Micro-channel heat sink with composite biomimetic structure
By setting up an array of staggered biomimetic ribs and periodic triangular cavities in the microchannel, the problem of insufficient flow boiling vaporization nuclei in the microchannel heat exchanger is solved, thereby improving heat exchange efficiency and reducing boiling instability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2023-01-03
- Publication Date
- 2026-05-29
AI Technical Summary
Existing microchannel heat exchangers lack sufficient fluid boiling vaporization nuclei, resulting in localized hot spots under high heat flux. The critical heat flux density within the microchannels is low, leading to low heat exchange efficiency.
By setting up an array of staggered biomimetic ribs and periodic triangular cavities in the microchannel, the boiling vaporization core is enhanced, ensuring timely wetting and cooling of the dry area and increasing the critical heat flux density.
By adding boiling vaporization nuclei, the heat exchange efficiency of the microchannel heat exchanger was improved, boiling instability was reduced, and temperature uniformity was improved.
Smart Images
Figure CN116772634B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of heat exchange technology, specifically relating to a microchannel radiator with a composite biomimetic structure. Background Technology
[0002] With the rapid development of science and technology, the integration level of equipment in fields such as microelectronics, medical devices, biochemicals, laser equipment, and aerospace is increasing, and the heat load of their heat exchange systems is also increasing. Therefore, microscale thermal management systems are indispensable, prompting the development of efficient and compact heat exchangers. Microchannel heat exchangers are highly efficient, compact in structure, have low coolant flow rates, and uniform wall temperature distribution, showing broad application prospects.
[0003] With the research on microchannel heat exchangers, the latent heat of vaporization of the working fluid can effectively improve the two-phase heat transfer coefficient, reduce the surface temperature, and improve the temperature uniformity, thereby ensuring the normal operation of the equipment. However, the existing phase change heat transfer microchannels are affected by the vaporization nucleation effect and local drying in the channel, and the boiling is unstable. The critical heat flux density also needs to be improved. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a microchannel radiator with a composite biomimetic structure, which solves the technical problems of insufficient flow boiling vaporization cores, local hot spots under high heat flux, and low critical heat flux density in existing microchannel heat exchanger devices, resulting in low heat exchange efficiency.
[0005] To achieve the above-mentioned technical objectives, the present invention is implemented through the following technical solution:
[0006] A microchannel heat sink with a composite biomimetic structure includes: bolts, a glass top cover, a sealing gasket, a silicon-based composite biomimetic microchannel heat sink, an intermediate heat insulation block, a copper-based heating block, a base heat insulation block, and nuts;
[0007] A copper-based heating block is embedded in the middle of the base heat insulation block, and an intermediate heat insulation block is installed above the base heat insulation block, with the upper end of the copper-based heating block embedded in the intermediate heat insulation block; a silicon-based composite biomimetic microchannel heat sink is installed in the middle of the upper surface of the intermediate heat insulation block, and a sealing gasket is installed in the gasket groove on the upper surface of the intermediate heat insulation block; a glass cover plate is installed on the entire upper surface of the intermediate heat insulation block; bolts pass through the glass cover plate and exit from the lower end of the base heat insulation block, and are used with nuts to fix the base heat insulation block, intermediate heat insulation block, and glass cover plate together.
[0008] Preferably, the upper surface of the silicon-based composite biomimetic microchannel heat sink is provided with a composite biomimetic microchannel, and four first temperature measurement holes are arranged on the side of the test piece. The composite biomimetic microchannel has a width of 0.26 mm, a height of 0.10 mm, and a length of 10.00 mm. An array of shark scute biomimetic ribs arranged in an alternating manner is provided on the bottom wall of the channel along the liquid flow direction, and periodically arranged triangular recesses are provided on the side walls.
[0009] Each shark dermal rib array includes a first biomimetic rib, a second biomimetic rib, and a third biomimetic rib. The first biomimetic rib, the second biomimetic rib, and the third biomimetic rib are arranged parallel to each other and at equal intervals on the bottom wall of the biomimetic rib microchannel to form a biomimetic rib array.
[0010] The first, second, and third biomimetic ribs have the same width and height, denoted as 'a' and 'h' respectively; the length of the second biomimetic rib is denoted as 'b', and the lengths of the first and third biomimetic ribs are equal, denoted as 'c'; 'a' is 0.02–0.03 mm, 'b' is 0.18–0.2 mm, and 'c' is 0.08–0.1 mm; the height 'h' is not greater than 1 / 10 of the height of the flow channel in the constant cross-section region of the liquid flow.
[0011] The triangular recess is an isosceles triangle with a base length equal to the length b of the second biomimetic rib, which is 0.18–0.2 mm, and a height of 0.04 mm.
[0012] Preferably, the intermediate heat-insulating block is further provided with two fluid pressure-stabilizing tanks, which are respectively arranged on both sides of the test piece mounting groove, and are respectively the first fluid pressure-stabilizing tank and the second fluid pressure-stabilizing tank; a first through-body for placing a silicon-based composite biomimetic microchannel heat sink is arranged between the first fluid pressure-stabilizing tank and the second fluid pressure-stabilizing tank; from left to right, the heat exchange medium inlet, the first fluid pressure-stabilizing tank, the composite biomimetic microchannel heat sink, the second fluid pressure-stabilizing tank, and the heat exchange medium outlet are connected in sequence;
[0013] Preferably, the side of the intermediate heat insulation block is provided with 8 temperature measuring holes, which are used to monitor the temperature; wherein the 4 temperature measuring holes on the upper side are connected to the 4 temperature measuring holes on the silicon-based composite biomimetic microchannel heat sink, and the 4 temperature measuring holes on the lower side are connected to the 4 temperature measuring holes on the copper-based heating block.
[0014] Preferably, the heat exchange medium inlet and the heat exchange medium outlet are respectively provided with a first pressure measuring port and a second pressure measuring port that can be connected to a pressure sensor. The first pressure measuring port and the second pressure measuring port are used to measure the pressure inside the heat exchange medium inlet and the heat exchange medium outlet.
[0015] Preferably, the stepped groove on the upper side of the copper-based heating block contacts the bottom of the silicon-based composite biomimetic microchannel heat sink. The copper-based heating block has heating holes inside for installing single-head electric heating tubes. The copper-based heating block is stepped, and the lower surface area of the stepped groove is the same as the bottom area of the composite biomimetic microchannel heat sink. A total of 2×2 single 10W electric heating tubes are arranged in the heating holes.
[0016] The beneficial effects of this invention are:
[0017] The microchannel phase change heat transfer experimental device and microchannel heat exchanger with composite biomimetic structure described in this invention increase the boiling vaporization core by setting staggered arrays of biomimetic ribs and periodic triangular recesses in the microchannel, ensuring that the dry area in the heat exchange microchannel is wetted and cooled by the working medium in time, thereby increasing the critical heat flux density and effectively improving the heat exchange efficiency of the microchannel heat exchanger. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the overall assembly structure of the composite biomimetic microchannel heat sink in this invention.
[0019] Figure 2 This is a three-dimensional structural schematic diagram of the composite biomimetic microchannel heat sink in this invention;
[0020] Figure 3 This is a schematic diagram of the composite biomimetic microchannel heat sink structure from the top view in this invention;
[0021] Figure 4 This is a three-dimensional structural diagram of the intermediate heat-insulating block in this invention;
[0022] Figure 5 This is a cross-sectional schematic diagram of the copper-based heating block in this invention;
[0023] Figure 6 This is a schematic diagram of the second through-body position structure in the base heat insulation block;
[0024] Figure 7 This is a microchannel flow boiling numerical simulation gas phase distribution cloud map from Example 2 of this invention;
[0025] Figure 8 This is the boiling curve of the microchannel flow boiling numerical simulation in Example 2 of this invention;
[0026] In the attached diagram, the structural names represented by each number are as follows:
[0027] 1- Bolt, 2- Glass top cover, 3- Sealing gasket, 4- Silicon-based composite biomimetic microchannel heat sink, 41- Temperature measurement hole, 42- Composite biomimetic microchannel, 421- Shark shield scale biomimetic rib array; 422- Triangular recess, 5- Intermediate heat insulation block, 511- Heat exchange medium inlet, 512- Heat exchange medium outlet, 521- First pressure measuring port, 522- Second pressure measuring port, 531- First fluid pressure stabilizing tank, 532- Second fluid pressure stabilizing tank, 54- First central through-body, 55- Outer temperature measurement hole, 56- Sealing gasket groove, 57- Screw hole, 6- Copper-based heating block, 61- Stepped groove, 62- Thermocouple temperature measurement hole, 63- Heating hole, 7- Base heat insulation block, 71- Second central through-body, 8- Nut. Detailed Implementation
[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0029] Example 1
[0030] like Figure 1 As shown, a biomimetic composite biomimetic microchannel heat sink includes a glass top cover plate 2 stacked from top to bottom and fixed by bolts 1 and nuts 8, a silicon-based composite biomimetic microchannel heat sink 4, a sealing gasket 3, an intermediate heat insulation block 5 containing inlet and outlet, a copper-based heating block 6, and a base heat insulation block 7.
[0031] like Figure 1 As shown, in this example, the bolt 1 has a bolt height of 65mm, the outermost four bolt connection holes have a diameter of 6mm, and the remaining bolt connection holes have a diameter of 3mm; the glass cover plate 2 has dimensions of 120mm × 40mm × 5mm; the silicon-based composite biomimetic microchannel heat sink 4 is an integral rectangular structure, with four circular temperature measurement holes 41 arranged on the side of the heat sink. The dimensions of the silicon-based composite biomimetic microchannel heat sink 4 are 15mm × 5mm × 2mm, the diameter of the temperature measurement holes 41 on the side of the heat sink is 0.5mm, the depth is 2.5mm, and the height is 1mm below the bottom surface of the silicon-based composite biomimetic microchannel heat sink 4. The two upper temperature measurement holes 41 at the edge are both 2.5mm away from the edge of the heat sink at a horizontal distance; the two upper temperature measurement holes 41 in the middle are both 5.0mm away from the edge of the heat sink at a horizontal distance.
[0032] The thickness of the sealing gasket 3 is 1mm. The outer rectangular dimensions of the sealing gasket 3 are 74mm×15mm, the inner rectangular dimensions are 70mm×11mm, and the chamfer radius on all four sides is 3mm.
[0033] like Figure 4 As shown, a pipe-shaped heat exchange medium inlet 511 and a heat exchange medium outlet 512 are respectively arranged on the left and right sides of the intermediate heat insulation block 5, which includes inlet and outlet. The heat exchange medium inlet 511 and the heat exchange medium outlet 512 are respectively connected to the first fluid pressure stabilizing tank 531 and the second fluid pressure stabilizing tank 532. A first central body 54 for placing the silicon-based composite biomimetic microchannel heat sink 4 is arranged between the first fluid pressure stabilizing tank 531 and the second fluid pressure stabilizing tank 532.
[0034] Eight circular thermocouples are arranged on the side of the intermediate heat-insulating block 5, which includes inlet and outlet, in the outer temperature measurement holes 55. The four outer temperature measurement holes 55 in the upper row are connected to the temperature measurement holes 41 of the silicon-based composite biomimetic microchannel heat sink 4.
[0035] The total height of the heat insulation block 5 is 10mm; the height of the first fluid pressure stabilizing tank 531 and the second fluid pressure stabilizing tank 532 is 6mm, and the length is 20mm. The width of the side where the first fluid pressure stabilizing tank 531 connects to the heat exchange medium inlet 511 and the second fluid pressure stabilizing tank 532 connects to the heat exchange medium outlet 512 is 3mm. The width of the inlet of the first fluid pressure stabilizing tank 531 connecting to the silicon-based composite biomimetic microchannel heat sink 4 is 3mm. The width of the outlet of the silicon-based composite biomimetic microchannel heat sink 4 connecting to the second fluid pressure stabilizing tank 532 is 3mm. The inner diameter of the heat exchange medium inlet 511 and the heat exchange medium outlet 512 is 4mm, the outer diameter is 10mm, and the length is 30mm.
[0036] like Figure 5 As shown, the copper-based heating block 6 has a stepped groove 61 at the center of its top for placing a silicon-based composite biomimetic microchannel heat sink 4. Two vertically arranged circular thermocouple temperature measuring holes 62 are arranged on its side. These thermocouple temperature measuring holes 62 are connected to two outer temperature measuring holes 55 on the upper and lower sides of the central heat-insulating block 5. The heating hole 63 for placing a single-ended electric heating tube is cylindrical. The upper small cuboid of the copper-based heating block 6 has dimensions of 15mm × 5mm × 8mm, and the lower large cuboid has dimensions of 20mm × 8mm. m×44mm; the height of the transition trapezoid between the small and large cuboids is 2mm; the depth of the stepped groove 61 on the upper surface of the copper-based heating block 6 is 0.5mm; the two outer temperature measuring holes 55 on the side of the copper-based heating block 6 are 2mm and 6mm away from the top of the copper-based heating block 6, respectively; the second temperature measuring hole is the outer temperature measuring hole corresponding to the inner side of the middle heat insulation block 5, with a diameter of 0.5mm and a depth of 4mm; the heating hole 63 of the single-head electric heating tube inside the copper-based heating block 6 has a diameter of 2mm and a height of 44mm;
[0037] like Figure 7As shown, the second central body 71 in the center of the base heat insulation block 7 is rectangular, and the length, width and height of the second central body 71 in the base heat insulation block 7 are 120mm×40mm×50mm.
[0038] In this example, the biomimetic composite biomimetic structure microchannel heat sink can be processed using micromachining processes such as microcutting / micromilling or additive manufacturing technology, while the other components can be processed using CNC machine tools.
[0039] Example 2
[0040] Due to the diversion effect, the flow rate entering each microchannel is the same. To simplify the simulation, this test performs numerical simulation on a single microchannel. The following describes the flow boiling performance of the biomimetic composite biomimetic structure microchannel.
[0041] The flow and temperature fields of a novel microchannel heat exchanger were numerically simulated using computational fluid dynamics (CFD) software to study its internal flow and temperature fields. Simulation conditions: The composite biomimetic microchannel heat sink was made of pure silicon, and the heat exchange medium was deionized water.
[0042] The inlet conditions for the heat exchange medium (511) are: flow rate 0.12974 g / s, inlet temperature 88℃. The outlet conditions for the heat exchange medium (512) are: pressure outlet. The total heating power of the electric heating tubes is 0-20W.
[0043] Simulation results:
[0044] Bionic silicon-based composite bionic microchannels and rectangular microchannels flow boiling gas phase distribution cloud diagrams are shown below. Figure 7 As shown, at low heat flux densities, the composite biomimetic microchannel has more boiling nucleation points than the rectangular microchannel; at high heat flux densities, the composite biomimetic microchannel has a smaller local drying area and lower boiling instability compared to the rectangular microchannel.
[0045] The main evaluation index for the heat transfer performance of fluids in microchannels is the hot wall superheat temperature ΔT. The lower the hot wall superheat temperature ΔT, the better the heat transfer effect of the flow channel.
[0046] Where the superheat of the hot wall surface ΔT=T w -T sat The simulation results of ΔT in this embodiment are as follows: Figure 8 As shown, the overall performance of the composite biomimetic microchannel is demonstrated by comparing it with that of a traditional rectangular microchannel with the same parameters. Figure 8 The average temperature ΔT of the hot wall surface is the result of different heat flux densities. Because the composite biomimetic microchannel structure can increase the vaporization core and ensure that the dry area in the heat exchange microchannel is promptly re-wetted, the heat exchange efficiency of the microchannel heat exchanger is effectively improved, and the hot wall surface temperature is lower than that of the traditional rectangular microchannel.
[0047] In summary, replacing traditional rectangular microchannels with composite biomimetic microchannels can significantly improve heat dissipation efficiency and reduce boiling instability.
Claims
1. A microchannel radiator with a composite biomimetic structure for heat transfer through fluid boiling within a microchannel, characterized in that, include: Bolts, glass cover plate, sealing gaskets, silicon-based composite biomimetic microchannel heat sink, intermediate heat insulation block, copper-based heating block, base heat insulation block, nuts; A copper-based heating block is embedded in the middle of the base heat insulation block, and an intermediate heat insulation block is installed above the base heat insulation block, with the upper end of the copper-based heating block embedded in the intermediate heat insulation block; a silicon-based composite biomimetic microchannel heat sink is installed in the middle of the upper surface of the intermediate heat insulation block, and a sealing gasket is installed in the gasket groove on the upper surface of the intermediate heat insulation block; a glass cover plate is installed on the entire upper surface of the intermediate heat insulation block; bolts pass through the glass cover plate and exit from the lower end of the base heat insulation block, and are used with nuts to fix the base heat insulation block, intermediate heat insulation block, and glass cover plate together. The upper surface of the silicon-based composite biomimetic microchannel heat sink is provided with a composite biomimetic microchannel. Four first temperature measurement holes are arranged on the side of the silicon-based composite biomimetic microchannel heat sink. The composite biomimetic microchannel has a width of 0.26 mm, a height of 0.10 mm, and a length of 10.00 mm. An array of staggered shark scute biomimetic ribs is arranged along the liquid flow direction on the bottom wall of the channel, and periodically arranged triangular recesses are provided on the side walls. Each shark scute biomimetic rib array includes a first biomimetic rib, a second biomimetic rib, and a third biomimetic rib. The first, second, and third biomimetic ribs are arranged parallel and equidistantly on the bottom wall of the biomimetic rib microchannel to form a biomimetic rib array. The first, second, and third bionic ribs have the same width and height, denoted as 'a' and 'h' respectively. The length of the second bionic rib is denoted as 'b', and the lengths of the first and third bionic ribs are equal, denoted as 'c'. 'a' is 0.02–0.03 mm, 'b' is 0.18–0.2 mm, and 'c' is 0.08–0.1 mm. The triangular recess is an isosceles triangle with a base length equal to the length 'b' of the second bionic rib, which is 0.18–0.2 mm, and a height of 0.04 mm.
2. The microchannel radiator with a composite biomimetic structure for fluid boiling and heat transfer within a microchannel, as described in claim 1, is characterized in that... The intermediate heat-insulating block is also provided with two fluid pressure-stabilizing tanks, which are respectively located on both sides of the silicon-based composite biomimetic microchannel heat sink mounting groove, and are respectively the first fluid pressure-stabilizing tank and the second fluid pressure-stabilizing tank; a first intermediate body for placing the silicon-based composite biomimetic microchannel heat sink is arranged between the first fluid pressure-stabilizing tank and the second fluid pressure-stabilizing tank; from left to right, the heat exchange medium inlet, the first fluid pressure-stabilizing tank, the composite biomimetic microchannel heat sink, the second fluid pressure-stabilizing tank, and the heat exchange medium outlet are connected in sequence.
3. The microchannel radiator with a composite biomimetic structure for fluid boiling and heat transfer within a microchannel, as described in claim 1, is characterized in that... The middle heat-insulating block has eight temperature measurement holes on its side for monitoring the temperature. The four temperature measurement holes on the upper side are connected to the four temperature measurement holes on the silicon-based composite biomimetic microchannel heat sink, and the four temperature measurement holes on the lower side are connected to the four temperature measurement holes on the copper-based heating block.
4. A microchannel radiator with a composite biomimetic structure for heat transfer through fluid boiling within a microchannel, as described in claim 2, is characterized in that... The heat exchange medium inlet and outlet are respectively provided with a first pressure measuring port and a second pressure measuring port that can be connected to a pressure sensor. The first pressure measuring port and the second pressure measuring port are used to measure the pressure inside the heat exchange medium inlet and the heat exchange medium outlet.
5. A microchannel radiator with a composite biomimetic structure for heat transfer through fluid boiling within a microchannel, as described in claim 1, is characterized in that... The stepped groove on the upper side of the copper-based heating block contacts the bottom of the silicon-based composite biomimetic microchannel heat sink. The copper-based heating block has heating holes inside for installing single-head electric heating tubes. The copper-based heating block is stepped, and the lower surface area of the stepped groove is the same as the bottom area of the composite biomimetic microchannel heat sink. A total of 2×2 single electric heating tubes with a power of 10W are arranged in the heating holes.