A heat dissipation device for increasing heat dissipation area and its preparation method and application

Abstract

The present invention discloses a heat dissipation device for increasing the heat dissipation area, and its preparation method and application. The heat dissipation device comprises a heat sink and a heat dissipation water cooling pipe and a heat dissipation air cooling pipe inserted inside the heat sink. The surface of the heat sink is continuous convex grooves and concave grooves, which are alternately arranged at equal intervals, and a plurality of guide grooves are arranged at equal intervals on one side wall of the convex groove. The preparation method comprises: S1, heat sink preparation; S2, heat sink shaping; S3, heat dissipation air cooling pipe installation; S4, heat dissipation water cooling pipe installation. The heat dissipation device of the present invention can greatly increase the surface area of ​​the heat sink by providing the convex grooves and concave grooves, which can increase the surface area by about 30%, thereby improving the heat dissipation efficiency. The heat dissipation water cooling pipe and the heat dissipation air cooling pipe make the alternation of coolant and cold air, thereby maximizing the cooling and heat dissipation efficiency. The heat dissipation device is suitable for application in medical CT tube assemblies, thereby improving the heat dissipation efficiency of the ray window area of ​​the CT tube assembly during use, and extending the service life of the CT tube assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation devices, and in particular to a heat dissipation device with increased heat dissipation area, and a preparation method and application thereof. Background Art

[0002] A heat sink is a device that dissipates heat from heat-prone electronic components in electrical appliances. It is usually made of aluminum alloy, brass or bronze in the form of plates, sheets or multiple sheets. For example, the CPU in a computer uses a fairly large heat sink, as do the power tubes, line tubes in a TV, and the power amplifier tubes in an amplifier. Generally, a layer of thermal conductive silicone grease should be applied to the contact surface between the electronic components and the heat sink during use, so that the heat generated by the components can be more effectively transferred to the heat sink, and then dissipated to the surrounding air through the heat sink.

[0003] Copper has a good heat dissipation effect, but there are great deficiencies in its preparation and processing technology. The processing difficulty coefficient is high. It is difficult to meet the casting requirements or other process requirements using copper with special shapes. At the same time, the processing cost is also very high. It can only be completed by traditional mechanical processing methods. The heat dissipation effect of copper with conventional shapes is not ideal.

[0004] Heat sinks with good heat dissipation efficiency conduct heat through other media, usually water, gas, etc., but to achieve higher heat dissipation efficiency, it is necessary to improve and optimize the material, shape, and design to achieve a higher heat dissipation rate. Especially for heat sinks with odd shapes, it is necessary to increase the heat dissipation area to improve the heat dissipation rate. Such parts are very difficult to process and require high-precision molds or equipment to realize the shape of the parts. The surface quality of the heat dissipation parts themselves will also affect the heat dissipation effect. Therefore, the processing and preparation technology of such special-shaped heat dissipation parts is critical.

[0005] Patent CN110793374A discloses a high thermal conductivity heat sink for a radiator and a processing method thereof. The high thermal conductivity heat sink includes a bottom heat sink, on which a plurality of vertical plate heat sinks are arranged; each vertical plate heat sink is provided with an inverted U-shaped heat pipe, and the two ends of the inverted U-shaped heat pipe vertically downwardly pass through the two ends of the vertical plate heat sink and extend into the bottom heat sink. One end of the bottom of the inverted U-shaped heat pipe is connected to a coolant inlet pipe and the other end is connected to a coolant outlet pipe. Both side walls of each vertical plate heat sink are provided with graphite heat sinks, and heat-conducting fiber reinforced heat sinks are arranged outside the graphite heat sink. The processing method includes the following steps: S1, preparing graphite heat sinks; S2, preparing heat-conducting fiber reinforced heat sinks; S3, preparing bottom heat sinks and vertical plate heat sinks; S4, assembling vertical plate heat sinks, graphite heat sinks, and heat-conducting fiber reinforced heat sinks. The heat sink has better heat dissipation performance; the high thermal conductivity heat sink is easy to process and assemble, and is convenient for mass production. However, the heat dissipation effect is not good when applied to CT tube assemblies. Summary of the invention

[0006] In view of the above-mentioned problems, the present invention provides a heat dissipation device with increased heat dissipation area, and a preparation method and application thereof.

[0007] The technical solution of the present invention is:

[0008] A heat dissipation device for increasing the heat dissipation area comprises a heat dissipation fin and a heat dissipation water cooling pipe and a heat dissipation air cooling pipe inserted in the heat dissipation fin, the surface of the heat dissipation fin is continuous convex grooves and concave grooves, the convex grooves and concave grooves are alternately arranged at equal intervals, and a side wall of the convex groove is provided with a plurality of guide grooves at equal intervals;

[0009] The heat dissipation water cooling pipe is arranged at the inner bottom of the convex groove, and the heat dissipation water cooling pipe passes through the inner bottom of each convex groove in turn to form a Z-shaped loop. The heat dissipation air cooling pipe is arranged at the inner top of the groove, and the heat dissipation air cooling pipe passes through the inner top of each groove in turn to form a Z-shaped loop. The heat dissipation water cooling pipe and each bending point at both ends of the heat dissipation air cooling pipe are connected by a connecting column, the outer walls of the convex grooves on both sides of the guide groove are welded to the heat dissipation air cooling pipe, and the outer wall of the heat dissipation air cooling pipe is provided with a plurality of air outlets, and each of the air outlets corresponds to the position of each guide groove one by one.

[0010] Furthermore, the heat sink is a copper-tungsten alloy heat sink, and the high thermal conductivity of the copper-tungsten alloy is utilized to improve the heat dissipation efficiency of the heat sink.

[0011] Furthermore, the flow direction of the coolant in the heat dissipation water cooling pipe is opposite to the flow direction of the cold air in the heat dissipation air cooling pipe, so that the cooling and heat dissipation efficiency is improved to the greatest extent by alternating the coolant and the cold air.

[0012] Furthermore, a fixed block is provided at each of the upper and lower ends of the connecting column, and the two fixed blocks are fixedly connected to the heat dissipation water cooling pipe and the heat dissipation air cooling pipe respectively. A rotating shaft is rotatably provided between the two fixed blocks, and a plurality of heat dissipation fins are provided at equal intervals on the outer wall of the rotating shaft. The radius of the heat dissipation fins gradually decreases from the middle of the rotating shaft to the two ends of the rotating shaft, and the heat dissipation fins are made of the same material as the heat sink. The setting of the connecting column can not only enhance the stability of the heat dissipation water cooling pipe and the heat dissipation air cooling pipe, but also achieve the purpose of auxiliary heat dissipation through the rotation of the heat dissipation fins.

[0013] Furthermore, an air outlet slot is provided below the heat dissipation and cooling pipe at a position corresponding to the connection column, the angle of the air outlet slot along the heat dissipation and cooling pipe is 90°, and the extension direction of the air outlet slot corresponds to the side where the convex groove is located. The provision of the air outlet slot can not only provide ventilation for the inside of the convex groove, but also enable the heat dissipation fins to rotate, thereby enhancing the heat dissipation effect.

[0014] A method for preparing a heat dissipation device for increasing heat dissipation area as described in any one of the above, comprising the following steps:

[0015] S1. Heat sink preparation:

[0016] S1-1, powder ball milling: quantitatively weigh copper powder, tungsten powder and graphene powder, put them into a ball mill and mill them together to obtain a mixed powder with a particle size of 500nm-1μm;

[0017] S1-2, vacuum mixing: adding the mixed powder obtained in step S1-1 into a vacuum mixer, adding a wax-based binder, the wax-based binder accounting for 0.5-3% of the total mass of the mixed powder, evacuating the mixture and heating it to 80-90°C, stirring for 0.5-1h, and then using a twin-screw extruder to extrude the vacuum mixed powder into a prefabricated mold;

[0018] S1-3, vacuum sintering: placing the mold containing the mixed powder in step S1-2 into a vacuum melting furnace, first heating the mold to 550-650°C at a heating rate of 120-180°C / h for dewaxing for 2.5-3h, then heating the mold to 1120-1260°C at a heating rate of 100-140°C / h for sintering for 2-4h, maintaining the temperature and introducing argon gas to a pressure of 1-2MPa, continuing to keep the temperature for 0.5-1h, then naturally cooling the mold to room temperature to obtain a metal block, and demolding the metal block;

[0019] S1-4, CNC cutting: placing the metal block obtained in step S1-3 in a CNC planer, cutting the metal block into a thin sheet with a thickness of 0.2-0.3 mm, placing the thin sheet in a CNC milling machine, smoothing the surface of the thin sheet, and obtaining a copper-tungsten alloy heat sink with a thickness of 0.15±0.02 mm, a width of 8-10 cm, and a length of 16 cm, and then cutting the metal block into a thin sheet with a thickness of 0.1-0.2 mm, and then placing the thin sheet in a CNC milling machine, smoothing the surface of the thin sheet, and obtaining a heat sink with a thickness of 0.05±0.01 mm, and then cutting the heat sink into discs of different sizes and installing them on the rotating shaft;

[0020] S2. Heat sink shaping:

[0021] S2-1, heat treatment: heat treatment the copper-tungsten alloy heat sink obtained in step S1-4 at a temperature of 500-600° C. for 30 min;

[0022] S2-2, bending die: clamp the bending die on the flat-nose pliers, put the copper-tungsten alloy heat sink after the heat treatment in step S2-1 into the bending die along the length direction, place the die block in the slot of the bending die, and form a guide groove with a die pressing time of 10-15s. After one die pressing, bend the copper-tungsten alloy heat sink along the bottom of the guide groove to form a convex groove. Level the bent copper-tungsten alloy heat sink, and then place the next die block. Bend the copper-tungsten alloy heat sink along the bottom of the guide groove again to form a groove. Then use liquid nitrogen to quench the convex groove formed after the first bending. After the next convex groove is formed, quench the previous groove with liquid nitrogen. At the same time, avoid liquid nitrogen from interfering with the convex groove or groove being bent. The liquid nitrogen spray is sprayed synchronously at both ends of the convex groove or groove. The spray radius is 3-4mm, and the spray speed is 0.5-0.8m / s. The spray time is the same as the die pressing time. Repeat the above operation to complete the bending die pressing;

[0023] S3, heat dissipation and air cooling pipe installation: place the prefabricated heat dissipation and air cooling pipe on the inner top of the groove, weld the outer wall of the convex groove on both sides of the guide groove to the heat dissipation and air cooling pipe, and then weld and fix each connecting column to each bending part of the heat dissipation and air cooling pipe;

[0024] S4. Installation of heat dissipation water cooling pipes: placing the prefabricated heat dissipation water cooling pipes on the inner bottom of the convex groove, and welding and fixing the bending part of each heat dissipation water cooling pipe to the bottom of the corresponding connecting column to obtain a heat dissipation device.

[0025] Furthermore, in step S1-1, the mass ratio of copper powder, tungsten powder and graphene powder is 6-8: 2.5: 1. The performance of the heat sink can be improved by reasonably adjusting the ratio of copper powder, tungsten powder and graphene powder.

[0026] Furthermore, in terms of mass ratio, the wax-based binder in step S1-2 includes the following components:

[0027] Polyethylene wax: paraffin wax: high density polyethylene: stearic acid: ethylene-vinyl acetate copolymer: antioxidant = 35-40: 8-10: 12-15: 6-9: 3-4: 0.5-1;

[0028] The antioxidant is butylated hydroxytoluene, which ensures the mixing uniformity and strength of the mixed powder.

[0029] The application of a heat dissipation device for increasing the heat dissipation area as described in any one of the above items is applied to a heat dissipation system in a CT tube ray window area.

[0030] The beneficial effects of the present invention are:

[0031] (1) The heat dissipation device of the present invention can greatly increase the surface area of ​​the heat sink by about 30% through the provision of convex grooves and concave grooves, thereby improving the heat dissipation efficiency. The cooling liquid and the cold air are alternately circulated through the heat dissipation water cooling pipe and the heat dissipation air cooling pipe, thereby maximizing the cooling and heat dissipation efficiency. The heat dissipation device can also be directly used in the oil circuit, and is widely used with good heat dissipation effect.

[0032] (2) The heat sink of the heat dissipation device of the present invention has limited components, and the high thermal conductivity of copper-tungsten alloy is used to improve the heat dissipation efficiency of the heat sink. At the same time, the setting of the connecting column can not only enhance the stability of the heat dissipation water cooling pipe and the heat dissipation air cooling pipe, but also achieve the purpose of auxiliary heat dissipation through the rotation of the heat dissipation fins. The setting of the air outlet slot can not only provide ventilation to the inside of the convex slot, but also enable the heat dissipation fins to rotate, thereby enhancing the heat dissipation effect.

[0033] (3) In the heat dissipation device preparation method of the present invention, vacuum kneading, vacuum sintering and shaping of the heat sink can make the prepared heat sink higher in density and better in thermal conductivity. The component ratio of the wax-based binder ensures the mixing uniformity of the mixed powder and the strength of the heat sink.

[0034] (4) The heat dissipation device of the present invention is suitable for application in medical CT tube assemblies. It optimizes traditional heat dissipation parts, improves the heat dissipation efficiency of the radiation window area of ​​the CT tube assembly during use, optimizes the use environment of the CT tube assembly, and extends the service life of the CT tube assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall structure of the heat dissipation device of the present invention;

[0036] Figure 2 It is a schematic diagram of the connection structure between the heat dissipation air cooling pipe and the guide groove of the heat dissipation device of the present invention;

[0037] Figure 3 It is a schematic diagram of the structure of the connecting column of the heat dissipation device of the present invention;

[0038] Figure 4 It is a schematic diagram of the air outlet slot structure of the heat dissipation device of the present invention;

[0039] Figure 5 It is a process flow chart of the heat dissipation device preparation method of the present invention.

[0040] Among them, 1-heat sink, 2-heat dissipation water cooling pipe, 3-heat dissipation air cooling pipe, 31-air outlet, 32-air outlet slot, 4-convex slot, 5-groove, 6-guide slot, 7-connecting column, 71-fixing block, 72-rotating shaft, 73-heat dissipation fin. DETAILED DESCRIPTION

[0041] Example 1

[0042] like Figure 1 As shown, a heat dissipation device for increasing the heat dissipation area comprises a heat sink 1 and a heat dissipation water cooling tube 2 and a heat dissipation air cooling tube 3 inserted into the heat sink 1. The heat sink 1 is a copper-tungsten alloy heat sink. The surface of the heat sink 1 is provided with continuous convex grooves 4 and concave grooves 5. The convex grooves 4 and concave grooves 5 are alternately arranged at equal intervals. A plurality of guide grooves 6 are arranged at equal intervals on one side wall of the convex groove 4.

[0043] like Figure 1 , 2 As shown, the heat dissipation water cooling pipe 2 is arranged at the inner bottom of the convex groove 4, and the heat dissipation water cooling pipe 2 passes through the inner bottom of each convex groove 4 in sequence to form a Z-shaped loop. The heat dissipation air cooling pipe 3 is arranged at the inner top of the groove 5, and the heat dissipation air cooling pipe 3 passes through the inner top of each groove 5 in sequence to form a Z-shaped loop. The heat dissipation water cooling pipe 2 and the heat dissipation air cooling pipe 3 are connected at each bending point at both ends through a connecting column 7. The outer wall of the convex groove 4 on both sides of the guide groove 6 is welded to the heat dissipation air cooling pipe 3. The outer wall of the heat dissipation air cooling pipe 3 is provided with a plurality of air outlets 31, and each air outlet 31 corresponds to the position of each guide groove 6 one by one. The flow direction of the coolant inside the heat dissipation water cooling pipe 2 is opposite to the flow direction of the cold air inside the heat dissipation air cooling pipe 3.

[0044] like Figure 3 , 4 As shown, a fixed block 71 is respectively provided at the upper and lower ends of the connecting column 7, and the two fixed blocks 71 are fixedly connected to the heat dissipation water cooling tube 2 and the heat dissipation air cooling tube 3 respectively. A rotating shaft 72 is rotatably provided between the two fixed blocks 71, and a plurality of heat dissipation fins 73 are evenly spaced on the outer wall of the rotating shaft 72. The radius of the heat dissipation fins 73 gradually decreases from the middle of the rotating shaft 72 to the two ends of the rotating shaft 72. The heat dissipation fins 73 are made of the same material as the heat dissipation fin 1. An air outlet slot 32 is provided at a position corresponding to the connecting column 7 below the heat dissipation air cooling tube 3. The angle of the air outlet slot 32 along the heat dissipation air cooling tube 3 is 90°, and the extension direction of the air outlet slot 32 corresponds to the side where the convex groove 4 is located.

[0045] Example 2

[0046] This embodiment is based on the preparation method provided by the heat dissipation device in Embodiment 1, such as Figure 5 As shown, the following steps are included:

[0047] S1. Preparation of heat sink 1:

[0048] S1-1, powder ball milling: quantitatively weigh copper powder, tungsten powder and graphene powder and put them into a ball mill for ball milling to obtain a mixed powder with a particle size of 750 nm. The mass ratio of copper powder, tungsten powder and graphene powder is 7:2.5:1;

[0049] S1-2, vacuum mixing: add the mixed powder obtained in step S1-1 into a vacuum mixer, and add a wax-based binder at the same time, the wax-based binder accounts for 2% of the total mass of the mixed powder, evacuate and heat to 85°C, stir for 0.75h, and then use a twin-screw extruder to extrude the vacuum-mixed mixed powder into a prefabricated mold. The wax-based binder includes the following components by mass ratio:

[0050] Polyethylene wax: paraffin wax: high-density polyethylene: stearic acid: ethylene-vinyl acetate copolymer: antioxidant = 37:9:13:8:3:1;

[0051] The antioxidant was butylated hydroxytoluene;

[0052] S1-3, vacuum sintering: the mold containing the mixed powder in step S1-2 is placed in a vacuum melting furnace, first heated to 600°C at a heating rate of 160°C / h for dewaxing for 2.75h, then heated to 1200°C at a heating rate of 120°C / h for sintering for 3h, the temperature is maintained and argon is introduced to a pressure of 1.5MPa, and the temperature is kept for 0.75h, then naturally cooled to room temperature to obtain a metal block, which is demolded and taken out;

[0053] S1-4, CNC cutting: placing the metal block obtained in step S1-3 in a CNC planer, cutting the metal block into a thin sheet with a thickness of 0.25 mm, placing the thin sheet in a CNC milling machine, smoothing the surface of the thin sheet, and obtaining a copper-tungsten alloy heat sink with a thickness of 0.15±0.02 mm, a width of 9 cm, and a length of 16 cm, and then cutting the metal block into a thin sheet with a thickness of 0.15 mm, and then placing the thin sheet in a CNC milling machine, smoothing the surface of the thin sheet, and obtaining a heat sink fin 73 with a thickness of 0.05±0.01 mm, and then cutting the heat sink fin 73 into discs of different sizes, and installing them on the rotating shaft 72;

[0054] S2, heat sink 1 shaping:

[0055] S2-1, heat treatment: heat treatment the copper-tungsten alloy heat sink 1 obtained in step S1-4 at a temperature of 550° C. for 30 min;

[0056] S2-2, bending die: clamp the bending die on the flat-nose pliers, put the copper-tungsten alloy heat sink 1 after the heat treatment in step S2-1 into the bending die along the length direction, place the die block in the slot of the bending die, and the die forms a guide groove 6. The die pressing time is 12s. After one die pressing, bend the copper-tungsten alloy heat sink 1 along the bottom of the guide groove 6 to form a convex groove 4. Level the bent copper-tungsten alloy heat sink 1, and then place the next die block. Bend the copper-tungsten alloy heat sink 1 along the bottom of the guide groove 6 again to form a groove 5. Then use liquid nitrogen to quench the convex groove 4 formed after the first bending. After the next convex groove 4 is formed, the previous groove 5 is quenched with liquid nitrogen. At the same time, avoid liquid nitrogen from interfering with the convex groove 4 or groove 5 being bent. The liquid nitrogen spray is sprayed synchronously at both ends of the convex groove 4 or groove 5. The spray radius is 3.5mm, the spray speed is 0.6m / s, and the spray time is the same as the die pressing time. Repeat the above operation to complete the bending die pressing;

[0057] S3, installation of heat dissipation and air cooling pipe 3: place the prefabricated heat dissipation and air cooling pipe 3 on the inner top of the groove 5, weld the outer wall of the convex groove 4 on both sides of the guide groove 6 to the heat dissipation and air cooling pipe 3, and then weld and fix each connecting column 7 to each bending part of the heat dissipation and air cooling pipe 3;

[0058] S4, installation of the heat dissipation water cooling pipe 2: placing the prefabricated heat dissipation water cooling pipe 2 on the inner bottom of the convex groove 4, and welding and fixing the bending part of each heat dissipation water cooling pipe 2 to the bottom of the corresponding connecting column 7 to obtain a heat dissipation device.

[0059] Example 3

[0060] This embodiment is based on the application of the heat dissipation device provided in Embodiment 1, and applies it to the heat dissipation system of the CT tube ray window area.

[0061] Example 4

[0062] This embodiment is basically the same as Embodiment 2, except that the composition ratio of the mixed powder is different.

[0063] S1-1. Powder ball milling: Copper powder, tungsten powder and graphene powder are quantitatively weighed and put into a ball mill for ball milling to obtain a mixed powder with a particle size of 1 μm. The mass ratio of copper powder, tungsten powder and graphene powder is 6:2.5:1.

[0064] Example 5

[0065] This embodiment is basically the same as Embodiment 2, except that the composition ratio of the mixed powder is different.

[0066] S1-1. Powder ball milling: Copper powder, tungsten powder and graphene powder are weighed quantitatively and put into a ball mill for ball milling to obtain a mixed powder with a particle size of 500 nm. The mass ratio of copper powder, tungsten powder and graphene powder is 8:2.5:1.

[0067] Example 6

[0068] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S1-2 and vacuum mixing are different.

[0069] S1-2, vacuum mixing: add the mixed powder obtained in step S1-1 into a vacuum mixer, and add a wax-based binder at the same time, the wax-based binder accounts for 0.5% of the total mass of the mixed powder, evacuate and heat to 80°C, stir for 0.5h, and then use a twin-screw extruder to extrude the vacuum-mixed mixed powder into a prefabricated mold. The wax-based binder includes the following components by mass ratio:

[0070] Polyethylene wax: paraffin: high-density polyethylene: stearic acid: ethylene-vinyl acetate copolymer: antioxidant = 35: 8: 12: 6: 3: 0.5;

[0071] The antioxidant is butylated hydroxytoluene.

[0072] Example 7

[0073] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S1-2 and vacuum mixing are different.

[0074] S1-2, vacuum mixing: add the mixed powder obtained in step S1-1 into a vacuum mixer, and add a wax-based binder at the same time, the wax-based binder accounts for 3% of the total mass of the mixed powder, evacuate and heat to 90°C, stir for 1 hour, and then use a twin-screw extruder to extrude the vacuum-mixed mixed powder into a prefabricated mold. The wax-based binder includes the following components by mass ratio:

[0075] Polyethylene wax: paraffin wax: high-density polyethylene: stearic acid: ethylene-vinyl acetate copolymer: antioxidant = 40:10:15:9:4:1;

[0076] The antioxidant is butylated hydroxytoluene.

[0077] Example 8

[0078] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S1-3 and vacuum sintering are different.

[0079] S1-3. Vacuum sintering: Place the mold containing the mixed powder in step S1-2 into a vacuum melting furnace, first heat it to 550°C at a heating rate of 120°C / h for dewaxing for 2.5h, then heat it to 1120°C at a heating rate of 100°C / h for sintering for 2h, maintain the temperature and introduce argon gas to a pressure of 1MPa, continue to keep warm for 0.5h, then naturally cool to room temperature to obtain a metal block, and demold and take it out.

[0080] Example 9

[0081] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S1-3 and vacuum sintering are different.

[0082] S1-3. Vacuum sintering: Place the mold containing the mixed powder in step S1-2 into a vacuum melting furnace, first heat it to 650°C at a heating rate of 180°C / h for dewaxing for 3 hours, then heat it to 1260°C at a heating rate of 140°C / h for sintering for 4 hours, maintain the temperature and introduce argon gas to a pressure of 2 MPa, continue to keep warm for 1 hour, then naturally cool to room temperature to obtain a metal block, and demold and take it out.

[0083] Example 10

[0084] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S1-4 and CNC cutting are different.

[0085] S1-4, CNC cutting: Place the metal block obtained in step S1-3 in a CNC planer, cut the metal block into a thin sheet with a thickness of 0.2 mm, place the thin sheet in a CNC milling machine, smooth the surface of the thin sheet, and obtain a copper-tungsten alloy heat sink with a thickness of 0.15±0.02 mm, a width of 8 cm, and a length of 16 cm. Cut the metal block into a thin sheet with a thickness of 0.1 mm, place the thin sheet in a CNC milling machine, smooth the surface of the thin sheet, and obtain a heat sink fin 73 with a thickness of 0.05±0.01 mm. Cut the heat sink fin 73 into discs of different sizes and install them on the rotating shaft 72.

[0086] Embodiment 11

[0087] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S1-4 and CNC cutting are different.

[0088] S1-4, CNC cutting: Place the metal block obtained in step S1-3 in a CNC planer, cut the metal block into a thin sheet with a thickness of 0.3 mm, place the thin sheet in a CNC milling machine, smooth the surface of the thin sheet, and obtain a copper-tungsten alloy heat sink with a thickness of 0.15±0.02 mm, a width of 10 cm, and a length of 16 cm. Cut the metal block into a thin sheet with a thickness of 0.2 mm, place the thin sheet in a CNC milling machine, smooth the surface of the thin sheet, and obtain a heat sink fin 73 with a thickness of 0.05±0.01 mm. Cut the heat sink fin 73 into discs of different sizes and install them on the rotating shaft 72.

[0089] Example 12

[0090] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S2-1 and heat treatment are different.

[0091] S2-1, heat treatment: heat-treat the copper-tungsten alloy heat sink 1 obtained in step S1-4 at a heat treatment temperature of 500° C. for 30 minutes.

[0092] Embodiment 13

[0093] This embodiment is basically the same as Embodiment 2, except that the process parameters of step S2-1 and heat treatment are different.

[0094] S2-1, heat treatment: heat treatment is performed on the copper-tungsten alloy heat sink 1 obtained in step S1-4, the heat treatment temperature is 600° C., and the heat treatment time is 30 min.

[0095] Embodiment 14

[0096] This embodiment is basically the same as Embodiment 2, except that the process parameters of the bending and laminating step S2-2 are different.

[0097] S2-2, bending die: clamp the bending die on the flat-nose pliers, put the copper-tungsten alloy heat sink 1 after the heat treatment in step S2-1 into the bending die along the length direction, place the die block in the slot of the bending die, and form a guide groove 6 with a die pressing time of 10s. After one die pressing, bend the copper-tungsten alloy heat sink 1 along the bottom of the guide groove 6 to form a convex groove 4. Level the bent copper-tungsten alloy heat sink 1, and then place the next die block. Bend the copper-tungsten alloy heat sink 1 along the bottom of the guide groove 6 again to form a groove 5. Then use liquid nitrogen to quench the convex groove 4 formed after the first bending. After the next convex groove 4 is formed, quench the previous groove 5 with liquid nitrogen, and avoid liquid nitrogen from interfering with the convex groove 4 or groove 5 being bent. The liquid nitrogen spray is sprayed synchronously at both ends of the convex groove 4 or groove 5. The spray radius is 3mm, the spray speed is 0.5m / s, and the spray time is the same as the die pressing time. Repeat the above operation to complete the bending die.

[0098] Embodiment 15

[0099] This embodiment is basically the same as Embodiment 2, except that the process parameters of the bending and laminating step S2-2 are different.

[0100] S2-2, bending die: clamp the bending die on the flat-nose pliers, put the copper-tungsten alloy heat sink 1 after the heat treatment in step S2-1 into the bending die along the length direction, place the die block in the slot of the bending die, and form a guide groove 6 with a die pressing time of 15s. After one die pressing, bend the copper-tungsten alloy heat sink 1 along the bottom of the guide groove 6 to form a convex groove 4. Level the bent copper-tungsten alloy heat sink 1, and then place the next die block. Bend the copper-tungsten alloy heat sink 1 along the bottom of the guide groove 6 again to form a groove 5. Then use liquid nitrogen to quench the convex groove 4 formed after the first bending. After the next convex groove 4 is formed, quench the previous groove 5 with liquid nitrogen, and avoid liquid nitrogen from interfering with the convex groove 4 or groove 5 being bent. The liquid nitrogen spray is sprayed synchronously at both ends of the convex groove 4 or groove 5. The spray radius is 4mm, the spray speed is 0.8m / s, and the spray time is the same as the die pressing time. Repeat the above operation to complete the bending die.

[0101] Experimental example

[0102] The thermal conductivity of the heat sink 1 in the five groups of embodiments selected by the present invention is measured. At the same time, the heat sink 1 is applied to the heat dissipation system of the radiation window area of ​​the CT tube assembly. The temperature of the radiation window area of ​​the CT tube using the heat sink 1 of the present invention and the conventional commercially available heat sink in the comparative example is measured, and the periods are compared. The experimental results are shown in Tables 1 and 2.

[0103] Table 1 Thermal conductivity of heat sinks of Examples 2, 4, 5, 6, and 7

[0104]

[0105] It can be seen from the data in Table 1 that the thermal conductivity of the heat sink in Example 2 is slightly better than that in Examples 4 and 5. Therefore, the thermal conductivity of the mixed powder component ratio in Example 2 is the best; the difference in thermal conductivity between Example 2 and Examples 6 and 7 is not large, and the binder component ratio in Example 7 is the best; the parameter adjustments in Examples 8-15 are all conventional adjustments within the parameter range given in the present invention, and no detailed comparison is made here.

[0106] Table 2 CT tube window temperature during heat dissipation in Example 2 and Comparative Example

[0107]

[0108] It can be seen from the data in Table 2 that the temperature of the CT tube ray window area can be effectively reduced by applying the heat sink 1 of Example 2 of the present invention, and the heat dissipation performance is improved to a certain extent compared with conventional heat sinks available on the market.

Claims

1. A heat dissipation device for increasing heat dissipation area, characterized in that: The heat sink (1) comprises a heat sink (1) and a heat sink water cooling pipe (2) and a heat sink air cooling pipe (3) inserted into the heat sink (1); the surface of the heat sink (1) is provided with continuous convex grooves (4) and concave grooves (5); the convex grooves (4) and concave grooves (5) are alternately arranged at equal intervals; and a plurality of guide grooves (6) are arranged at equal intervals on one side wall of the convex groove (4); The heat dissipation water cooling pipe (2) is arranged at the inner bottom of the convex groove (4), and the heat dissipation water cooling pipe (2) passes through the inner bottom of each convex groove (4) in sequence to form a Z-shaped loop. The heat dissipation air cooling pipe (3) is arranged at the inner top of the groove (5), and the heat dissipation air cooling pipe (3) passes through the inner top of each groove (5) in sequence to form a Z-shaped loop. Each bending point at both ends of the heat dissipation water cooling pipe (2) and the heat dissipation air cooling pipe (3) is connected by a connecting column (7). The outer wall of the convex groove (4) on both sides of the guide groove (6) is welded to the heat dissipation air cooling pipe (3). The outer wall of the heat dissipation air cooling pipe (3) is provided with a plurality of air outlets (31), and each of the air outlets (31) corresponds to the position of each guide groove (6) one by one. A fixed block (71) is respectively provided at the upper and lower ends of the connecting column (7), and the two fixed blocks (71) are respectively fixedly connected to the heat dissipation water cooling pipe (2) and the heat dissipation air cooling pipe (3). A rotating shaft (72) is rotatably provided between the two fixed blocks (71), and a plurality of heat dissipation fins (73) are evenly spaced on the outer wall of the rotating shaft (72). The radius of the heat dissipation fins (73) gradually decreases from the middle of the rotating shaft (72) to the two ends of the rotating shaft (72), and the heat dissipation fins (73) are made of the same material as the heat dissipation fins (1).

2. A heat dissipation device for increasing heat dissipation area according to claim 1, characterized in that: The heat sink (1) is a copper-tungsten alloy heat sink.

3. A heat dissipation device for increasing heat dissipation area according to claim 1, characterized in that: The flow direction of the coolant inside the heat dissipation water cooling pipe (2) is opposite to the flow direction of the cold air inside the heat dissipation air cooling pipe (3).

4. A heat dissipation device for increasing heat dissipation area according to claim 1, characterized in that: An air outlet slot (32) is provided below the heat dissipation and air cooling pipe (3) at a position corresponding to the connecting column (7); the angle of the air outlet slot (32) along the heat dissipation and air cooling pipe (3) is 90°, and the extension direction of the air outlet slot (32) corresponds to the side where the convex groove (4) is located.

5. A method for preparing a heat dissipation device with increased heat dissipation area according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Preparation of heat sink (1): S1-1, powder ball milling: quantitatively weigh copper powder, tungsten powder and graphene powder, put them into a ball mill and mill them together to obtain a mixed powder with a particle size of 500nm-1μm; S1-2, vacuum mixing: adding the mixed powder obtained in step S1-1 into a vacuum mixer, adding a wax-based binder, the wax-based binder accounting for 0.5-3% of the total mass of the mixed powder, evacuating the mixture and heating it to 80-90°C, stirring for 0.5-1h, and then using a twin-screw extruder to extrude the vacuum mixed powder into a prefabricated mold; S1-3, vacuum sintering: placing the mold containing the mixed powder in step S1-2 into a vacuum melting furnace, first heating the mold to 550-650°C at a heating rate of 120-180°C / h for dewaxing for 2.5-3h, then heating the mold to 1120-1260°C at a heating rate of 100-140°C / h for sintering for 2-4h, maintaining the temperature and introducing argon gas to a pressure of 1-2MPa, continuing to keep the temperature for 0.5-1h, then naturally cooling the mold to room temperature to obtain a metal block, and demolding the metal block; S1-4, CNC cutting: placing the metal block obtained in step S1-3 in a CNC planer, cutting the metal block into a thin sheet with a thickness of 0.2-0.3 mm, then placing the thin sheet in a CNC milling machine, smoothing the surface of the thin sheet, and obtaining a copper-tungsten alloy heat sink with a thickness of 0.15±0.02 mm, a width of 8-10 cm, and a length of 16 cm, then cutting the metal block into a thin sheet with a thickness of 0.1-0.2 mm, then placing the thin sheet in a CNC milling machine, smoothing the surface of the thin sheet, and obtaining a heat sink (73) with a thickness of 0.05±0.01 mm, and then cutting the heat sink (73) into discs of different sizes and installing them on the rotating shaft (72); S2. Heat sink (1) shaping: S2-1, heat treatment: heat treating the copper-tungsten alloy heat sink (1) obtained in step S1-4 at a temperature of 500-600° C. for 30 min; S2-2, bending die: clamp the bending die on a flat-nose pliers, place the copper-tungsten alloy heat sink (1) after heat treatment in step S2-1 into the bending die along the length direction, place the die block in the slot of the bending die, and form a guide groove (6) with a die pressing time of 10-15 seconds. After one die pressing, bend the copper-tungsten alloy heat sink (1) along the bottom of the guide groove (6) to form a convex groove (4), level the bent copper-tungsten alloy heat sink (1), and then place the next die block, and again bend the copper-tungsten alloy heat sink (1) along the guide groove (6). The bottom is bent to form a groove (5), and then the convex groove (4) formed after the first bending is quenched with liquid nitrogen. After the next convex groove (4) is formed, the previous groove (5) is quenched with liquid nitrogen, and at the same time, the liquid nitrogen is prevented from interfering with the convex groove (4) or the groove (5) being bent. The liquid nitrogen is sprayed synchronously at both ends of the convex groove (4) or the groove (5), and the spray radius is 3-4 mm. The spray speed is 0.5-0.8 m / s. The time of one spray is the same as the time of one die pressing. Repeat the above operation to complete the bending die pressing; S3, installation of the heat dissipation air cooling pipe (3): placing the prefabricated heat dissipation air cooling pipe (3) on the inner top of the groove (5), welding the outer wall of the convex groove (4) on both sides of the guide groove (6) to the heat dissipation air cooling pipe (3), and then welding and fixing each connecting column (7) to each bending part of the heat dissipation air cooling pipe (3); S4, installation of heat dissipation water cooling pipe (2): placing the prefabricated heat dissipation water cooling pipe (2) on the inner bottom of the convex groove (4), and welding and fixing the bending part of each heat dissipation water cooling pipe (2) to the bottom of the corresponding connecting column (7) to obtain a heat dissipation device.

6. The method for preparing a heat dissipation device with increased heat dissipation area according to claim 5, characterized in that: In the step S1-1, the mass ratio of copper powder, tungsten powder and graphene powder is 6-8:2.5:

1.

7. The method for preparing a heat dissipation device with increased heat dissipation area according to claim 5, characterized in that: In terms of mass ratio, the wax-based binder in step S1-2 includes the following components: Polyethylene wax: paraffin wax: high density polyethylene: stearic acid: ethylene-vinyl acetate copolymer: antioxidant = 35-40: 8-10: 12-15: 6-9: 3-4: 0.5-1; The antioxidant is butylated hydroxytoluene.

8. Application of a heat dissipation device for increasing heat dissipation area according to any one of claims 1 to 4, characterized in that: The heat dissipation device is applied to the heat dissipation system in the ray window area of ​​the CT tube.

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