Preparation method and application of directional graphene heat dissipation material for air compressor cylinder

Abstract

The application discloses a preparation method of a directional graphene heat dissipation material for an air compressor cylinder body, and comprises the following steps: S1, carbon fibers are taken, and an oxidized graphene layer is formed on the surface of the carbon fibers through a multistage oxidized graphene microdrop spraying mechanism; S2, high-temperature reduction is performed to form a graphene layer on the surface of the carbon fibers; S3, aluminum paste is sprayed on the surface of the carbon fibers to form an aluminum layer; S4, sintering is performed to form a carbon fiber / graphene / aluminum directional heat dissipation material; S5, the cooled carbon fibers are woven to form a directional heat dissipation core body; and S6, the directional heat dissipation core body is taken as a matrix, and an aluminum liquid is poured and formed into the cylinder body. After the carbon fiber bundle is arranged with multistage directional graphene films through the three-stage oxidized graphene microdrop spraying mechanism, the carbon fiber / graphene / aluminum heat conduction material is prepared, and the three-dimensional directional heat conduction core body is formed after being woven. After the three-dimensional directional heat conduction core body is integrally formed with the cylinder body, the heat conduction coefficient can be increased by more than 5 times. The heat conduction performance of the air compressor cylinder body is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of air compressor technology, and in particular relates to the preparation method and application of oriented graphene heat dissipation material for air compressor cylinders. Background Technology

[0002] An air compressor, also called an air pressurizer, is a device used to compress gas. It is the main component of an air source system, converting the mechanical energy of a prime mover (usually an electric motor) into gas pressure energy; it is the device that generates compressed air. The main compression work of an air compressor is performed by the compressor head. The cylinder assembly, driven by the electric motor, compresses the air. During the air compression process, the cylinder assembly generates a significant amount of heat.

[0003] To address the heat dissipation issue of the cylinder block assembly, CN110878744B discloses an air compressor head with a baffle tube. This baffle tube guides the airflow, directing the airflow from the cooling fan to the gaps between the cooling fins, thus improving heat dissipation. However, the biggest problem with this structure is that the compressor head continuously heats up during air compression, causing the air entering the head to be instantly heated. This means the air exiting the baffle tube is already at a high temperature, resulting in ineffective heat dissipation. Even with a cooling unit added inside the baffle tube, the heat dissipation effect decreases after prolonged standby. Furthermore, an air compressor disclosed in CN107313923B also suffers from the same problem.

[0004] Therefore, it is essential to improve the heat dissipation performance of the cylinder itself. Most existing cylinders are made using aluminum injection molding, and aluminum has a thermal conductivity of approximately 210 W / (m·K), which is insufficient to match the rate of temperature rise. Currently, researchers are actively searching for new high-performance thermally conductive materials, with graphene as a prime example. These novel two-dimensional crystalline materials, due to their single-atom-thickness two-dimensional crystal structure and unique physical properties, have become a research focus in recent years. Graphene, in particular, possesses outstanding thermal conductivity (5000 W / (m·K)) and an exceptionally large specific surface area (2630 m² / g), along with excellent processing properties for use on solid surfaces, making it an ideal heat dissipation material. However, regarding the heat dissipation applications of graphene, research on its preparation methods and application techniques is still in a rapid development stage. How to fully and rationally utilize graphene's high thermal conductivity and successfully apply it to the field of heat dissipation remains a pressing technical challenge. In the existing technology, most graphene heat dissipation materials are graphene heat dissipation films. Since graphene is a two-dimensional structure, the heat dissipation method can only diffuse the heat emitted from the surface of the object to the surrounding materials in a horizontal manner, which weakens the heat dissipation effect of the material to a certain extent. In addition, since graphene has a very large specific surface area, it is easy to agglomerate. If graphene agglomerates during preparation, it will greatly reduce the performance of the material. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing and applying oriented graphene heat dissipation material for air compressor cylinders, so as to solve the problems mentioned in the background art.

[0006] To solve this technical problem, the technical solution of the present invention is as follows:

[0007] A method for preparing oriented graphene heat dissipation material for air compressor cylinders includes the following steps:

[0008] S1: Take carbon fiber and attach a graphene oxide layer to the surface of the carbon fiber through a multi-stage graphene oxide microdroplet jetting mechanism;

[0009] S2: The graphene oxide layer on the surface of carbon fiber is reduced at high temperature to form a graphene layer on the surface of carbon fiber.

[0010] S3: Aluminum paste is sprayed onto the surface of the carbon fiber obtained in step S2 using an aluminum paste spraying device to form an aluminum layer;

[0011] S4: The carbon fiber obtained in step S3 is sintered so that the outer aluminum layer cross-links and forms a carbon fiber / graphene / aluminum directional heat dissipation material after sintering.

[0012] S5: The cooled carbon fiber is woven to form a directional heat dissipation core;

[0013] S6: The cylinder body is formed by casting molten aluminum and using a directional heat dissipation core as the base.

[0014] Preferably, the multi-stage graphene oxide microdroplet ejection mechanism includes a reaction chamber through which carbon fibers pass. Multi-stage graphene oxide microdroplet ejection units are arranged sequentially on opposite sides of the reaction chamber. Each graphene oxide microdroplet ejection unit includes a microdroplet forming module disposed on the reaction chamber. Each microdroplet forming module is connected to an independent microdroplet forming control unit. The microdroplet forming control unit includes a high-pressure gas source inlet device and an intermittent microdroplet liquid inlet device. The microdroplet forming module contains several regularly arranged droplet forming cavities, which are vertically connected. A high-pressure gas flow inlet is connected to the upper part of each cavity, which is connected to the high-pressure gas source inlet device. A liquid outlet is located at the lower part of each cavity, communicating with the reaction chamber. Each droplet forming cavity is also connected to a microdroplet inlet, which is connected to the intermittent microdroplet liquid inlet device.

[0015] Preferably, it includes three levels of graphene oxide microdroplet emitting units, namely a primary graphene oxide microdroplet emitting unit, a secondary graphene oxide microdroplet emitting unit, and a tertiary graphene oxide microdroplet emitting unit. The primary, secondary, and tertiary graphene oxide microdroplet emitting units are arranged in a straight line on the outer wall of the reaction chamber. Inside the reaction chamber, the primary, secondary, and tertiary graphene oxide emitting units correspond to the primary, secondary, and tertiary graphene oxide emitting units to form a first graphene oxide film forming cavity, a second graphene oxide film forming cavity, and a third graphene oxide film forming cavity.

[0016] Preferably, in step 1, the method for forming a graphene oxide layer on the carbon fiber surface includes the following steps:

[0017] S11: Prepare a graphene oxide solution and continuously vibrate the graphene oxide using an ultrasonic oscillation device;

[0018] A graphene oxide dispersion is formed;

[0019] S12: In the primary graphene oxide microdroplet emission unit, graphene oxide dispersion is introduced into the droplet forming cavity through an intermittent liquid feeding mechanism; at the same time, carbon fibers are transported to the first graphene oxide film forming cavity of the reaction chamber;

[0020] S13: The droplet forming cavity forms uniform microdroplets from the graphene oxide dispersion;

[0021] S14: High-pressure airflow ejects micro-droplets from the liquid outlet;

[0022] S15: After the microdroplets emitted from both sides collide with the carbon fiber, graphene oxide adheres to the carbon fiber to form the first graphene oxide layer.

[0023] S16: The carbon fiber continues to be fed into the second graphene oxide film forming cavity;

[0024] S17: When the distance between the top of the first graphene oxide film layer and the top surface of the second graphene oxide film layer forming cavity is S1, the primary graphene oxide microdroplet emission unit and the secondary graphene oxide microdroplet emission unit simultaneously eject graphene oxide microdroplets to superimpose the first graphene oxide layer and form the second graphene oxide layer below the first graphene oxide layer.

[0025] S18: The carbon fiber continues to be transported to the third graphene oxide film forming cavity. When the distance between the top of the first graphene oxide layer and the top surface of the third graphene oxide film forming cavity is S2, the primary graphene oxide microdroplet emission unit, the secondary graphene oxide microdroplet emission unit, and the tertiary graphene oxide microdroplet emission unit simultaneously eject graphene oxide microdroplets to superimpose the first graphene oxide layer and the second graphene oxide layer, and simultaneously form the third graphene oxide layer below the second graphene oxide layer.

[0026] S19: The carbon fiber output reaction chamber corresponding to the first graphene oxide layer, and the carbon fiber segment corresponding to the second graphene oxide layer are stacked for the third time in the third graphene oxide film forming chamber. This process continues to complete the stacking of the carbon fiber in each region using the three graphene oxide film layers.

[0027] This invention separates a graphene oxide solution into microdroplets and then attaches it to carbon fibers. This controls the aggregation of the graphene oxide solution before attachment and simultaneously prevents the aggregation of graphene oxide particles on the carbon fiber surface. This results in the formation of a single-layer or few-layer graphene oxide film on the carbon fiber surface.

[0028] Preferably, the diameter of the carbon fiber is 2mm.

[0029] Preferably, the directional heat dissipation core includes several interlocking hollow cylindrical grids woven from carbon fiber / graphene / aluminum directional heat dissipation material, forming outwardly diffused planar annular heat dissipation channels and longitudinal heat dissipation channels. The grids are radially connected to each other by carbon fiber / graphene / aluminum directional heat dissipation material to form radial heat dissipation channels.

[0030] Preferably, each hollow columnar grid forms a filling cavity between itself and the radially arranged carbon fiber / graphene / aluminum heat dissipation material, and molten aluminum is poured into the filling cavity, which solidifies to form the cylinder body.

[0031] The present invention forms planar heat dissipation channels, longitudinal heat dissipation channels, and radial heat dissipation channels in the cylinder body according to the cylinder body contour, so that the heat of the cylinder body can be quickly transferred to the outer surface of the cylinder body, achieving efficient heat dissipation.

[0032] Preferably, after molding, the outer surface of the directional heat dissipation core is on the same plane as the outer surface of the cylinder, and the inner surface is on the same plane as the inner surface of the cylinder.

[0033] Because the directional heat dissipation core and the inner surface of the cylinder are on the same plane as the inner wall of the cylinder, the heat generated by the piston and the inner wall is quickly conducted on the directional heat dissipation core. Furthermore, since the outer surface and the outer wall are on the same plane, the heat on the directional heat dissipation core is directly conducted to the outer wall of the cylinder, thus achieving efficient heat conduction.

[0034] Preferably, the spacing between the hollow cylindrical grids is 1.5 mm.

[0035] Preferably, the vertical spacing between the radially arranged carbon fiber / graphene / aluminum directional heat dissipation materials is 2.5 mm.

[0036] Preferably, the intermittent liquid inlet mechanism includes a flexible liquid storage bag disposed within an ultrasonic oscillation device, with the outlet of the flexible liquid storage bag connected to a droplet forming cavity; it also includes two extrusion cylinders disposed on both sides of the flexible liquid storage bag; the extrusion cylinders extrude the flexible liquid storage bag, causing the graphene oxide solution inside the flexible liquid storage bag to be squeezed into the droplet forming cavity.

[0037] The present invention also aims to provide a carbon fiber / graphene / aluminum directional heat dissipation material prepared by the above method.

[0038] To solve this technical problem, the technical solution of the present invention is to apply the carbon fiber / graphene / aluminum directional heat dissipation material of the present invention to the heat dissipation of the air compressor cylinder.

[0039] The beneficial effects of the present invention, as described above, are:

[0040] This invention uses a three-stage graphene oxide microdroplet jetting mechanism to arrange carbon fiber bundles into multi-stage oriented graphene films, thereby producing a carbon fiber / graphene / aluminum thermal conductive material. This material is then woven together to form a three-dimensional oriented thermal conductive core. When integrally formed with the cylinder body, its thermal conductivity can be increased by more than 5 times, thus greatly improving the thermal conductivity of the air compressor cylinder body. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the production equipment in this invention;

[0042] Figure 2 This is a schematic diagram of the cross-sectional structure of the microdroplet forming module in this invention;

[0043] Figure 3 This is a schematic diagram of the droplet forming cavity structure in this invention;

[0044] Figure 4 This is a schematic diagram of the directional heat dissipation core in this invention. Detailed Implementation

[0045] like Figure 1-4 As shown, in order to further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0046] Example 1

[0047] A method for preparing oriented graphene heat dissipation material for air compressor cylinders includes the following steps:

[0048] S1: Take carbon fiber with a diameter of 1mm. A graphene oxide layer is formed on the surface of the carbon fiber using a multi-stage graphene oxide microdroplet ejection mechanism. The multi-stage graphene oxide microdroplet ejection mechanism includes a reaction chamber 1 through which the carbon fiber passes. Multi-stage graphene oxide microdroplet launching units 2 are arranged sequentially on opposite sides of the reaction chamber. Each graphene oxide microdroplet launching unit includes a microdroplet forming module 3 mounted on the reaction chamber. Each microdroplet forming module is connected to an independent microdroplet forming control unit. The microdroplet forming control unit includes a high-pressure gas source inlet device 4 and an intermittent microdroplet liquid inlet device 5. The microdroplet forming module contains several regularly arranged droplet forming cavities 6 with an inner diameter of 5mm. The droplet forming cavities are vertically connected, with a high-pressure airflow inlet 7 connected to the upper part of the cavity and the high-pressure airflow inlet connected to the high-pressure gas source inlet device 4. A liquid outlet 9 is located at the lower part of the cavity and is connected to the reaction chamber. The droplet forming cavity is also connected to a microdroplet inlet, which is connected to an intermittent microdroplet inlet device 5. This embodiment includes a three-stage graphene oxide microdroplet emitting unit, namely a primary graphene oxide microdroplet emitting unit, a secondary graphene oxide microdroplet emitting unit, and a tertiary graphene oxide microdroplet emitting unit. The primary, secondary, and tertiary graphene oxide microdroplet emitting units are arranged in a straight line on the outer wall of the reaction cavity. Inside the reaction cavity, the primary, secondary, and tertiary graphene oxide emitting units correspond to the primary, secondary, and tertiary graphene oxide emitting units to form a first graphene oxide film forming cavity, a second graphene oxide film forming cavity, and a third graphene oxide film forming cavity. Specifically, the method for forming a graphene oxide layer on the carbon fiber surface includes the following steps: S11: Add the graphene oxide prepared by the Hummers method to DMF and ultrasonically disperse it 2.After 5 hours of peeling, uniformly dispersed graphene oxide / DMF is obtained. An ultrasonic oscillation device is used to continuously oscillate the dispersed graphene oxide solution to form a stable dispersed graphene oxide dispersion. S12: In the primary graphene oxide microdroplet emission unit, the graphene oxide dispersion is input into the droplet forming cavity via an intermittent liquid inlet mechanism. Simultaneously, carbon fibers are transported to the first graphene oxide film forming cavity of the reaction chamber. The intermittent liquid inlet mechanism includes a flexible storage bag 11 housed within the ultrasonic oscillation device. The outlet of the flexible storage bag is connected to the microdroplet inlet of the droplet forming cavity. It also includes two extrusion cylinders 12 positioned on both sides of the flexible storage bag. The extrusion cylinders extrude the flexible storage bag, causing the graphene oxide solution within the bag to be forced into the droplet forming cavity. S13: The droplet forming chamber forms uniform microdroplets from the graphene oxide dispersion. A high-pressure airflow enters the inlet, propelling the microdroplets out of the outlet. S14: After the microdroplets from opposite sides collide with the carbon fiber, graphene oxide adheres to the carbon fiber, forming the first graphene oxide layer. S15: The carbon fiber continues to be transported to the second graphene oxide film forming chamber. S16: When the distance between the top of the first graphene oxide film layer and the top surface of the second graphene oxide film forming chamber is S1 (the value of S1 is determined by the carbon fiber transport speed V1, the distance between the outlet and the carbon fiber S0, and the droplet ejection speed V2; the calculation method can be S1 = V1S0 / V2), the primary graphene oxide microdroplet emitting unit and the secondary graphene oxide microdroplet emitting unit... The graphene microdroplet emission unit simultaneously ejects graphene oxide microdroplets, superimposing the first graphene oxide layer and forming a second graphene oxide layer below it; S17: Carbon fibers continue to be transported to the third graphene oxide film forming cavity. When the distance between the top of the first graphene oxide layer and the top surface of the third graphene oxide film forming cavity is S2 (S2 is calculated in the same way as S1), the primary, secondary, and tertiary graphene microdroplet emission units simultaneously eject graphene oxide microdroplets, superimposing the first and second graphene oxide layers and forming a third graphene oxide layer below it; S18: The carbon fibers corresponding to the first graphene oxide layer are transported... S1: The carbon fiber segments corresponding to the second graphene oxide layer are stacked for the third time in the third graphene oxide film forming chamber, and this process is continued to complete the stacking of the three graphene oxide film layers in each region; S2: The carbon fibers treated in step 1 are passed into a reducing atmosphere furnace with two reduction temperature sections, 600 degrees Celsius and 1000 degrees Celsius, to reduce the graphene oxide layer on the carbon fiber surface at high temperature and form a graphene layer on the carbon fiber surface; S3: Aluminum paste is sprayed onto the surface of the carbon fibers obtained in step S2 using an aluminum paste spraying device to form an aluminum layer; S4: The carbon fibers obtained in step S3 are sintered at a sintering temperature of 660 degrees Celsius, so that the outer aluminum layer is cross-linked and formed after sintering, and the thickness of the aluminum layer is 0.1-0.3mm, forming a carbon fiber / graphene / aluminum directional heat dissipation material; S5: weaving the cooled carbon fiber to form a directional heat dissipation core; S6: using the directional heat dissipation core as the base, and casting the cylinder body with molten aluminum. The directional heat dissipation core comprises several interlocking hollow cylindrical grids 13 woven from carbon fiber / graphene / aluminum directional heat dissipation material, forming outwardly diffused planar annular heat dissipation channels and longitudinal heat dissipation channels. The grids are radially connected by the carbon fiber / graphene / aluminum directional heat dissipation material, forming radial heat dissipation channels 14. A filling cavity 15 is formed between each hollow cylindrical grid and the radially arranged carbon fiber / graphene / aluminum heat dissipation material. Molten aluminum is poured into the filling cavity, and after solidification, it forms the cylinder body. The cylinder body has an inner diameter of 18 cm and a wall thickness of 1.5 cm. After molding, the outer surface of the directional heat dissipation core is on the same plane as the outer surface of the cylinder body, and the inner surface is on the same plane as the inner surface of the cylinder body. The spacing L1 between the hollow cylindrical grids is 1 mm, and the vertical spacing L2 between the radially arranged carbon fiber / graphene / aluminum directional heat dissipation materials is 1.5 mm.

[0049] Example 2

[0050] The difference from Example 1 is that the diameter of the carbon fiber in step S1 is 1.5 mm;

[0051] Example 3

[0052] The difference from Example 1 is that the diameter of the carbon fiber in step S1 is 2 mm;

[0053] Example 4

[0054] The difference from Example 1 is that the diameter of the carbon fiber in step S1 is 2.5 mm;

[0055] Example 5

[0056] The difference from Example 1 is that the diameter of the carbon fiber in step S1 is 3 mm;

[0057] Example 6

[0058] The difference from Example 1 is that the diameter of the carbon fiber in step S1 is 3.5 mm;

[0059] Example 7

[0060] The difference from Example 3 is that the spacing L1 between the hollow cylindrical grids is 1.2 mm;

[0061] Example 8

[0062] The difference from Example 3 is that the spacing L1 between the hollow cylindrical grids is 1.5 mm;

[0063] Example 9

[0064] The difference from Example 3 is that the spacing L1 between the hollow cylindrical grids is 1.8 mm;

[0065] Example 10

[0066] The difference from Example 3 is that the spacing L1 between the hollow cylindrical grids is 2.0 mm;

[0067] Example 11

[0068] The difference from Example 8 is that the vertical spacing L2 between the radially arranged carbon fiber / graphene / aluminum oriented heat dissipation materials is 2mm;

[0069] Example 12

[0070] The difference from Example 8 is that the vertical spacing L2 between the radially arranged carbon fiber / graphene / aluminum oriented heat dissipation materials is 2.5 mm;

[0071] Example 13

[0072] The difference from Example 8 is that the vertical spacing L2 between the radially arranged carbon fiber / graphene / aluminum oriented heat dissipation materials is 3mm;

[0073] Example 14

[0074] The difference from Example 8 is that the vertical spacing L2 between the radially arranged carbon fiber / graphene / aluminum oriented heat dissipation materials is 4 mm.

[0075] Example 15

[0076] The difference from Example 12 is that the inner diameter of the droplet forming cavity is 8 mm;

[0077] Example 16

[0078] The difference from Example 12 is that the inner diameter of the droplet forming cavity is 10 mm;

[0079] Example 17

[0080] The difference from Example 12 is that the inner diameter of the droplet forming cavity is 12 mm;

[0081] Example 18

[0082] The difference from Example 12 is that the inner diameter of the droplet forming cavity is 15 mm;

[0083] Example 19

[0084] The difference from Example 16 is that a primary graphene oxide microdroplet emitting unit is used to form a graphene oxide film on the carbon fiber surface.

[0085] Example 20

[0086] The difference from Example 16 is that a graphene oxide film layer is formed on the carbon fiber surface using a secondary graphene oxide microdroplet emitting unit.

[0087] Example 21

[0088] The difference from Example 16 is that a graphene oxide film layer is formed on the carbon fiber surface using a four-level graphene oxide microdroplet emitting unit.

[0089] Example 22

[0090] The difference from Example 16 is that a graphene oxide film layer is formed on the carbon fiber surface using a five-level graphene oxide microdroplet emitting unit.

[0091] Comparative Example 1

[0092] The cylinder body is formed by direct casting of molten aluminum. The inner diameter of the cylinder body is 18cm and the thickness of the cylinder wall is 1.5cm.

[0093] Comparative Example 2

[0094] The immersion method is used directly, and the specific steps are as follows:

[0095] A1: Graphene oxide prepared by the Hummers method was added to DMF, ultrasonically dispersed for 2.5 h, and then exfoliated to obtain a uniformly dispersed graphene oxide / DMF solution. The dispersed graphene oxide solution was continuously agitated using an ultrasonic oscillator to form a stable graphene oxide dispersion. A2: Carbon fibers with a diameter of 1.5 mm were taken and immersed in the stable graphene oxide dispersion solution, stirred, and removed after 2.5 h. A3: After reduction, the cooled carbon fibers were woven to form a heat dissipation core. A4: The heat dissipation core was used as the base material, and a cylinder was formed by casting molten aluminum.

[0096] Comparative Example 3

[0097] The immersion method is used directly, and the specific steps are as follows:

[0098] A1: Graphene oxide prepared by the Hummers method was added to DMF, ultrasonically dispersed for 2.5 h, and then exfoliated to obtain a uniformly dispersed graphene oxide / DMF solution. The dispersed graphene oxide solution was continuously agitated using an ultrasonic oscillator to form a stable graphene oxide dispersion. A2: Carbon fibers with a diameter of 1.5 mm were immersed in the stable graphene oxide dispersion, stirred, and removed after 2.5 h. A3: After reduction, aluminum paste was attached and sintered. A4: The cooled carbon fibers were woven to form a heat dissipation core. A5: The heat dissipation core was used as the base material, and a cylinder was cast with molten aluminum.

[0099] Experimental results: Thermal conductivity of Examples 1-22 and Comparative Examples 1-3 was tested along the carbon fiber length alignment direction; thermal conductivity was tested using a C-THERM TCI instrument according to ASTM D7984 standard.

[0100] The test results are shown in Table 1.

[0101] Table 1

[0102]

[0103] Table 1 shows that after arranging carbon fiber bundles into multi-level oriented graphene films using a three-level graphene oxide microdroplet jetting mechanism, a carbon fiber / graphene / aluminum thermal conductive material is prepared. This material is then woven to form a three-dimensional oriented thermal conductive core, which, when integrally molded with the cylinder body, increases the thermal conductivity by more than 5 times, significantly improving the thermal conductivity of the air compressor cylinder. Comparing Examples 1 to 6, it is evident that as the diameter of the carbon fiber increases, the thermal conductivity of the cylinder gradually increases and then stabilizes. This demonstrates that when the diameter of the carbon fiber is 2 mm, the cylinder's thermal conductivity is optimal under this condition. The main reason for this is the increased diameter of the carbon fiber. As its surface area increases, graphene monoliths are less likely to stack on its surface. Comparing Examples 3 and 7-10, it can be seen that as the spacing between the hollow cylindrical grids increases, the thermal conductivity of the cylinder first tends to level off and then decreases, proving that the thermal conductivity of the cylinder is optimal when the spacing between the hollow cylindrical grids is 1.5 mm. Comparing Examples 8 and 11-14, it can be seen that as the vertical spacing between the radially arranged carbon fiber / graphene / aluminum oriented heat dissipation materials increases, the thermal conductivity of the cylinder first tends to level off and then decreases, proving that the optimal vertical spacing between the radially arranged carbon fiber / graphene / aluminum oriented heat dissipation materials is 2.5 mm. Comparing Examples 12 and 15-18, it can be seen that as the inner diameter of the droplet forming cavity increases, the thermal conductivity of the cylinder first increases and then gradually flattens out. The thermal conductivity of the cylinder is highest when the inner diameter of the droplet forming cavity on the front is 10 mm, that is, when the diameter of the formed droplets is 10 mm. Comparing Examples 16 and 19-22, the thermal conductivity of the four-stage and five-stage graphene oxide microdroplet spraying mechanisms did not increase significantly compared with the three-stage graphene oxide microdroplet spraying mechanism; in fact, it decreased. The reason is that the four-stage and five-stage graphene oxide microdroplet spraying mechanisms cause the graphene sheets on the carbon fiber surface to stack, while the one-stage and two-stage graphene oxide microdroplet spraying mechanisms cause the graphene layer on the carbon fiber surface to have breaks, thus affecting the thermal conductivity. Therefore, the three-stage graphene oxide microdroplet spraying mechanism is the best for directional alignment of carbon fibers.

[0104] Comparing Comparative Example 1 and Comparative Example 2, it can be seen that the thermal conductivity of the cylinder can be increased by 50% by integrally forming a heat dissipation core of graphene / carbon fiber weaving inside the cylinder. Comparing Comparative Example 2 and Comparative Example 3, it can be seen that sintering after spraying aluminum paste onto the carbon fiber with attached graphene can significantly improve the thermal conductivity of the cylinder. This indicates that the aluminum layer can better protect the monolayer of graphene on the surface of the carbon fiber, preventing it from peeling off and causing graphene layer breakage, which would affect its heat dissipation effect. Comparing Comparative Example 3 and Example 1, it can be seen that the multi-stage graphene oxide microdroplet spraying mechanism can better oriented the graphene to the carbon fiber to improve its thermal conductivity.

[0105] The present invention also aims to provide a carbon fiber / graphene / aluminum directional heat dissipation material prepared by the above method.

[0106] The present invention also aims to provide an application of the carbon fiber / graphene / aluminum directional heat dissipation material prepared by the above method.

Claims

1. A method for preparing oriented graphene heat dissipation material for air compressor cylinders, characterized in that: Includes the following steps: S1: Take carbon fiber and attach a graphene oxide layer to the surface of the carbon fiber through a multi-stage graphene oxide microdroplet jetting mechanism; S2: The graphene oxide layer on the surface of carbon fiber is reduced at high temperature to form a graphene layer on the surface of carbon fiber. S3: Aluminum paste is sprayed onto the surface of the carbon fiber obtained in step S2 using an aluminum paste spraying device to form an aluminum layer; S4: The carbon fiber obtained in step S3 is sintered so that the outer aluminum layer cross-links and forms a carbon fiber / graphene / aluminum directional heat dissipation material after sintering. S5: The cooled carbon fiber is woven to form a directional heat dissipation core; S6: The cylinder body is formed by casting molten aluminum and using a directional heat dissipation core as the base. The multi-stage graphene oxide microdroplet ejection mechanism includes a reaction chamber through which carbon fibers pass. Multi-stage graphene oxide microdroplet ejection units are arranged sequentially on opposite sides of the reaction chamber. Each graphene oxide microdroplet ejection unit includes a microdroplet forming module mounted on the reaction chamber. Each microdroplet forming module is connected to an independent microdroplet forming control unit. The microdroplet forming control unit includes a high-pressure gas source inlet device and an intermittent microdroplet liquid inlet device. The microdroplet forming module contains several regularly arranged droplet forming cavities, which are vertically connected. The upper part of each cavity is connected to a high-pressure gas flow inlet, which is connected to the high-pressure gas source inlet device. The lower part of each cavity has a liquid outlet that communicates with the reaction chamber. Each droplet forming cavity is also connected to a microdroplet inlet, which is connected to the intermittent microdroplet liquid inlet device. It includes three levels of graphene oxide microdroplet emission units, namely a primary graphene oxide microdroplet emission unit, a secondary graphene oxide microdroplet emission unit, and a tertiary graphene oxide microdroplet emission unit. The primary, secondary, and tertiary graphene oxide microdroplet emission units are arranged in a straight line on the outer wall of the reaction chamber. Inside the reaction chamber, the primary, secondary, and tertiary graphene oxide emission units correspond to the primary, secondary, and tertiary graphene oxide emission units to form a first graphene oxide film forming cavity, a second graphene oxide film forming cavity, and a third graphene oxide film forming cavity. In step 1, the method for forming a graphene oxide layer on the surface of carbon fibers includes the following steps: S11: Prepare a graphene oxide solution and use an ultrasonic oscillation device to continuously oscillate the graphene oxide to form a graphene oxide dispersion. S12: In the primary graphene oxide microdroplet emission unit, graphene oxide dispersion is introduced into the droplet forming cavity through an intermittent liquid feeding mechanism; at the same time, carbon fibers are transported to the first graphene oxide film forming cavity of the reaction chamber; S13: The droplet forming cavity forms uniform microdroplets from the graphene oxide dispersion; S14: High-pressure airflow ejects micro-droplets from the liquid outlet; S15: After the microdroplets emitted from both sides collide with the carbon fiber, graphene oxide adheres to the carbon fiber to form the first graphene oxide layer. S16: The carbon fiber continues to be fed into the second graphene oxide film forming cavity; S17: When the distance between the top of the first graphene oxide film layer and the top surface of the second graphene oxide film layer forming cavity is S1, the primary graphene oxide microdroplet emission unit and the secondary graphene oxide microdroplet emission unit simultaneously eject graphene oxide microdroplets to superimpose the first graphene oxide layer and form the second graphene oxide layer below the first graphene oxide layer. S18: The carbon fiber continues to be transported to the third graphene oxide film forming cavity. When the distance between the top of the first graphene oxide layer and the top surface of the third graphene oxide film forming cavity is S2, the primary graphene oxide microdroplet emission unit, the secondary graphene oxide microdroplet emission unit, and the tertiary graphene oxide microdroplet emission unit simultaneously eject graphene oxide microdroplets to superimpose the first graphene oxide layer and the second graphene oxide layer, and simultaneously form the third graphene oxide layer below the second graphene oxide layer. S19: The carbon fiber output reaction chamber corresponding to the first graphene oxide layer, and the carbon fiber segment corresponding to the second graphene oxide layer are stacked for the third time in the third graphene oxide film forming chamber. This process continues to complete the stacking of the carbon fiber in each region using the three graphene oxide film layers.

2. The method for preparing oriented graphene heat dissipation material for air compressor cylinders according to claim 1, characterized in that: The carbon fiber has a diameter of 2mm.

3. The method for preparing the oriented graphene heat dissipation material for air compressor cylinders according to claim 1, characterized in that: The directional heat dissipation core includes several interlocking hollow cylindrical grids woven from carbon fiber / graphene / aluminum directional heat dissipation material, forming outwardly diffused planar annular heat dissipation channels and longitudinal heat dissipation channels. The grids are radially connected by carbon fiber / graphene / aluminum directional heat dissipation material to form radial heat dissipation channels.

4. The method for preparing oriented graphene heat dissipation material for air compressor cylinders according to claim 1, characterized in that: Each hollow columnar grid and the radially arranged carbon fiber / graphene / aluminum heat dissipation material form a filling cavity, in which molten aluminum is poured and solidified to form the cylinder body.

5. The method for preparing oriented graphene heat dissipation material for air compressor cylinders according to claim 1, characterized in that: After molding, the outer surface of the directional heat dissipation core is on the same plane as the outer surface of the cylinder, and the inner surface is on the same plane as the inner surface of the cylinder.

6. The method for preparing oriented graphene heat dissipation material for air compressor cylinders according to claim 1, characterized in that: The radially arranged carbon fiber / graphene / aluminum directional heat dissipation materials are spaced 2.5mm apart vertically.

7. The method for preparing oriented graphene heat dissipation material for air compressor cylinders according to claim 1, characterized in that: The intermittent liquid inlet mechanism includes a flexible liquid storage bag disposed within an ultrasonic oscillation device, with the outlet of the flexible liquid storage bag connected to a droplet forming cavity; it also includes two extrusion cylinders disposed on both sides of the flexible liquid storage bag; the extrusion cylinders extrude the flexible liquid storage bag, causing the graphene oxide solution inside the flexible liquid storage bag to be squeezed into the droplet forming cavity.

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