding a microchannel substrate using a textured grinding wheel or other structures according to an embodiment of the present invention;

[0032] Explanation of the accompanying figures: 1-motor, 11-spindle, 12-grinding wheel slot, 2-microchannel substrate, 21-rectangular slit, 211-secondary texture structure, 22-outlet liquid reservoir, 23-inlet liquid reservoir, 3-textured grinding wheel, 31-grinding wheel center hole, 32-abrasive, 4-clamp, 41-vertical clamp, 42-horizontal clamp, 5-XY axis platform, 51-X axis platform, 52-Y axis platform, 6-cover plate, 61-cooling medium inlet, 62-cooling medium outlet. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below. Figure 1 and Figure 2The embodiment of the present invention provides a microchannel heat exchanger with a bottom surface secondary texture, including a microchannel substrate 2 and a cover plate 6. The microchannel substrate 2 is provided with a plurality of microchannels, the substrate is attached to the microchannel substrate 2, and the cover plate 6 is provided with a cooling medium inlet 61 and a cooling medium outlet 62 connected to the microchannels. The cooling medium enters the inlet reservoir 23 from the side of the cooling medium inlet 61 on the cover plate 6, passes through a number of microchannels, enters the outlet reservoir 22, and finally is discharged from the side of the cooling medium outlet 62 on the cover plate 6 to complete the heat exchange. The bottom surface of the microchannel has a secondary texture structure 211, and the plurality of microchannels are equidistant and parallel. The microchannel is composed of a rectangular slit 21 and a secondary texture structure 211 arranged on the bottom surface of the rectangular slit 21. The cross section of the bottom surface secondary texture structure 211 is a triangle or a partially superimposed triangle, which has the functions of disturbing the flow, destroying the fluid boundary layer, and increasing the heat exchange area, providing more vaporization cores for the generation of bubbles, which can significantly enhance the heat exchange performance and better meet the heat exchange requirements of modern equipment. The microchannel substrate 2 is made of third-generation semiconductor materials, such as silicon nitride, aluminum nitride, gallium nitride and other materials, which have excellent thermal conductivity and high temperature resistance, and good chemical stability, and can work stably under high frequency, high power and high temperature and high pressure environment, meeting higher heat exchange performance requirements. In addition, when the microchannel heat exchanger made of third-generation semiconductor materials is applied to third-generation semiconductor chips or devices, the physical properties of the two, such as modulus and thermal expansion coefficient, are more matched, which has the advantages of easy packaging and improved reliability.

[0034] Since the microchannel substrate 2 in the present microchannel heat exchanger is made of third-generation semiconductor materials, third-generation semiconductor materials such as silicon nitride, aluminum nitride, and gallium nitride are hard and brittle materials, and are prone to fracture or brittle failure during processing. Existing methods such as electrospark machining, laser machining, and ultrasonic machining are difficult to achieve control of machining accuracy and quality, and have defects such as low machining efficiency and poor machining quality in microstructure preparation; while the chemical mechanical polishing method has strict requirements on the machining fluid and process environment, has high process costs, and is usually used for plane machining, and is difficult to achieve three-dimensional complex microstructure preparation. Therefore, in order to obtain the microchannel heat exchanger in this scheme, a method is needed to process a microchannel with a bottom secondary texture structure 211 on a third-generation semiconductor material microchannel substrate 2. Therefore, referring to Figure 3 and Figure 4 The embodiment of the present invention further provides a method for preparing a microchannel heat exchanger having a bottom surface secondary texture, which is used to prepare the above-mentioned microchannel heat exchanger having a bottom surface secondary texture, comprising the following steps:

[0035] S1, preparing a textured grinding wheel 3, wherein a plurality of raised abrasive grains 32 are evenly distributed on the periphery of the textured grinding wheel 3, and the plurality of abrasive grains 32 are distributed in an array;

[0036] S2, fixing the textured grinding wheel 3 on the milling machine spindle 11;

[0037] S3, fix the blank of the microchannel substrate 2 on the fixture 4 of the XY axis platform 5, make one side of the plane to be processed close to the textured grinding wheel 3, and make the textured grinding wheel 3 tangent to the bottom surface of the microchannel to be processed, and move the blank to the starting position of one end of the microchannel to be processed through the XY axis platform 5;

[0038] S4, starting the milling machine spindle 11 to rotate the textured grinding wheel 3, and moving the textured grinding wheel 3 along the extension direction of the microchannel to be processed, and grinding the rectangular slit 21 and the secondary texture structure 211 on the bottom surface thereof by the textured grinding wheel 3;

[0039] S5, deburring and cleaning the processed parts to obtain the required microchannel substrate 2;

[0040] S6. Prepare the cover plate 6 and attach the cover plate 6 to the microchannel substrate 2 to obtain the desired microchannel heat exchanger with a bottom surface secondary texture.

[0041] The preparation method can prepare the above-mentioned microchannel heat exchanger with the bottom secondary texture, so it has at least all the beneficial effects that the above-mentioned microchannel heat exchanger with the bottom secondary texture can bring. In addition, the preparation method has a plurality of raised abrasive grains 32 evenly distributed on the periphery of the textured grinding wheel 3, and the microchannel and its bottom secondary texture structure 211 can be formed at one time by grinding. The grinding wheel grinding method solves the problem that the third-generation semiconductor material is a hard and brittle material and cannot be processed by conventional methods. It does not require a complex manufacturing process, has a low production cost, and has a high production efficiency, and is easy to realize industrial production. Moreover, by designing abrasive grains 32 on the surface of the textured grinding wheel 3, the surface of the workpiece can be ground and trimmed by the textured grinding wheel 3, thereby achieving processing efficiency with high precision and good surface quality, and can also reduce the processing temperature, effectively reducing the cutting force and the thermal impact of the processing process on the hard and brittle materials, and improving the surface quality of the workpiece and the life of the textured grinding wheel 3. The microchannel with a bottom secondary texture can be completely processed on the microchannel substrate 2 by grinding, and no fracture or brittle failure will occur.

[0042] Further, in step S1, the abrasive grains 32 on the periphery of the textured grinding wheel 3 are of a conical structure, such as Figure 3As shown, the abrasive grains 32 are distributed in multiple layers along the axis direction of the textured grinding wheel 3, each layer has multiple abrasive grains 32, and the multiple abrasive grains 32 on each layer are evenly distributed along the circumference of the textured grinding wheel 3. The cross section of the bottom secondary texture structure 211 processed by such a textured grinding wheel 3 is a triangle superposition. In the design stage, the cone size and cone array distribution of the abrasive grains 32 are first determined, and then the laser processing method is used to manufacture the following triangles on the CVD diamond. Figure 3 The textured grinding wheel 3 is a micro-abrasive grain 32 array with controllable size, spacing and crystal orientation. The thickness of the textured grinding wheel 3 is 0.5mm-3mm, the diameter of the grinding wheel is 10mm-50mm, the cone vertices of each adjacent conical structure are spaced along the direction of the center line of the textured grinding wheel 3, that is, the center distance is 0.1mm-0.3mm, the cone height of the conical structure is 0.1mm-0.2mm, and the diameter of the cone bottom circle of the conical structure is 0.2mm-0.4mm. These dimensions can be selected and determined according to needs in the actual application process. For example, in this embodiment, a diamond with a diameter of 50mm and a thickness of 1mm is selected, and a conical abrasive grain 32 is processed on its periphery, wherein the diameter of the cone bottom circle of the abrasive grain 32 is 0.3mm, the cone height is 0.3mm, and the center distance between each adjacent two abrasive grains 32 is 0.2mm.

[0043] Further, in step S2, a plurality of textured grinding wheels 3 may be provided, and the plurality of textured grinding wheels 3 may be arranged at set intervals, the grinding wheel center holes 31 of the textured grinding wheels 3 may be sleeved on the milling machine spindle 1 and the textured grinding wheels 3 may be fixed in the grinding wheel slot 12, so that the plurality of textured grinding wheels 3 may be arranged in parallel along the axial direction and fixed on the milling machine spindle 11. By installing the plurality of textured grinding wheels 3, a one-time forming process of the microchannel substrate 2 may be achieved. In this embodiment, four textured grinding wheels 3 may be arranged in parallel and fixed on the milling machine spindle 11 at intervals of 1.3 mm.

[0044] In step S3, the blank material of the microchannel substrate 2 is silicon nitride, and the size is 80 mm long*40 mm wide*10 mm high. The blank of the microchannel substrate 2 is fixed by a fixture 4, such as Figure 4 As shown, the fixture 4 includes a vertical fixture 41 and a horizontal fixture 42. The blank is first fixed on the vertical fixture 41, and then the vertical fixture 41 is fixed on the horizontal fixture 42, so that one side of the plane to be processed is close to the textured grinding wheel 3, and the textured grinding wheel 3 is ensured to be tangent to the bottom surface of the microchannel to be processed, and the blank is moved to the starting position of one end of the microchannel to be processed through the XY axis platform 5. Among them, the XY axis platform 5 includes an X axis platform 51 and a Y axis platform 52, the X axis platform 51 is slidably mounted on the Y axis platform 52, and the fixture 4 is mounted on the X axis platform 51.

[0045] In step S4, the rotation speed of the textured grinding wheel 3 is 1000r / min-4000r / min, the feed speed is 0.075m / min-1.5m / min, and the cutting depth is 0.5mm-3mm. In this embodiment, the rotation speed of the textured grinding wheel 3 is set to 3000r / min, the feed speed is 60mm / min, and the grinding depth is 0.5mm. Four rectangular slits 21 with a depth of 1mm are processed twice, and then the blank is moved to the processing initial position of the next four rectangular slits 21 to be processed by the XY axis platform 5, and the grinding operation is repeated.

[0046] In step S5, the ground microchannel substrate 2 is placed in an ultrasonic cleaning machine filled with anhydrous ethanol for cleaning for 20 minutes, and then taken out and dried.

[0047] In step S6, the lower surface of the prepared cover plate 6 and the upper surface of the microchannel substrate 2 dried in step S5 are sealed and fixed together by welding, and connected with a water pump and a pipeline to form a forced circulation loop to obtain a complete microchannel heat exchanger.

[0048] It should be noted that in the description of the present invention, if there are any orientation descriptions, such as up, down, front, back, left, right, etc., the orientations or positional relationships indicated are all based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing 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 or operated in a specific orientation, and cannot be understood as a limitation on the present invention.

[0049] In the description of the present invention, "several" means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0050] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0051] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A microchannel heat exchanger with a bottom surface secondary texture, characterized in that: The invention comprises a microchannel substrate (2) and a cover plate (6), wherein the microchannel substrate (2) is made of a third-generation semiconductor material, a plurality of microchannels are provided on the microchannel substrate (2), the bottom surface of the microchannel has a secondary texture structure (211), the cross section of the bottom surface secondary texture structure (211) is in the shape of a triangle or a partially superimposed triangle, the cover plate (6) is attached to the microchannel substrate (2), and a cooling medium inlet (61) and a cooling medium outlet (62) which are in communication with the microchannels are provided on the cover plate (6).

2. The microchannel heat exchanger with bottom surface secondary texture according to claim 1, characterized in that: The microchannel is composed of a rectangular slit (21) and a secondary texture structure (211) arranged on the bottom surface of the rectangular slit (21).

3. The microchannel heat exchanger with bottom surface secondary texture according to claim 1, characterized in that: The plurality of microchannels are equidistant and parallel to each other.

4. The microchannel heat exchanger with bottom surface secondary texture according to claim 1, characterized in that: The material of the microchannel substrate (2) is silicon nitride, aluminum nitride or gallium nitride.

5. A method for preparing a microchannel heat exchanger having a bottom surface secondary texture, characterized in that: The method for preparing a microchannel heat exchanger having a bottom surface secondary texture as claimed in any one of claims 1 to 4 comprises the following steps: S1. preparing a textured grinding wheel (3), wherein a plurality of raised abrasive grains (32) are evenly distributed on the periphery of the textured grinding wheel (3), and the plurality of abrasive grains (32) are distributed in an array; S2, fixing the textured grinding wheel (3) on a milling machine spindle (11); S3, fixing the blank of the microchannel substrate (2) on the fixture (4) of the XY axis platform (5), making one side of the plane to be processed close to the textured grinding wheel (3), and making the textured grinding wheel (3) tangent to the bottom surface of the microchannel to be processed, and moving the blank to the starting position of one end of the microchannel to be processed through the XY axis platform (5); S4, starting the spindle (11) of the milling machine to rotate the textured grinding wheel (3), and moving the textured grinding wheel (3) along the extension direction of the microchannel to be processed, and grinding the rectangular slit (21) and the secondary texture structure (211) on the bottom surface thereof by the textured grinding wheel (3); S5, deburring and cleaning the processed parts to obtain the desired microchannel substrate (2); S6. Prepare a cover plate (6), and attach and fix the cover plate (6) to the microchannel substrate (2), so as to obtain the desired microchannel heat exchanger with a bottom surface secondary texture.

6. The method for preparing a microchannel heat exchanger having a bottom surface secondary texture according to claim 5, characterized in that: The abrasive grains (32) are of a conical structure.

7. The method for preparing a microchannel heat exchanger having a bottom surface secondary texture according to claim 6, characterized in that: The cone vertices of each of two adjacent cone-shaped structures are spaced 0.1 mm to 0.3 mm in the direction of the center line of the textured grinding wheel (3), the cone height of the cone-shaped structure is 0.1 mm to 0.2 mm, and the diameter of the cone bottom circle of the cone-shaped structure is 0.2 mm to 0.4 mm.

8. The method for preparing a microchannel heat exchanger having a bottom surface secondary texture according to claim 5, characterized in that: In step S2, a plurality of textured grinding wheels (3) are provided, and the plurality of textured grinding wheels (3) are arranged in parallel at set intervals and fixed on a milling machine spindle (11).

9. The method for preparing a microchannel heat exchanger having a bottom surface secondary texture according to claim 5, characterized in that: The textured grinding wheel (3) has a thickness of 0.5 mm to 3 mm and a grinding wheel diameter of 10 mm to 50 mm.

10. The method for preparing a microchannel heat exchanger having a bottom surface secondary texture according to claim 5, characterized in that: The rotation speed of the textured grinding wheel (3) is 1000 r / min-4000 r / min, the feed speed is 0.075 m / min-1.5 m / min, and the cutting depth is 0.5 mm-3 mm.

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