Microchannel heat exchanger with bottom secondary texture and method of making same

Abstract

The application discloses a micro-channel heat exchanger with a bottom secondary texture and a preparation method thereof. The micro-channel heat exchanger comprises a micro-channel substrate and a cover plate attached to the micro-channel substrate. A plurality of micro-channels are formed on the micro-channel substrate. The bottom surface of the micro-channel has a secondary texture structure, which has the effects of disturbing flow, destroying the fluid boundary layer, increasing the heat exchange area and enhancing the heat transfer performance. The micro-channel substrate is made of a third-generation semiconductor material, which has excellent thermal conductivity and high-temperature resistance and can work stably in a high-temperature and high-pressure environment. When the micro-channel heat exchanger is prepared, a textured grinding wheel with a plurality of abrasive grains distributed on the outer periphery is moved on a surface to be machined along the extension direction of the micro-channels to be machined, and a plurality of parallel micro-channels with the bottom secondary texture structure are processed by the textured grinding wheel, so that the manufacturing process is simple, the cost is low, and the third-generation semiconductor material micro-channel and the inner wall surface heat transfer strengthening micro-structure can be integrally, efficiently and low-cost prepared.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger technology, specifically to a microchannel heat exchanger with a secondary texture on the bottom surface and its preparation method. Background Technology

[0002] Third-generation semiconductor materials, such as silicon nitride (SiC), aluminum nitride (AlN), and gallium nitride (GaN), possess excellent thermal conductivity, high-temperature resistance, and good chemical stability, and are widely used in chips and devices for power electronics, optoelectronics, and energy storage and conversion. They also play a crucial role in automotive electronics, power electronics, and aerospace. However, with the increasing integration of chips and devices, extremely high heat is generated within confined spaces, causing a rapid increase in internal heat flux density and posing a serious challenge to heat dissipation and cooling. Microchannel heat exchangers offer advantages such as small size, compact structure, and high heat exchange efficiency, demonstrating significant advantages in cooling high heat flux density devices.

[0003] Existing microchannel heat exchangers typically involve fabricating numerous equidistantly arranged triangular, rectangular, trapezoidal, or circular microchannels on a metal substrate. However, these methods suffer from drawbacks 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 demanding high-frequency, high-power, high-temperature, and high-pressure operating requirements of third-generation semiconductor chips and devices. There is an urgent need to develop a microchannel heat exchanger with higher heat transfer performance that can meet the heat exchange performance requirements under high-frequency, high-power, and high-temperature, high-pressure environments.

[0004] Third-generation semiconductor materials such as silicon nitride, aluminum nitride, and gallium nitride are hard and brittle, prone to fracture or brittle fracture during processing. Existing methods such as electrical discharge machining, laser machining, and ultrasonic machining are difficult to control in terms of processing precision and quality, and suffer from low processing efficiency and poor processing quality in microstructure fabrication. On the other hand, chemical mechanical polishing requires strict control over the processing fluid and process environment, has high processing costs, and is usually used for planar processing, making it difficult to fabricate complex three-dimensional microstructures. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of this 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 and high temperature and high pressure environments.

[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, wherein the microchannel substrate is made of a third-generation semiconductor material, and multiple microchannels are formed on the microchannel substrate, wherein the bottom surface of the microchannel has a secondary texture structure, and the cross-section of the secondary texture structure on the bottom surface is triangular or partially superimposed triangular, the substrate is covered on the microchannel substrate, and the cover plate has a cooling medium inlet and a cooling medium outlet communicating with the microchannel.

[0007] The aforementioned microchannel heat exchanger with a secondary texture on the bottom surface comprises a rectangular slit and a secondary texture structure disposed on the bottom surface of the rectangular slit.

[0008] The aforementioned microchannel heat exchanger with a secondary texture on the bottom surface has multiple microchannels that are equidistant and parallel.

[0009] The microchannel heat exchanger with a secondary texture on the bottom surface described above is made of silicon nitride, aluminum nitride, or gallium nitride.

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

[0011] S1. Prepare a textured grinding wheel, wherein the textured grinding wheel has a plurality of raised abrasive grains evenly distributed on its outer periphery, and the plurality of abrasive grains are arranged in an array.

[0012] S2. Fix the textured grinding wheel onto the milling machine spindle;

[0013] S3. Fix the blank of the microchannel substrate on the fixture of the XY-axis platform, so that one side of the plane to be processed is close to the textured grinding wheel, and the textured grinding wheel is tangent to the bottom surface of the microchannel to be processed. Move the blank to the starting position of one end of the microchannel to be processed through the XY-axis platform.

[0014] S4. Start the milling machine spindle to rotate the textured grinding wheel and move the textured grinding wheel along the extension direction of the microchannel to be processed, and grind the rectangular slit and its bottom surface secondary texture structure through the textured grinding wheel.

[0015] S5. Deburr and clean 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 secondary texture on the bottom surface.

[0017] In the above-described method for preparing a microchannel heat exchanger with a secondary bottom texture, the abrasive grains have a conical structure.

[0018] In the above-mentioned method for preparing a microchannel heat exchanger with a secondary bottom texture, the vertices of two adjacent conical structures are spaced 0.1 mm to 0.3 mm apart along the direction of the center line of the textured grinding wheel, the height of the conical structure is 0.1 mm to 0.2 mm, and the diameter of the bottom circle of the conical structure is 0.2 mm to 0.4 mm.

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

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

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

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1) The microchannel bottom surface of the microchannel heat exchanger has a secondary textured structure, which can significantly increase the heat exchange area, disrupt the normal development of the fluid and thermal boundary layer, play a turbulence role, and thus significantly enhance the heat exchange performance.

[0025] 2) The microchannel substrate of this microchannel heat exchanger is made of third-generation semiconductor material, which has excellent thermal conductivity and high temperature resistance, enabling it to operate stably under high frequency, high power, and high temperature and high pressure environments, meeting higher heat exchange performance requirements. Furthermore, when microchannel heat exchangers made of third-generation semiconductor material are applied to third-generation semiconductor chips or devices, the physical properties such as modulus and coefficient of thermal expansion are more well-matched, offering advantages such as easier packaging and improved reliability.

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

[0027] 4) Designing abrasive grains on the surface of textured grinding wheels can also reduce the processing temperature, effectively reduce the cutting force and the thermal impact of the processing on hard and brittle materials, and improve the surface quality of the workpiece and the life of the textured grinding wheel. Attached Figure Description

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

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

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

[0031] Figure 4 This is a schematic diagram of grinding a microchannel substrate using a textured grinding wheel or similar structure, according to an embodiment of the present invention.

[0032] Explanation of reference numerals: 1-Motor, 11-Spindle, 12-Grinding wheel slot, 2-Microchannel substrate, 21-Rectangular slit, 211-Secondary textured structure, 22-Outlet reservoir, 23-Inlet reservoir, 3-Textured grinding wheel, 31-Grinding wheel center hole, 32-Abrasive grain, 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 Implementation

[0033] The embodiments of the present invention are described in detail below, with reference to... Figure 1 and Figure 2This invention provides a microchannel heat exchanger with a secondary texture on the bottom surface, comprising a microchannel substrate 2 and a cover plate 6. Multiple microchannels are formed on the microchannel substrate 2, and the substrate is attached to the microchannel substrate 2. The cover plate 6 has a cooling medium inlet 61 and a cooling medium outlet 62 communicating with the microchannels. The cooling medium enters the inlet reservoir 23 from the cooling medium inlet 61 side of the cover plate 6, passes through several microchannels, enters the outlet reservoir 22, and finally exits from the cooling medium outlet 62 side of the cover plate 6, completing the heat exchange. The bottom surface of the microchannels has a secondary texture structure 211. The multiple microchannels are equidistant and parallel. Each microchannel is composed of a rectangular slit 21 and a secondary texture structure 211 located on the bottom surface of the rectangular slit 21. The cross-section of the secondary texture structure 211 is triangular or partially superimposed triangular, which has the functions of turbulence, disrupting the fluid boundary layer, and increasing the heat exchange area. It provides more vaporization nuclei for bubble generation, significantly enhancing heat exchange performance and better meeting the heat exchange requirements of modern equipment. The microchannel substrate 2 is made of third-generation semiconductor materials, such as silicon nitride, aluminum nitride, and gallium nitride. These materials possess excellent thermal conductivity and high-temperature resistance, as well as good chemical stability, enabling stable operation under high frequency, high power, and high temperature and pressure conditions, thus meeting higher heat exchange performance requirements. Furthermore, when microchannel heat exchangers made of third-generation semiconductor materials are applied to third-generation semiconductor chips or devices, the physical properties of both are more well-matched, such as modulus and coefficient of thermal expansion, offering advantages such as easier packaging and improved reliability.

[0034] Since the microchannel substrate 2 in this microchannel heat exchanger is made of third-generation semiconductor materials, such as silicon nitride, aluminum nitride, and gallium nitride, these materials are hard and brittle, prone to fracture or brittle damage during processing. Existing methods such as electrical discharge machining, laser machining, and ultrasonic machining are difficult to control in terms of processing precision and quality, resulting in low processing efficiency and poor processing quality in microstructure fabrication. Chemical mechanical polishing (CMP) requires strict control over the processing fluid and environment, has high processing costs, and is typically used for planar processing, making it difficult to fabricate complex three-dimensional microstructures. Therefore, to obtain the microchannel heat exchanger in this solution, a method is needed to fabricate microchannels with a bottom secondary texture structure 211 on the third-generation semiconductor material microchannel substrate 2. Therefore, referring to… Figure 3 and Figure 4 The present invention also provides a method for preparing a microchannel heat exchanger with a bottom secondary texture, which is used to prepare the above-mentioned microchannel heat exchanger with a bottom secondary texture, comprising the following steps:

[0035] S1. Prepare a textured grinding wheel 3, wherein a plurality of raised abrasive grains 32 are uniformly distributed on the outer periphery of the textured grinding wheel 3, and the plurality of abrasive grains 32 are arranged in an array.

[0036] S2. Fix the textured grinding wheel 3 onto the milling machine spindle 11;

[0037] S3. Fix the blank of the microchannel substrate 2 on the clamp 4 of the XY axis platform 5, 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 tangent to the bottom surface of the microchannel to be processed. Move the blank to the starting position of one end of the microchannel to be processed through the XY axis platform 5.

[0038] S4. Start the milling machine spindle 11 to rotate the textured grinding wheel 3 and move the textured grinding wheel 3 along the extension direction of the microchannel to be processed. The textured grinding wheel 3 grinds and processes the rectangular slit 21 and the secondary texture structure 211 on its bottom surface.

[0039] S5. Deburr and clean the processed parts to obtain the required microchannel substrate 2.

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

[0041] This preparation method can produce the microchannel heat exchanger with a secondary bottom texture as described above. Therefore, it possesses at least all the beneficial effects that a microchannel heat exchanger with a secondary bottom texture can provide. Furthermore, this preparation method uniformly distributes multiple raised abrasive grains 32 on the outer periphery of the textured grinding wheel 3. By employing grinding, the microchannel and its secondary bottom texture structure 211 can be formed in one step. Using grinding wheel machining solves the problem that third-generation semiconductor materials are hard and brittle and cannot be processed using conventional methods. It eliminates the need for complex manufacturing processes, resulting in low production costs, high production efficiency, and easy industrialization. Furthermore, by designing abrasive grains 32 on the surface of the textured grinding wheel 3, the surface of the workpiece can be ground and dressed by the textured grinding wheel 3, achieving high precision and good surface quality processing efficiency. It can also reduce the processing temperature, effectively reduce the cutting force and the thermal impact of the processing on hard and brittle materials, improve 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 without fracture or brittle damage.

[0042] Furthermore, in step S1, the abrasive grains 32 on the outer periphery of the textured grinding wheel 3 have a conical structure, such as... Figure 3As shown, the abrasive grains 32 are distributed in multiple layers along the axial direction of the textured grinding wheel 3, with each layer containing multiple abrasive grains 32. These multiple abrasive grains 32 are evenly distributed circumferentially along the textured grinding wheel 3. The cross-section of the secondary texture structure 211 on the bottom surface produced by this type of textured grinding wheel 3 is a superposition of triangles. In the design phase, the cone size and cone array distribution of the abrasive grains 32 are first determined, and then laser processing is used to fabricate a texture structure like this on CVD diamond. Figure 3 The textured abrasive wheel 3 is an array of micro-abrasive grains 32 with controllable dimensions, spacing, and crystal orientation. The textured abrasive wheel 3 has a thickness of 0.5 mm to 3 mm, a diameter of 10 mm to 50 mm, and the vertices of each adjacent conical structure are spaced 0.1 mm to 0.3 mm apart along the center line of the textured abrasive wheel 3. The cone height of the conical structure is 0.1 mm to 0.2 mm, and the diameter of the cone's base circle is 0.2 mm to 0.4 mm. These dimensions can be selected and determined according to requirements in practical applications. For example, in this embodiment, a diamond with a diameter of 50 mm and a thickness of 1 mm is selected, and conical abrasive grains 32 are machined on its outer periphery. The diameter of the cone's base circle of the abrasive grain 32 is 0.3 mm, the cone height is 0.3 mm, and the center distance between each adjacent abrasive grain 32 is 0.2 mm.

[0043] Further, in step S2, multiple textured grinding wheels 3 can be provided, and the textured grinding wheels 3 are fitted onto the milling machine spindle 1 with their center holes 31 at a set interval, and the textured grinding wheels 3 are fixedly installed in the grinding wheel slots 12, so that the multiple textured grinding wheels 3 are arranged parallel to each other along the axial direction and fixed on the milling machine spindle 11. By installing multiple textured grinding wheels 3, the microchannel substrate 2 can be formed in one step. In this embodiment, four textured grinding wheels 3 are arranged parallel to each other and fixed on the milling machine spindle 11 with a spacing of 1.3 mm.

[0044] In step S3, the blank material of the microchannel substrate 2 is silicon nitride, with dimensions of 80mm (length) * 40mm (width) * 10mm (height). The blank of the microchannel substrate 2 is fixed using clamp 4. Figure 4 As shown, the fixture 4 includes a vertical fixture 41 and a horizontal fixture 42. First, the blank is 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 surface to be processed is close to the textured grinding wheel 3, ensuring that the textured grinding wheel 3 is tangent to the bottom surface of the microchannel to be processed. The blank is then moved to the starting position at one end of the microchannel to be processed via the XY-axis platform 5. 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 rotational speed of the textured grinding wheel 3 is 1000 r / min-4000 r / min, the feed rate is 0.075 m / min-1.5 m / min, and the depth of cut is 0.5 mm-3 mm. In this embodiment, the rotational speed of the textured grinding wheel 3 is set to 3000 r / min, the feed rate is 60 mm / min, and the grinding depth is 0.5 mm. The four rectangular slits 21 with a depth of 1 mm are processed twice. Then, the blank is moved to the 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 cleaner containing anhydrous ethanol for 20 minutes and then removed and dried.

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

[0048] It should be noted that in the description of this invention, any descriptions of orientation, such as up, down, front, back, left, right, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this 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 should not be construed as a limitation of this invention.

[0049] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, while "above," "below," "within," etc. are understood to include the stated number. If "first" or "second" is mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0050] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0051] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a microchannel heat exchanger with a secondary texture on the bottom surface, characterized in that, For the fabrication of a microchannel heat exchanger with a secondary texture on the bottom surface, the microchannel heat exchanger with a secondary texture on the bottom surface includes a microchannel substrate (2) and a cover plate (6). The microchannel substrate (2) is made of a third-generation semiconductor material. Multiple microchannels are formed on the microchannel substrate (2). The bottom surface of the microchannel has a secondary texture structure (211). The cross-section of the secondary texture structure (211) is triangular. The cover plate (6) is attached to the microchannel substrate (2). The cover plate (6) has a cooling medium inlet (61) and a cooling medium outlet (62) communicating with the microchannel. The preparation method includes the following steps: S1. Prepare a textured grinding wheel (3), wherein the textured grinding wheel (3) has a plurality of raised abrasive grains (32) evenly distributed on its outer periphery, and the plurality of abrasive grains (32) are arranged in an array; the abrasive grains (32) have a conical structure; S2. Fix the textured grinding wheel (3) on the milling machine spindle (11); S3. Fix the blank of the microchannel substrate (2) on the clamp (4) of the XY axis platform (5), so that the plane side of the bottom surface of the microchannel to be processed is close to the textured grinding wheel (3), and the textured grinding wheel (3) is tangent to the plane of the bottom surface of the microchannel to be processed. Move the blank to the starting position of one end of the microchannel to be processed through the XY axis platform (5). S4. Start the milling machine spindle (11) to rotate the textured grinding wheel (3) and move the textured grinding wheel (3) along the extension direction of the microchannel to be processed. The textured grinding wheel (3) is used to grind the rectangular slit (21) and its secondary texture structure (211) on the bottom surface in a single operation. S5. Deburring and cleaning the processed parts to obtain the required microchannel substrate (2). S6. Prepare a cover plate (6) and attach the cover plate (6) to the microchannel substrate (2) to obtain the desired microchannel heat exchanger with a bottom secondary texture.

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

3. The method for preparing a microchannel heat exchanger with a secondary bottom texture according to claim 1, characterized in that, The multiple microchannels are equidistant and parallel.

4. The method for preparing a microchannel heat exchanger with a secondary bottom texture according to claim 1, characterized in that: The material of the third-generation semiconductor of the microchannel substrate (2) is aluminum nitride or gallium nitride.

5. The method for preparing a microchannel heat exchanger with a secondary bottom texture according to claim 1, characterized in that, The vertices of the cones of each two adjacent conical structures are spaced 0.1 mm to 0.3 mm apart along the center line of the textured grinding wheel (3). The cone height of the conical structure is 0.1 mm to 0.2 mm, and the diameter of the cone base circle of the conical structure is 0.2 mm to 0.4 mm.

6. The method for preparing a microchannel heat exchanger with a secondary bottom texture according to claim 1, characterized in that, In step S2, multiple textured grinding wheels (3) are provided and the multiple textured grinding wheels (3) are arranged in parallel and fixed on the milling machine spindle (11) according to a set interval.

7. The method for preparing a microchannel heat exchanger with a secondary bottom texture according to claim 1, characterized in that, The textured grinding wheel (3) has a thickness of 0.5 mm to 3 mm and a diameter of 10 mm to 50 mm.

8. The method for preparing a microchannel heat exchanger with a secondary bottom texture according to claim 1, characterized in that, The textured grinding wheel (3) has a rotational speed of 1000 r / min to 4000 r / min, a feed rate of 0.075 m / min to 1.5 m / min, and a cutting depth of 0.5 mm to 3 mm.

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