Boiling heat transfer device cooperatively reinforced by grid electrode coupling distributed micropore-microcolumn composite surface

Abstract

The invention discloses a grid electrode coupled distributed micropore-microcolumn composite surface synergistically enhanced boiling heat transfer device, which comprises a base, a support frame, a negative electrode partition plate and a distributed micropore-microcolumn composite surface are fixedly arranged on the top surface of the base, the support frame and the distributed micropore-microcolumn composite surface penetrate through the negative electrode partition plate, and the support frame is provided with an insertion hole; the grid electrode comprises a base plate, the two sides of the base plate are fixedly connected with supporting strips, square holes are formed in the base plate, and the supporting strips are inserted into the inserting holes; the distributed micropore-microcolumn composite surface comprises a plurality of square micropore-microcolumn areas which are distributed in an array mode, a strip-shaped microcolumn area is arranged between every two adjacent micropore-microcolumn areas, micropores are formed in the tops of microcolumns of the micropore-microcolumn areas, and the micropore-microcolumn areas correspond to square holes formed in the base plate in a one-to-one mode and are the same as the square holes in size. Nucleation and separation of bubbles in the boiling process can be effectively promoted, thermal resistance is reduced, the wall surface superheat degree of the surface is greatly reduced, and the boiling heat transfer performance of the surface is remarkably enhanced.

Description

Technical Field

[0001] This invention belongs to the field of phase change heat transfer enhancement technology, specifically a boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed microporous-micropillar composite surface. Background Technology

[0002] Boiling heat transfer, as a common phase change heat transfer method, can remove a large amount of heat from the surface in a timely manner, reduce the surface wall temperature, and improve the surface heat transfer performance. It has become a heat dissipation technology with broad application prospects. In recent years, with the advent of the intelligent era, various devices and equipment have been developing towards high integration. The energy consumption of devices and equipment has increased significantly during operation, which has put forward higher requirements for the thermal management of devices and equipment. It is urgent to improve the heat dissipation efficiency of their heat dissipation systems, reduce the operating temperature of devices and equipment during operation, and maintain their safe, efficient, and stable operation. Therefore, strengthening the heat transfer performance of boiling heat transfer and improving the heat transfer coefficient of boiling heat transfer are of great significance for promoting the application of boiling heat dissipation technology.

[0003] In the study of enhancing boiling heat transfer, microstructured surfaces have become an important enhancement method because they can significantly increase the heat transfer area, improve the capillary wicking performance, and promote gas-liquid path separation. However, during boiling, microstructured surfaces cannot significantly increase the density of nucleated bubbles, and the enhancement of boiling heat transfer performance is limited, which cannot meet the current growing heat dissipation demand. Based on microstructured surfaces, hydrophobic modification or composite microporous structures can increase the number of nucleated bubbles on the surface. However, as the heat flux density increases, a large number of nucleated bubbles are prone to aggregate and merge into large bubbles, which will worsen the rewetting of the surface by the liquid, thereby increasing the thermal resistance and reducing the boiling heat transfer coefficient of the surface.

[0004] Currently, researchers are improving the boiling heat transfer performance of microstructures by applying external forces to regulate bubble behavior, based on increasing the nucleation density of microstructure surfaces. Among these methods, an external electric field is a simple and efficient enhancement method that can further enhance boiling heat transfer performance by reducing bubble diameter, promoting bubble detachment, hindering bubble aggregation, and increasing disturbance to the surface fluid. However, the "field trapping effect" when the external electric field acts on the microstructure surface and the obstruction effect of the electrode structure on bubble detachment will hinder the detachment of surface bubbles, weaken the enhancement effect of the external electric field on the microstructure surface, and are not conducive to improving the boiling heat transfer performance of the surface.

[0005] Therefore, while maintaining the surface nucleation density, it is necessary to optimize the electrode structure and increase the effective area of ​​the applied electric field by combining the dynamic behavior of nucleated bubbles, so as to establish a matching strategy between the applied electric field and the structural surface, avoid the "field trap effect" and the adverse effects of the electrode structure on bubble detachment, and improve boiling heat transfer performance. Summary of the Invention

[0006] The purpose of this invention is to provide a boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed microporous-micropillar composite surface. This device effectively promotes the nucleation and detachment of bubbles during boiling, reduces thermal resistance, significantly reduces surface wall superheat, and significantly enhances the boiling heat transfer performance of the surface.

[0007] This invention is achieved through the following technical solution:

[0008] A boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed microporous-micropillar composite surface includes a support frame, a grid electrode, a negative electrode partition, a base, and a distributed microporous-micropillar composite surface. The negative electrode partition is fixedly attached to the top surface of the base, and the negative electrode partition has a square hole for the distributed microporous-micropillar composite surface to pass through and two strip holes for a pair of support frames to pass through. The bottom of the distributed microporous-micropillar composite surface passes through the square hole in the negative electrode partition and is fixedly connected to the base. The bottom of the pair of support frames passes through the two strip holes in the negative electrode partition and is fixedly connected to the base. The pair of support frames have insertion holes with opposite positions.

[0009] The base has a positioning slot in the center of the top surface. The bottom of the distributed microporous-micropillar composite surface is embedded in the positioning slot and thus fixedly connected to the base. The distributed microporous-micropillar composite surface and the top surface of the negative electrode separator are on the same horizontal plane.

[0010] The grid electrode is a perforated plate structure, including a substrate and several square holes arranged in an array on the substrate. Support bars that match the insertion holes are symmetrically fixed on both sides of the substrate. The support bars are inserted into the insertion holes, thereby fixing the grid electrode above the base.

[0011] The distributed micropore-micropillar composite surface includes several square micropore-micropillar regions arranged in an array, with strip-shaped micropillar regions between two adjacent micropore-micropillar regions. The micropore-micropillar regions include array-distributed micropillars, and the top surface of the micropillars has array-distributed micropores. The micropillar regions include array-distributed micropillars.

[0012] The micropore-micropillar region corresponds one-to-one with the square holes opened on the substrate and has the same size.

[0013] Furthermore, four support columns are fixedly installed inside the positioning slot, and the bottom surface of the distributed micropore-micropillar composite surface is fixedly connected to the top surface of the four support columns.

[0014] Furthermore, the depth of the positioning slot is 2-3 mm.

[0015] Furthermore, the top surface of the base is provided with a pair of rectangular slots, and the bottom of the two support brackets are embedded in the rectangular slots to be fixedly connected to the base.

[0016] Furthermore, the base has a boss structure, with the upper section being a cylinder with a diameter of 70-100mm and the lower section being a cylinder with a diameter of 90-120mm, and the upper and lower sections are integrally formed.

[0017] Furthermore, both the support frame and the base are made of polytetrafluoroethylene.

[0018] Furthermore, the grid electrode is made of stainless steel, the thickness of the grid electrode is 0.3-0.5 mm, and several square holes distributed in an array are formed by laser drilling. The side length of the square holes is 500-900 μm, and the spacing between two adjacent square holes is 200-400 μm.

[0019] The distance between the grid electrode and the top surface of the base is 0.3 to 3.0 mm.

[0020] Furthermore, the distributed micropore-micropillar composite surface is formed by etching a single-crystal silicon wafer, and the side length of its square micropore-micropillar region is 500-900 μm, while the width of the strip-shaped micropillar region 8 is 200-400 μm.

[0021] Furthermore, the micropillar is a cuboid with a height of 30–100 μm, and its base is a square with a side length of 30–90 μm. The distance between two adjacent micropillars is 20–60 μm.

[0022] The number of micropores on the top surface of each micropillar in the micropore-micropillar region is 4 to 16.

[0023] Furthermore, the negative electrode separator is made of stainless steel, and the outer diameter of the negative electrode separator and the diameter of the upper section of the base are both 70-100mm.

[0024] The present invention has the following beneficial technical effects:

[0025] First, the distributed microporous-micropillar composite surface of the present invention is composed of a microporous-micropillar region and a micropillar region. On the one hand, the micropores on the top surface of the micropillars in the microporous-micropillar region can significantly increase the density of nucleation bubbles on the surface, promote nucleation boiling, and reduce the surface wall superheat. On the other hand, the micropillar region can prevent excessive coalescence and fusion of nucleation bubbles into large bubbles that completely cover the surface, reduce heat transfer resistance, promote bubble disturbance of the flow field, and enhance liquid rewetting of the surface, thereby improving the surface heat transfer performance. Second, by setting grid electrodes, the effective area of ​​the applied electric field can be increased, thereby improving the effectiveness of the electric field and making it easier to reduce the diameter of the bubbles, further hindering bubble coalescence. Furthermore, the matching arrangement of the square holes of the grid electrode with the square micropore-micropillar region of the distributed micropore-micropillar composite surface can provide a path for the detachment of nucleated bubbles on the distributed micropore-micropillar composite surface. In short, this invention fully utilizes the enhanced characteristics of the electric field to promote the detachment of bubbles at the top of the micropillars, increases the detachment frequency of bubbles, and combines the distributed micropore-micropillar composite surface to promote nucleation and hinder bubble aggregation. By coupling the grid electrode, it effectively promotes the nucleation and detachment of bubbles during boiling, reduces thermal resistance, and promotes the separation of gas-liquid paths during boiling, thereby significantly reducing the surface wall superheat, improving the surface boiling heat transfer coefficient, and significantly enhancing the surface boiling heat transfer performance of the boiling heat transfer device.

[0026] The grid electrode material of this invention is stainless steel plate, the distributed micropore-micropillar composite surface material is single crystal silicon wafer, and the polytetrafluoroethylene base and support frame are made of polytetrafluoroethylene. The materials are generally inexpensive, and the manufacturing process is mature and simple, using laser drilling, etching, and machining. In short, the boiling heat transfer device of this invention can be mass-produced, has good practicality, and can generate high economic benefits. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural schematic diagram of the boiling heat transfer device of the present invention;

[0028] Figure 2 This is a partial structural schematic diagram of the boiling heat transfer device of the present invention;

[0029] Figure 3 This is a schematic diagram of the polytetrafluoroethylene base of the present invention;

[0030] Figure 4 This is a schematic diagram of the grid electrode of the present invention;

[0031] Figure 5 This is a partial three-dimensional structural diagram of the distributed microporous-micropillar composite surface of the present invention;

[0032] Figure 6This is a partial top view of the distributed microporous-micropillar composite surface of the present invention;

[0033] Figure 7 This is a partial physical image of the distributed microporous-micropillar composite surface of Embodiment 1 of the present invention;

[0034] Figure 8 This describes the heat transfer performance of the boiling heat transfer device and the distributed microporous-micropillar composite surface of Example 1 of the present invention during subcooled boiling in HFE-7100 solution.

[0035] In the figure: 1. Support frame; 2. Grid electrode; 3. Negative electrode separator; 4. Positioning slot; 5. Base; 6. Distributed micropore-micropillar composite surface; 7. Micropore-micropillar region; 8. Micropillar region. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0037] refer to Figures 1-2 As shown, a boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed microporous-micropillar composite surface includes a support frame 1, a grid electrode 2, a negative electrode separator 3, a polytetrafluoroethylene base 5, and a distributed microporous-micropillar composite surface 6.

[0038] like Figure 3 As shown, the polytetrafluoroethylene base 5 is a cylindrical boss structure, with the upper section being a cylinder with a diameter of 70-100mm and the lower section being a cylinder with a diameter of 90-120mm. The base 5 has a positioning slot 4 and a pair of rectangular slots. Four support columns are fixedly installed in the positioning slot 4, and the positioning slot 4 is located in the central area of ​​the base 5. The pair of rectangular slots are located on both sides of the positioning slot 4. Two support frames 1 are fixedly installed inside the rectangular slots, and the two support frames 1 have opposite insertion holes. The bottom of the distributed micropore-micropillar composite surface 6 is fixedly connected to the top surface of the four support columns, thereby being embedded in the central area of ​​the base 5 through the positioning slot 4.

[0039] Preferably, the depth of the positioning slot 4 is 2-3 mm.

[0040] Preferably, both the support frame 1 and the base 5 are made of polytetrafluoroethylene.

[0041] like Figure 4 As shown, the main body of the grid electrode 2 is a perforated plate structure, including a substrate and several square holes arranged in an array on the substrate. The gap between two adjacent square holes is a strip frame. Support strips matching the insertion holes are symmetrically fixed on both sides of the substrate. The support strips are inserted into the insertion holes, thereby fixing the grid electrode 2 above the base 5.

[0042] Preferably, the thickness of the grid electrode 2 is 0.3 to 0.5 mm, the side length of the square hole on the grid electrode 2 is 500 to 900 μm, the width of the strip frame of the grid electrode 2 is 200 to 400 μm, and the distance between the grid electrode 2 and the top surface of the base 5 is 0.3 to 3.0 mm.

[0043] Preferably, the square electrode 2 is a stainless steel plate, and square holes are processed on the substrate by laser drilling.

[0044] like Figure 2 , Figures 4-7 As shown, the distributed micropore-micropillar composite surface 6 includes several square micropore-micropillar regions 7 arranged in an array, and a strip-shaped micropillar region 8 is formed between two adjacent micropore-micropillar regions 7. The micropore-micropillar region 7 includes micropillars arranged in an array, and the top surface of the micropillars is provided with micropores arranged in an array. The micropillar region 8 includes micropillars arranged in an array, and the top surface of the micropillars is not provided with micropores.

[0045] The square holes on the grid electrode 2 correspond one-to-one with the square micropore-micropillar regions 7 and have the same size. The strip frames on the grid electrode 2 correspond to the strip micropillar regions 8 and have the same size. That is, when the distributed micropore-micropillar composite surface 6 is embedded in the positioning slot 4, the micropore-micropillar regions 7 and micropillar regions 8 correspond vertically to the square holes and strip frames of the grid electrode 2, respectively.

[0046] Preferably, the distributed micropore-micropillar composite surface 6 is formed by etching a single crystal silicon wafer, the square micropore-micropillar region 7 has a side length of 500-900 μm, and the strip-shaped micropillar region 8 has a width of 200-400 μm.

[0047] Preferably, the micropillar is a cuboid with a square base having a side length of 30–90 μm and a height of 30–100 μm. The distance between two adjacent micropillars is 20–60 μm, and the number of micropores on the top surface of each micropillar is 4–16.

[0048] like Figure 1 As shown, the negative electrode separator 3 is fixedly installed on the upper surface of the base 5, and the negative electrode separator 3 has a square hole for the distributed microporous-micropillar composite surface 6 to pass through and a strip hole for the support frame 1 to pass through. The bottom of the distributed microporous-micropillar composite surface 6 passes through the square hole and is fixedly installed on the top surface of the four support columns. The top surface of the distributed microporous-micropillar composite surface 6 and the top surface of the negative electrode separator 3 are on the same horizontal plane. The bottom of a pair of support frames 1 passes through two strip holes and is fixedly installed on the top surface of the base 5.

[0049] Preferably, the negative electrode separator 3 is made of stainless steel, and the outer diameter of the negative electrode separator 3 is the same as the diameter of the upper section of the base 5, which is 70-100mm.

[0050] Preferably, the width of the square hole in the negative electrode separator 3 that allows the distributed microporous-micropillar composite surface 6 to pass through is the same as the size of the positioning slot 4, which allows the distributed microporous-micropillar composite surface 6 to pass through and allows the negative electrode separator 3 to cover the upper surface of the base 5 to the maximum extent.

[0051] Preferably, the upper surface of the base 5 is also provided with an annular groove, and the negative electrode separator 3 is correspondingly designed as an annular shape. The negative electrode separator 3 is embedded in the annular groove, so that the top surfaces of the negative electrode separator 3, the positioning slot 4 and the distributed micropore-micropillar composite surface 6 are on the same horizontal plane.

[0052] The processing method and structure of the boiling heat transfer device with grid electrode coupling distributed micropore-micropillar composite surface synergistic enhancement of the present invention will be explained in more detail through Examples 1 and 2.

[0053] Example 1

[0054] Step 1: Fabrication of a distributed microporous-micropillar composite surface

[0055] Take a 10mm×10mm×0.5mm single crystal silicon wafer and etch cuboid micropillars arranged in an array on it. The bottom surface of the micropillars is a square with a side length of 30μm, the height of the micropillars is 60μm, and the spacing between two adjacent micropillars is 30μm. Sixteen circular holes with a diameter of 3μm are opened in an array on the top surface of the 12×12-dimensional micropillars. The micropillars with circular holes are called micropore-micropillar composite structures. The 12×12-dimensional micropore-micropillar composite structure forms a square micropore-micropillar region 7 with a side length of 690μm. Between two adjacent micropore-micropillar regions 7 is a strip-shaped micropillar region 8 with a width of 360μm. The micropillar region 8 is composed of micropillars without micropores on the top surface.

[0056] Step 2: Fabrication of grid electrodes

[0057] Based on the dimensions of the distributed microporous-micropillar composite surface 6, a stainless steel plate with a thickness of 0.3 mm was taken, and three support strips were processed on both sides of the stainless steel plate. Then, square holes with a side length of 690 μm were processed on the stainless steel plate by laser drilling, and the gap width between two adjacent square holes was 360 μm.

[0058] Step 3: Make the base, positioning slots, and support frame.

[0059] The base 5 is processed using polytetrafluoroethylene. The upper part of the base 5 is a small cylinder with a diameter of 80mm and a height of 80mm, and the lower part is a large cylinder with a diameter of 110mm and a height of 30mm. The small cylinder and the large cylinder are integrally formed. A positioning groove 4 with a depth of 2mm and a pair of rectangular grooves are etched at the center of the top surface of the small cylinder.

[0060] The installation height of the grid electrode 2 is set to 2mm. Based on the size of the rectangular slot and the installation height of the grid electrode 2, two cuboid support frames 1 are processed, and insertion holes matching the support bars are opened at the relative positions of the two cuboid support frames 1.

[0061] Step 4: Fabricate the negative electrode separator

[0062] Take a stainless steel plate with a diameter of 80mm and a thickness of 0.3mm, and make a square hole with a side length of 12mm in the center. Make long strip holes with the same size as the rectangular slots on both sides of the square hole.

[0063] Step 5: Assemble the boiling heat transfer device

[0064] First, the negative electrode separator 3 is fixedly installed on the top surface of the small cylinder. Then, the bottom surface of the distributed micropore-micropillar composite surface 6 is embedded into the positioning slot 4. Next, the support strips on both sides of the grid electrode 2 are inserted into the insertion holes of the two support frames 1. Then, the support frame 1 is fixed in the rectangular slot. At this time, the micropore-micropillar region 7 and the micropillar region 8 correspond to the upper and lower positions of the square hole and the strip frame of the grid electrode 2, respectively.

[0065] The heat transfer performance of the assembled boiling heat transfer device was tested during subcooled boiling in HFE-7100 solution. During the test, the temperature of HFE-7100 solution was 26℃ and the subcooling was 35K. The grid electrode was connected to the positive terminal of the high-voltage power supply and a voltage of 2kV was applied. At the same time, in order to analyze the effect of the grid electrode on boiling heat transfer, the boiling heat transfer device with the grid electrode 2 and negative electrode partition 3 removed was used as a control group, and its heat transfer performance during subcooled boiling was tested under the same conditions.

[0066] Test results are as follows Figure 8 As shown, it can be seen that without the gridded electrodes, the surface heat flux density increases to 60 W / cm². 2 At that time, the superheat was 18K; with gridded electrodes, the surface heat flux density increased to 86 W / cm². 2 At that time, the superheat was only 4.7K; it can be seen that the boiling heat transfer coefficient of the boiling heat transfer device with grid electrode coupled distributed micropore-micropillar composite surface synergistic enhancement is greatly improved.

[0067] Example 2

[0068] Step 1: Fabrication of a distributed microporous-micropillar composite surface

[0069] Take a 10mm×10mm×0.5mm single crystal silicon wafer and etch rectangular micropillars arranged in an array on it. The bottom surface of the micropillars is a square with a side length of 70μm, the height of the micropillars is 100μm, and the spacing between two adjacent micropillars is 20μm. Four circular holes with a diameter of 3μm are opened on the top surface of the 10×10 dimensional micropillars in an array. The micropillars with circular holes are called micropore-micropillar composite structures. The 10×10 dimensional micropore-micropillar composite structure forms a square micropore-micropillar region 7 with a side length of 880μm. Between two adjacent micropore-micropillar regions 7 is a strip-shaped micropillar region 8 with a width of 250μm. The micropillar region 8 is composed of micropillars without micropores on the top surface.

[0070] Step 2: Fabrication of grid electrodes

[0071] Based on the dimensions of the distributed microporous-micropillar composite surface 6, a stainless steel plate with a thickness of 0.3 mm was taken, and three support strips were processed on both sides of the stainless steel plate. Then, square holes with a side length of 880 μm were processed on the stainless steel plate by laser drilling, and the gap width between two adjacent square holes was 250 μm.

[0072] Step 3: Make the base, positioning slots, and support frame.

[0073] The base 5 is made of polytetrafluoroethylene. The upper part of the base 5 is a small cylinder with a diameter of 70mm and a height of 90mm, and the lower part is a large cylinder with a diameter of 100mm and a height of 20mm. The small cylinder and the large cylinder are integrally formed. A positioning groove 4 with a depth of 2.5mm and a pair of rectangular grooves are etched at the center of the top surface of the small cylinder.

[0074] The installation height of the grid electrode 2 is set to 3mm. Based on the size of the rectangular slot and the installation height of the grid electrode 2, two cuboid support frames 1 are processed using polytetrafluoroethylene, and insertion holes matching the support bars are opened at the relative positions of the two cuboid support frames 1.

[0075] Step 4: Fabricate the negative electrode separator

[0076] Take a stainless steel plate with a diameter of 70mm and a thickness of 0.3mm, make a square hole with a side length of 12mm in the center, and make long strip holes with the same size as the rectangular slot on both sides of the square hole.

[0077] Step 5: Assemble the boiling heat transfer device

[0078] First, the negative electrode separator 3 is fixedly installed on the top surface of the small cylinder. Then, the bottom surface of the distributed micropore-micropillar composite surface 6 is embedded into the positioning slot 4. Next, the support strips on both sides of the grid electrode 2 are inserted into the insertion holes of the two support frames 1. Then, the support frame 1 is fixed in the rectangular slot. At this time, the micropore-micropillar region 7 and the micropillar region 8 correspond to the upper and lower positions of the square hole and the strip frame of the grid electrode 2, respectively.

Claims

1. A boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed microporous-micropillar composite surface, characterized in that, The device includes a support frame (1), a grid electrode (2), a negative electrode separator (3), a base (5), and a distributed microporous-micropillar composite surface (6). The negative electrode separator (3) is fixedly attached to the top surface of the base (5). The negative electrode separator (3) has a square hole through which the distributed microporous-micropillar composite surface (6) passes and two strip holes through which a pair of support frames (1) pass. The bottom of the distributed microporous-micropillar composite surface (6) passes through the square hole of the negative electrode separator (3) and is fixedly connected to the base (5). The bottom of the pair of support frames (1) passes through the two strip holes of the negative electrode separator (3) and is fixedly connected to the base (5). The pair of support frames (1) have insertion holes with opposite positions. The base (5) has a positioning slot (4) in the center of the top surface. The bottom of the distributed microporous-micropillar composite surface (6) is embedded in the positioning slot (4) and thus fixedly connected to the base (5). The top surfaces of the distributed microporous-micropillar composite surface (6) and the negative electrode separator (3) are on the same horizontal plane. The grid electrode (2) is a perforated plate structure, including a substrate and several square holes arranged in an array on the substrate. Support bars matching the insertion holes are symmetrically fixed on both sides of the substrate. The support bars are inserted into the insertion holes, thereby fixing the grid electrode (2) above the base (5). The distributed micropore-micropillar composite surface (6) includes several square micropore-micropillar regions (7) arranged in an array, and a strip-shaped micropillar region (8) is between two adjacent micropore-micropillar regions (7). The micropore-micropillar region (7) includes micropillars arranged in an array, and the top surface of the micropillars is provided with micropores arranged in an array. The micropillar region (8) includes micropillars arranged in an array. The micropore-micropillar region (7) corresponds one-to-one with the square holes opened on the substrate and has the same size.

2. The boiling heat transfer device with synergistic enhancement of distributed micropore-micropillar composite surface coupled with grid electrodes according to claim 1, characterized in that, Four support columns are fixedly installed inside the positioning slot (4), and the bottom surface of the distributed micropore-micropillar composite surface (6) is fixedly connected to the top surface of the four support columns.

3. The boiling heat transfer device with synergistic enhancement of distributed micropore-micropillar composite surface coupled with grid electrodes according to claim 2, characterized in that, The depth of the positioning slot (4) is 2-3 mm.

4. The boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed micropore-micropillar composite surface according to claim 1 or 2, characterized in that, The top surface of the base (5) is provided with a pair of rectangular slots, and the bottom of the two support brackets 1 are embedded in the rectangular slots so as to be fixedly connected to the base (5).

5. The boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed micropore-micropillar composite surface according to claim 1 or 2, characterized in that, The base (5) is a boss structure. The upper part of the base (5) is a cylinder with a diameter of 70-100mm, and the lower part of the base (5) is a cylinder with a diameter of 90-120mm. The upper and lower parts are integrally formed.

6. The boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed micropore-micropillar composite surface according to claim 1 or 2, characterized in that, Both the support frame (1) and the base (5) are made of polytetrafluoroethylene.

7. The boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed micropore-micropillar composite surface according to claim 1 or 2, characterized in that, The grid electrode (2) is made of stainless steel and has a thickness of 0.3 to 0.5 mm. Several square holes arranged in an array are formed by laser drilling. The side length of the square holes is 500 to 900 μm and the spacing between two adjacent square holes is 200 to 400 μm. The distance between the grid electrode (2) and the top surface of the base (5) is 0.3 to 3.0 mm.

8. The boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed micropore-micropillar composite surface according to claim 1 or 2, characterized in that, The distributed micropore-micropillar composite surface (6) is formed by etching a single crystal silicon wafer, and the side length of its square micropore-micropillar region (7) is 500-900 μm, and the width of its strip-shaped micropillar region (8) is 200-400 μm.

9. The boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed micropore-micropillar composite surface according to claim 1 or 2, characterized in that, The micropillars are cuboids with a height of 30–100 μm, and their bases are squares with a side length of 30–90 μm. The distance between two adjacent micropillars is 20–60 μm. The number of micropores on the top surface of each micropillar in the micropore-micropillar region (7) is 4 to 16.

10. The boiling heat transfer device with synergistic enhancement of a grid electrode coupled with a distributed micropore-micropillar composite surface according to claim 5, characterized in that, The negative electrode separator (3) is made of stainless steel, and the outer diameter of the negative electrode separator (3) and the diameter of the upper section of the base (5) are both 70-100 mm.

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