Heat dissipation enhanced current sensor shell

Abstract

The invention provides a heat dissipation enhanced current sensor shell, which comprises an inner shell and an outer shell, a wire through hole is formed in the inner shell, a mounting cavity for placing a PCB (Printed Circuit Board) is formed between the inner shell and the outer shell, a plurality of copper-aluminum composite heat pipes are arranged on the outer shell along the wire direction, and the heat pipes are filled with nanofluids. The outer shell is further provided with a copper nail array penetrating through the heat pipe, the density of the copper nail array is higher than 36 / cm < 2 >, the copper nail array makes contact with the PCB, the heat pipe is provided with a fin array distributed in the direction of the electric wire, all fin units of the fin array are forked by 90 degrees, each fin unit is provided with a honeycomb unit, shape memory alloy sheets are embedded in all honeycomb holes of the honeycomb units, and the shape memory alloy sheets are arranged in the shape memory alloy sheets. A top cover covering the heat pipes and the fin array is arranged on the outer shell, an air inlet and an air outlet are formed in the two ends, in the wire direction, of the top cover respectively, the air inlet is provided with a Venturi tube, and the air outlet is provided with a Helmholtz resonant cavity.

Description

Technical Field

[0001] The present invention relates to the technical field of current sensors, and particularly to a heat dissipation enhanced current sensor housing. Background Art

[0002] The heat dissipation problem of current sensors is mainly caused by internal power consumption and material properties. When current passes through the internal conductor of a current sensor, Joule heat is generated, and its heat generation is proportional to the square of the current and the resistance value. In high-current scenarios, even low-resistance manganin materials will still generate significant heat. Especially in open-loop Hall sensors, eddy currents are generated when high-frequency current passes through the magnetic core, resulting in a sharp increase in the magnetic core temperature.

[0003] The reason for the heat dissipation defect of current sensors is that some sensor designs do not fully consider the heat dissipation requirements. For example, the heat sink area is small, and the heat-conducting material is not properly selected, resulting in the inability to quickly export heat. More fatally, the existing heat dissipation holes adopt a linear array layout, inducing the "through wind" effect. According to PIV tests, 80% of the air flow does not flow through the heating elements and directly passes through the housing. Summary of the Invention

[0004] The present invention aims to solve the above technical problems and provides a heat dissipation enhanced current sensor housing.

[0005] The technical solution of the present invention is a heat dissipation enhanced current sensor housing, which includes an inner housing and an outer housing. The inner housing forms a wire perforation, and an installation cavity for placing a PCB board is formed between the inner housing and the outer housing. The outer housing is provided with a plurality of copper-aluminum composite heat pipes along the wire direction. The heat pipes are filled with nanofluid. The outer housing is also provided with a copper nail array that penetrates the heat pipes and has a density higher than 36 pieces / cm 2 The copper nail array is in contact with the PCB board. The heat pipes are provided with a fin array distributed along the wire direction. Each fin unit of the fin array is bifurcated at 90°, and each fin unit is provided with a honeycomb unit. Shape memory alloy thin sheets are embedded in each honeycomb hole of the honeycomb unit. The alloy thin sheets unfold to form a spiral flow guiding surface at 55°C. The outer housing is provided with a top cover covering the heat pipes and the fin array. The two ends of the top cover along the wire direction respectively form an air inlet and an air outlet. The bifurcation direction of the fin unit faces the air outlet. The air inlet is provided with a Venturi tube, and the air outlet is provided with a Helmholtz resonance cavity. The end of the Helmholtz resonance cavity is provided with a gradually expanding opening.

[0006] As an embodiment, 3 heat pipes are provided, and the diameter of each heat pipe is 6 mm.

[0007] As an embodiment, the nanofluid is a mixture composed of 15% alumina nanoparticles and 85% ethanol.

[0008] As an implementation manner, the spacing between adjacent fin units gradually increases along the direction from the air inlet to the air outlet.

[0009] As an implementation manner, the edge of the fin unit is serrated fractal.

[0010] As an implementation manner, the honeycomb holes of the honeycomb unit are non-uniformly arranged, and the density of the honeycomb holes in the core area is greater than that in the edge area.

[0011] As an implementation manner, a thermal conductive silicone grease layer is provided at the connection between the bottom of the heat pipe and the copper nail array.

[0012] As an implementation manner, the alloy thin sheet is a nickel-titanium shape memory alloy thin sheet, and the thickness of the alloy thin sheet is 0.1 mm.

[0013] As an implementation manner, the Helmholtz resonance cavity includes a cuboid cavity and a neck passage connecting the cuboid cavity and the air outlet, and the gradually expanding opening is connected to the cuboid cavity.

[0014] The beneficial effect of the present invention compared with the prior art is that for this heat dissipation enhanced current sensor housing, the heat transfer path is redesigned, and a three-stage conduction path of heat generating element → copper nail array → heat pipe → fin array is established, and a convection path of acceleration section → honeycomb maze → resonance cavity is also established. The cooperative heat dissipation effect of the conduction path and the convection path is reflected in that when the air flow passes through the fin array between the air inlet and the air outlet, due to the 90° bifurcation of the fin units, the fin array forms a fishbone shape. Therefore, when the air flow contacts one branch of the fin unit, it will turn to the branch of the adjacent fin unit. The air flow direction between the two fin arrays is a zigzag line, avoiding the phenomenon of "draught". And when the temperature is higher than 55 °C, the honeycomb unit starts to work. The zigzag line direction of the air flow is changed. Because of the formation of the spiral guide surface, part of the air flow can pass through the honeycomb holes. A considerable number of honeycomb holes are located on the convection path, forming a honeycomb maze effect, which greatly increases the effective contact area between the air and the fin array. Therefore, this heat dissipation enhanced current sensor housing forms an adaptive thermal management system through the cooperative heat dissipation of heat conduction and convection, and in cooperation with the dynamically adjustable structure, and has significantly enhanced heat dissipation performance compared with the traditional current sensor housing. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of the heat dissipation enhanced current sensor housing provided by the embodiment of the present invention;

[0016] Figure 2 It is a first partial cross-sectional view of the heat dissipation enhanced current sensor housing provided by the embodiment of the present invention;

[0017] Figure 3 This is the second partial cross-sectional view of the heat dissipation enhanced current sensor housing provided by the embodiment of the present invention;

[0018] Figure 4 This is the third partial cross-sectional view of the heat dissipation enhanced current sensor housing provided by the embodiment of the present invention;

[0019] Figure 5 This is the schematic structural view of the fin unit and the honeycomb unit provided by the embodiment of the present invention.

[0020] In the figure: 1, inner housing; 2, outer housing; 3, wire perforation; 4, installation cavity; 5, heat pipe; 6, copper nail array; 7, fin array; 8, fin unit; 9, honeycomb unit; 10, honeycomb hole; 11, alloy thin sheet; 12, spiral flow guiding surface; 13, top cover; 14, air inlet; 15, air outlet; 16, Venturi tube; 17, Helmholtz resonance cavity; 18, gradually expanding opening; 19, cuboid cavity; 20, neck channel. Specific embodiments

[0021] The following will clearly and completely describe the above and other embodiments and advantages of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only partial embodiments of the present invention, rather than all embodiments.

[0022] In one embodiment, as Figures 1 to 5 shown.

[0023] The heat dissipation enhanced current sensor housing provided by this embodiment includes an inner housing 1 and an outer housing 2. The inner housing 1 forms a wire perforation 3. An installation cavity 4 for placing the PCB board is formed between the inner housing 1 and the outer housing 2. The outer housing 2 is provided with a number of copper-aluminum composite heat pipes 5 along the wire direction. The heat pipes 5 are filled with nanofluid. The outer housing 2 is also provided with a copper nail array 6 that penetrates through the heat pipes 5 and has a density higher than 36 / cm 2 . The copper nail array 6 is in contact with the PCB board. The heat pipes 5 are provided with a fin array 7 distributed along the wire direction. Each fin unit 8 of the fin array 7 is bifurcated at 90°. And each fin unit 8 is provided with a honeycomb unit 9. Shape memory alloy thin sheets 11 are embedded in each honeycomb hole 10 of the honeycomb unit 9. The alloy thin sheets 11 unfold to form a spiral flow guiding surface 12 at 55°C. The outer housing 2 is provided with a top cover 13 covering the heat pipes 5 and the fin array 7. The two ends of the top cover 13 along the wire direction respectively form an air inlet 14 and an air outlet 15. The bifurcation direction of the fin unit 8 faces the air outlet 15. The air inlet 14 is provided with a Venturi tube 16. The air outlet 15 is provided with a Helmholtz resonance cavity 17. The end of the Helmholtz resonance cavity 17 is provided with a gradually expanding opening 18.

[0024] In this embodiment, the heat dissipation enhanced current sensor housing has redesigned the heat transfer path. Since the copper pin array 6 is in contact with the PCB board, a three-stage conduction path of heat generating element → copper pin array 6 → heat pipe 5 → fin array 7 is established. The copper-aluminum composite heat pipe 5 serves as the main artery channel and forms a fishbone shape with the fin arrays 7 extending on both sides. Also, due to the setting of the Venturi tube 16 and the Helmholtz resonance cavity 17, a convection path of acceleration section → honeycomb maze → resonance cavity is established. The synergistic heat dissipation effect of the conduction path and the convection path is reflected in that when the air flow passes through the fin array 7 between the air inlet 14 and the air outlet 15, due to the 90° bifurcation of the fin unit 8, the fin array 7 forms a fishbone shape. Therefore, when the air flow contacts one branch of the fin unit 8, it will deflect to the adjacent branch of the other fin unit 8. The air flow direction between the two fin arrays 7 is in a zigzag line, avoiding the phenomenon of "through wind". And when the temperature is higher than 55 °C, the honeycomb unit 9 starts to function. As Figure 5 shown, the alloy thin sheet 11 unfolds to form a spiral guide surface 12 at 55 °C. Therefore, when the temperature is higher than 55 °C, the zigzag line direction of the aforementioned air flow is changed. Because of the formation of the spiral guide surface 12, part of the air flow can pass through the honeycomb holes 10. A considerable number of honeycomb holes 10 are located on the convection path, forming a honeycomb maze effect, greatly increasing the effective contact area between the air and the fin array 7. The set Helmholtz resonance cavity 17 can absorb the high-order harmonics generated by the air flow through the resonance cavity, reduce the air flow pulsation energy, and improve the air flow stability.

[0025] Therefore, the heat dissipation enhanced current sensor housing forms an adaptive thermal management system through the synergistic heat dissipation of heat conduction and convection, combined with a dynamically adjustable structure. Compared with the traditional current sensor housing, the heat dissipation performance is significantly enhanced.

[0026] In one embodiment, there are 3 heat pipes 5 in the heat dissipation enhanced current sensor housing, and the diameter of each heat pipe 5 is 6 mm.

[0027] In this embodiment, the 3 heat pipes (central + symmetric on both sides) cover the heat sources in the long axis direction of the housing, splitting the concentrated heat flow into three independent transfer paths, avoiding overloading of a single heat pipe and ensuring the uniformity of temperature distribution. The 6 mm diameter matches the height limit of the housing.

[0028] In one embodiment, the nanofluid of the heat dissipation enhanced current sensor housing is a mixture composed of 15% alumina nanoparticles and 85% ethanol.

[0029] In this embodiment, the copper-aluminum composite heat pipe 5 uses nanoparticles to enhance heat transfer, and the thermal conductivity can be increased by more than 50% compared with pure ethanol. The 15% concentration can achieve a better balance between fluidity and enhanced heat conduction, because too high a concentration will cause particle agglomeration, and too low a concentration will result in insufficient heat transfer improvement.

[0030] In one embodiment, as Figure 3 shown.

[0031] For the heat dissipation enhanced current sensor housing provided in this embodiment, the spacing between adjacent fin units 8 gradually increases along the direction from the air inlet 14 to the air outlet 15.

[0032] In this embodiment, such a setting realizes the flow velocity gradient control. The small spacing in the inlet section increases the shear force of the flow velocity boundary layer, improves the heat transfer coefficient near the wall surface, and the large spacing in the outlet section reduces the flow resistance and avoids the accumulation of pressure drop. The volume of the air expands due to the increase in temperature along the convection path, and the increase in the spacing compensates for the required cross-sectional area of the air flow to prevent local overheating.

[0033] In one embodiment, as Figure 5 shown.

[0034] For the heat dissipation enhanced current sensor housing provided in this embodiment, the edges of the fin units 8 are serrated fractal.

[0035] In this embodiment, such a setting can disrupt the boundary layer. The serrated sharp corners periodically disturb the air flow, forcefully peel off the laminar boundary layer, and increase the Nusselt number of the heat transfer surface. Each serration generates two pairs of counter-rotating micro-vortices, increasing the vortex density and strengthening the heat transfer at the gas-solid interface. The fractal structure scatters the concentrated heat flow into multi-level branch paths, reducing the standard deviation of the fin surface temperature and eliminating local hot spots.

[0036] In one embodiment, as Figure 5 shown.

[0037] For the heat dissipation enhanced current sensor housing provided in this embodiment, the honeycomb holes 10 of each honeycomb unit 9 are non-uniformly arranged, and the density of the honeycomb holes 10 in the core area is greater than that in the edge area.

[0038] In this embodiment, such a setting can achieve the matching of heat flux density. The high-density honeycombs in the core area increase the heat transfer area, compensate for the heat flux density in the heat generation concentrated area, and the low density in the edge area avoids ineffective pressure drop. And the density gradient forms a tapered flow channel, prolonging the residence time of the air flow and strengthening the convective heat transfer.

[0039] In one embodiment, a thermal grease layer is provided at the connection of the bottom of the heat pipe 5 to the copper nail array 6.

[0040] In this embodiment, the thermal grease layer has a certain viscosity, which not only plays a role in connecting the copper nail array 6 and the PCB board, but also plays a role in heat conduction.

[0041] In one embodiment, the alloy sheet 11 is a nickel-titanium shape memory alloy sheet, and the thickness of the alloy sheet 11 is 0.1 mm.

[0042] In this embodiment, the nickel-titanium shape memory alloy sheet is filled in the honeycomb holes 10 and almost blocks the honeycomb holes 10 when not unfolded. When unfolded, a spiral flow guiding surface 12 can be formed to change the direction of the air flow.

[0043] In one embodiment, the Helmholtz resonance cavity 17 of the heat dissipation enhanced current sensor housing includes a cuboid cavity 19 and a neck passage 20 connecting the cuboid cavity 19 and the air outlet 15, and a gradually expanding opening 18 is connected to the cuboid cavity 19.

[0044] In this embodiment, a horn-shaped gradually expanding opening 18 is provided at the end of the Helmholtz resonance cavity 17. After the air flow is modulated by the resonance cavity, it is discharged from the housing in a laminar flow form through this opening and is directly communicated with the external environment. A flow guiding lip extends from the outer edge of the opening to avoid backflow disturbance.

[0045] The specific embodiments described above further elaborate on the invention purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. In particular, for those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A heat dissipation enhanced current sensor housing, characterized in that It includes an inner housing and an outer housing. The inner housing forms a wire perforation, and an installation cavity for placing a PCB board is formed between the inner housing and the outer housing. A plurality of copper-aluminum composite heat pipes along the wire direction are provided on the outer housing. The heat pipes are filled with nanofluid. A copper nail array with a density higher than 36 / cm 2 is provided on the outer housing, and the copper nail array is in contact with the PCB board. A fin array distributed along the wire direction is provided on the heat pipe. Each fin unit of the fin array is bifurcated at 90°, and each fin unit is provided with a honeycomb unit. Shape memory alloy thin sheets are embedded in each honeycomb hole of the honeycomb unit. The alloy thin sheets unfold at 55°C to form a spiral flow guiding surface. A top cover covering the heat pipe and the fin array is provided on the outer housing. An air inlet and an air outlet are respectively formed at both ends of the top cover along the wire direction. The bifurcation direction of the fin unit faces the air outlet. A Venturi tube is provided at the air inlet, and a Helmholtz resonance cavity is provided at the air outlet. A gradually expanding opening is provided at the end of the Helmholtz resonance cavity.

2. The heat dissipation enhanced current sensor housing according to claim 1, wherein The heat pipes are provided in three numbers, and the diameter of each heat pipe is 6 mm.

3. The heat dissipation enhanced current sensor housing according to claim 1, characterized in that, The nanofluid is a mixture composed of 15% alumina nanoparticles and 85% ethanol.

4. The heat dissipation enhanced current sensor housing according to claim 1, wherein The spacing between adjacent fin units gradually increases along the direction from the air inlet to the air outlet.

5. The heat dissipation enhanced current sensor housing according to claim 4, wherein The edge of the fin unit is serrated fractal.

6. The heat dissipation enhanced current sensor housing according to claim 1, characterized in that, The honeycomb holes of the honeycomb unit are non-uniformly arranged, and the honeycomb hole density in the core area is greater than that in the edge area.

7. The heat dissipation enhanced current sensor housing according to claim 1, characterized in that, A thermal grease layer is provided at the bottom of the heat pipe where it is connected to the copper nail array.

8. The heat dissipation enhanced current sensor housing according to claim 1, characterized in that, The alloy thin sheet is a nickel-titanium shape memory alloy thin sheet, and the thickness of the alloy thin sheet is 0.1 mm.

9. The heat dissipation enhanced current sensor housing according to claim 1, characterized in that, The Helmholtz resonance cavity includes a cuboid cavity and a neck channel connecting the cuboid cavity and the air outlet, and the gradually expanding opening is connected to the cuboid cavity.

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