Periodic asymmetric Tesla microchannel two-phase cold plate and manufacturing method thereof

Abstract

The invention discloses a periodic asymmetric Tesla microchannel two-phase cold plate and a preparation method thereof. The cold plate comprises a cover plate, a substrate, asymmetric Tesla microchannels and a liquid separation cavity, the cover plate and the substrate are covered to form a sealing structure; working medium inlets and outlets are formed in two sides of the cover plate; a plurality of parallel asymmetric Tesla micro-channels at equal intervals are arranged in the middle of the substrate; the asymmetric Tesla microchannel is composed of Tesla units which are periodically and asymmetrically arranged on the upper side and the lower side, the Tesla unit on one side restrains steam countercurrent, and the Tesla unit on the other side promotes two-phase mixing of working media; the liquid separation cavities on two sides of the substrate are communicated with the micro-channel and are positioned below the inlet / outlet; the bottom of the substrate contacts with the power consumption device for heat exchange. The preparation method comprises the following steps: processing the cover plate, milling the asymmetric Tesla micro-channel and the liquid separation cavity on the substrate, cleaning and drying the micro-channel, and packaging the cover plate and the substrate. The device synchronously realizes steam countercurrent inhibition and two-phase mixing enhancement, improves the boiling heat exchange efficiency and the flow stability, and is suitable for two-phase heat dissipation of high-heat-flux electronic devices.

Description

Technical Field

[0001] This invention relates to the field of microchannel cold plate technology, and in particular to a periodic asymmetric Tesla microchannel two-phase cold plate and its preparation method. Background Technology

[0002] With the continuous iteration of microelectronics manufacturing and large-scale integrated circuit technology, the high miniaturization and high integration of power devices in fields such as aerospace, data centers, and electric transportation have led to a sharp increase in the heat flux density of these devices. For example, the local heat flux density of electronic components such as active phased array radar T / R modules and IGBT devices has reached 1000 W / cm², and in some extreme scenarios it even exceeds 3000 W / cm², far exceeding the limits of traditional single-phase heat dissipation technology. Traditional heat dissipation solutions such as forced air cooling, single-phase liquid cooling, and heat pipes are no longer sufficient to meet the high-efficiency heat dissipation requirements of high heat flux density devices in confined spaces. Therefore, high-efficiency two-phase cold plates have become a key bottleneck restricting the development of high-performance electronic devices.

[0003] In near-source heat dissipation scenarios, microchannel two-phase technology, with its high specific surface area and efficient utilization of the latent heat of liquid vaporization, has become a preferred solution for high heat flux density heat dissipation. However, due to the limitations of the channel size within the microchannel, the growth and merging of bubbles during boiling can easily lead to steam blockage and backflow, accompanied by drastic fluctuations in system pressure and flow rate. This results in obstructed liquid supply, large fluctuations in wall temperature, and ultimately induces localized drying, severely weakening heat dissipation stability and efficiency. Therefore, effectively suppressing microchannel steam backflow and two-phase instability is the primary problem that needs to be solved to achieve heat dissipation for high heat flux density electronic devices.

[0004] To address this issue, existing research mainly focuses on two aspects: firstly, introducing porous structures, nanowires, and other micro / nano structures into the channels to increase nucleation density and capillary transport capacity, thereby improving the evaporation efficiency of thin-film liquids; secondly, optimizing the channel structure design, such as by inlet restrictors, gradually expanding channels, or interconnected channels, to suppress vapor backflow and improve the uniformity of working fluid distribution. However, these approaches generally have drawbacks. Some approaches result in a significant increase in pressure drop during two-phase flow, increasing system energy consumption; others have limited effectiveness, only partially alleviating these problems, and still failing to achieve stable, directional two-phase flow throughout the entire channel under high heat flux density conditions.

[0005] The Tesla structure, with its unique asymmetric flow channel design, allows for smooth flow and low resistance in the forward direction, while significant momentum loss and flow resistance occur in the reverse direction due to the complex flow path, exhibiting a natural unidirectional conduction characteristic of "forward conduction and reverse flow obstruction." Introducing this structure into a microchannel flow boiling system effectively suppresses vapor backflow and induced flow instability without additional control components, providing a novel structural design approach for improving heat dissipation performance. However, existing Tesla microchannels mostly employ symmetrically arranged unit structures, whose enhancement effect is concentrated on suppressing vapor backflow, lacking the ability to regulate the mixing of the vapor and liquid phases in forward flow, and limiting local wall rewetting. Especially for electronic fluorinated liquids such as HFE-7100 and HFE-7000, poor rewetting ability and high vapor density easily lead to vapor congestion, thus the effect of suppressing vapor backflow is not significant. Ultimately, this limits the synergistic improvement of heat transfer coefficient and critical heat flux density in high heat flux density scenarios, making it difficult to meet the extreme heat dissipation requirements of next-generation electronic devices. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a periodic asymmetric Tesla microchannel two-phase cold plate and its manufacturing method. This cold plate simultaneously suppresses steam backflow and strong mixing of the vapor and liquid phases, effectively improving the problems of steam backflow and two-phase flow instability, enhancing heat transfer capacity throughout the boiling process, and ultimately ensuring stable and efficient heat dissipation of high-power devices by the microchannel cold plate.

[0007] Technical solution: The present invention provides a periodic asymmetric Tesla microchannel two-phase cold plate, comprising a cover plate, a substrate, an asymmetric Tesla microchannel, and a liquid separation chamber;

[0008] The cover plate fits onto the substrate and together they form a sealed structure; cooling medium inlet and cooling medium outlet are reserved on both sides of the cover plate, respectively;

[0009] The middle region of the substrate is provided with several parallel and equally spaced asymmetric Tesla microchannels, which are composed of periodically arranged and asymmetrically arranged Tesla units; liquid distribution chambers are provided on both the left and right sides of the substrate, which are connected to the asymmetric Tesla microchannels and are located directly below the cooling medium inlet and outlet; the bottom of the substrate is used to contact the power consumption device and realize heat exchange.

[0010] Optionally, a single asymmetric Tesla microchannel includes Tesla units arranged asymmetrically on the upper and lower sides and the bottom surface of the microchannel. The opening directions of the upper and lower Tesla units are opposite. The opening of one Tesla unit is away from the direction of the cooling medium flow, forming a structure that suppresses steam backflow; the opening of the other Tesla unit faces the direction of the cooling medium flow, forming a two-phase mixing structure.

[0011] Optionally, a single Tesla unit includes a curve, a straight channel, and a split island, with the included angle θ between the curve and the straight channel ranging from 0 to 180°.

[0012] Optionally, in the asymmetric Tesla microchannel, the Tesla unit curves arranged opposite each other on both sides have an intersection point with their adjacent Tesla unit curves, and the horizontal distance between these two intersection points can be set as needed.

[0013] Optionally, the angle between the Tesla cell channel and the horizontal axis is adjustable, ranging from 0 to 90°. With the total length remaining constant, this angle change can alter the number of Tesla cells in a single asymmetric Tesla microchannel.

[0014] Optionally, the shape of the flow divider island is selected from rectangular, trapezoidal or streamlined; one side of the flow divider island is parallel to the straight channel of the upper Tesla unit, and the other side of the flow divider island is parallel to the straight channel of the lower Tesla unit.

[0015] Optionally, the materials of the cover plate and the substrate are independently selected from any one or more combinations of the following, including copper, aluminum, stainless steel and their alloys, silicon and non-metallic alloys of elements in the same group, and other metallic materials, non-metallic materials or metal-based composite materials with good thermal conductivity, structural strength and corrosion resistance.

[0016] Optionally, the cooling medium is a fluid, including deionized water, a 20% volume fraction of ethylene glycol aqueous solution, electronic fluorinated liquid, and other heat exchange mediums with flow characteristics.

[0017] In another embodiment of the present invention, a method for manufacturing a periodically asymmetric Tesla microchannel two-phase cold plate, for preparing the cold plate, includes the following steps:

[0018] (1) Select a copper or copper alloy sheet as the substrate, clean and dry it to obtain a pretreated substrate;

[0019] (2) Fix the pre-treated substrate on a micro-milling machine, process an asymmetric Tesla microchannel in the middle of the substrate, and form liquid separation chambers on both sides of the substrate to ensure that the structural dimensions meet the design requirements;

[0020] (3) The processed substrate is cleaned and dried to obtain the initial processed substrate;

[0021] (4) Select copper or copper alloy thin plates as cover plates and process the working fluid inlet and outlet;

[0022] (5) Align and bond the pre-processed substrate with the cover plate, and perform brazing encapsulation under vacuum and protective atmosphere conditions;

[0023] (6) After the packaging is completed, the cold plate is cleaned and dried to obtain an asymmetric Tesla microchannel two-phase cold plate.

[0024] Furthermore, step (2) specifically involves:

[0025] Fabrication of asymmetric Tesla microchannels: Several parallel and equally spaced asymmetric Tesla microchannels are fabricated in the middle region of the substrate. The spacing between adjacent microchannels is set, as are the width and depth of each channel. A single microchannel consists of... It consists of a periodically arranged Tesla units with asymmetrical openings on both sides;

[0026] Fabrication of the liquid distribution chambers: Rectangular liquid distribution chambers are fabricated simultaneously on both sides of the substrate along its length. The width of the liquid distribution chambers is consistent with the total width of the microchannels to ensure direct communication with the microchannels.

[0027] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention include:

[0028] (1) Simultaneously achieve the suppression of steam backflow and the mixing of vapor and liquid phases, significantly improving heat exchange performance; This invention uses the differentiated structural design of asymmetric Tesla units. On one side, the backflow suppression structure is used to change the reverse steam flow path and increase the steam backflow loss, thereby suppressing steam backflow and avoiding local drying of the heat exchange surface. On the other side, the two-phase mixing structure with the bend opening facing the working fluid flow actively induces the cooling working fluid to form local disturbances, breaking the vapor-liquid two-phase stratification flow and strengthening the heat exchange process. Compared with traditional symmetric Tesla microchannels, this invention effectively makes up for its deficiency in two-phase mixing, significantly improving the critical heat flux density and convective heat transfer coefficient, and meeting the heat dissipation requirements of higher heat flux density.

[0029] (2) The stability of boiling is significantly enhanced and the reliability of operation is higher. Thanks to the effective suppression of steam counterflow and the full mixing of the vapor and liquid phases, the present invention can significantly reduce the wall temperature fluctuation and pressure drop fluctuation under high heat flux density conditions, and avoid the boiling instability problem. At the same time, the flow channel polarity of the asymmetric Tesla microchannel is 1, and the boiling heat transfer performance under forward and reverse flow is consistent. There is no need to strictly distinguish the installation direction, adapt to different system layout requirements, and further improve the reliability of operation.

[0030] (3) The preparation process is mature and suitable for large-scale application. The present invention adopts conventional processing technology such as precision micro-milling, mechanical drilling and brazing packaging, which can stably ensure the structural accuracy and consistency of the asymmetric Tesla unit. The entire preparation process does not require special complex equipment, the process is stable and the cost is controllable, and the sealing performance after packaging is reliable, which is suitable for industrial mass production. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a microchannel two-phase cold plate.

[0032] Figure 2 This is a schematic diagram of an asymmetric Tesla microchannel structure.

[0033] Figure 3 A schematic diagram of an asymmetric Tesla microchannel Tesla cell;

[0034] Figure 4 This is a schematic diagram of the asymmetric Tesla microchannel heat transfer mechanism.

[0035] Figure 5 A schematic diagram of an asymmetric Tesla microchannel structure with staggered positions;

[0036] Figure 6 A schematic diagram of micromilling an asymmetric Tesla microchannel structure;

[0037] Figure 7 Schematic diagram of mechanical drilling of cover plate;

[0038] Reference numerals: 1. Cover plate; 2. Working fluid outlet; 3. Working fluid inlet; 4. Separating chamber; 5. Asymmetric Tesla microchannel; 6. Diverting island; 7. Substrate; 8. Power consumption device; 9. Bend; 10. Straight channel; 11. Upper Tesla cell opening; 12. Lower Tesla cell opening; 13. Intersection between Tesla cells; 14. Milling cutter; 15. Drill bit. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0040] like Figure 1 As shown, this invention proposes a periodic asymmetric Tesla microchannel two-phase cold plate, comprising a cover plate 1, a working fluid outlet 2, a working fluid inlet 3, a liquid distribution chamber 4, asymmetric Tesla microchannels 5, and a substrate 7. The cover plate 1 and substrate 7 are closed to form a sealed structure, within which the cooling working fluid flows. The left and right sides of the cover plate 1 are respectively provided with a working fluid inlet 3 and a working fluid outlet 2 to guide the cooling working fluid in and out of the cold plate. The middle region of the substrate 7 has several parallel asymmetric Tesla microchannels 5, each composed of periodically arranged Tesla units with asymmetrical upper and lower sides. Liquid distribution chambers 4 are provided on both the left and right sides of the substrate 7, connected to the asymmetric Tesla microchannels 5, and located directly below the working fluid inlet 3 and working fluid outlet 2. The bottom of the substrate is used to contact a power-consuming device 8 for heat exchange.

[0041] The cooling medium (such as deionized water, 20% ethylene glycol solution, etc.) enters the liquid distribution chamber 4 from the working medium inlet 3, achieving uniform distribution through multiple channels. Then, it flows through the asymmetric Tesla microchannel 5 and absorbs heat from the power device 8. When flowing through the periodically arranged asymmetric Tesla units, the counter-current structure increases the momentum loss of the reverse steam through bends and flow islands to weaken the counter-current, while the two-phase mixing structure induces local disturbances, promotes the mixing of the vapor and liquid phases, and enhances heat transfer. Finally, the vapor-liquid mixture carrying heat is collected in the other liquid distribution chamber 4 and flows out from the working medium outlet 2, completing the heat dissipation cycle.

[0042] The materials of the cover plate and the substrate are independently selected from any one or more combinations of the following, including but not limited to copper, aluminum, stainless steel and their alloys, silicon and its group elements (such as germanium, tin, etc.) non-metallic alloys, and other metallic materials, non-metallic materials or metal-based composite materials with good thermal conductivity, structural strength and corrosion resistance.

[0043] The cooling medium is a fluid, including but not limited to deionized water, 20% ethylene glycol aqueous solution, electronic fluorinated liquid (e.g., HFE-7100, HFE-7000), and other heat exchange mediums with flow characteristics.

[0044] Figure 2 A schematic diagram of the asymmetric Tesla microchannel 5 is given. This microchannel consists of periodically arranged and asymmetrically positioned Tesla units on the upper and lower sides and the bottom surface of the microchannel, comprising a total of... One Tesla unit; among which , The length of a single Tesla unit. The total length of the asymmetric Tesla microchannel. The number of Tesla cells on one side of a single asymmetric Tesla microchannel. The diagram illustrates that the cooling medium flows from left to right, while the countercurrent steam flows from right to left. The microchannel structure differs from conventional Tesla microchannels; the asymmetrical arrangement on both sides means that the openings of the upper and lower Tesla units face opposite directions. One side opens towards the cooling medium inlet, and the other side opens towards the cooling medium outlet, forming a structure that suppresses steam backflow and a two-phase mixing structure, respectively. The flow polarity of this asymmetrical Tesla microchannel is 1, meaning that the flow characteristics remain consistent regardless of the direction in which the cooling medium flows in.

[0045] Figure 3A diagram of an asymmetric Tesla cell structure is provided. A single Tesla cell consists of a bend (9), a straight channel (10), and a flow divider (6). The angle between the bend and the straight channel of the Tesla cell is between 0 and 180°, and the flow directions of the upper and lower cells are asymmetrically designed. The opening (11) of the upper Tesla cell faces away from the direction of the cooling medium flow, forming a structure that suppresses steam backflow. The bend and the flow divider (6) change the flow path of the reverse steam and increase its momentum loss, thereby suppressing backflow. Specifically, when steam flows back from the channel outlet to the inlet, it passes through the Tesla cell on this side. Through the diversion effect of the flow divider, some steam enters the bend and its flow direction changes, colliding with the reverse steam and generating a large momentum loss. The opening (12) of the lower Tesla cell faces the direction of the cooling medium flow, forming a two-phase mixing structure. The mixing of the vapor and liquid phases is enhanced by inducing the flow of the working medium and the steam to impact each other. Specifically, when the cooling medium flows from the inlet to the outlet, the bend and the flow divider induce the working medium to mix. The openings of the two Tesla cells face different directions, forming an asymmetric Tesla structure.

[0046] The angle between the Tesla cell channel and the horizontal axis is adjustable, ranging from 0 to 90°. With the total length remaining constant, this angle change can alter the number of Tesla cells in a single asymmetric Tesla microchannel.

[0047] The shape of the flow island is selected from rectangular, trapezoidal or streamlined shapes to adapt to the microchannel structure to optimize the working fluid distribution effect and reduce flow resistance; different structural sizes and shapes can change the flow path and mixing effect of the cooling working fluid in the microchannel; one side of the flow island is parallel to the straight channel of the upper Tesla unit, and the other side of the flow island is parallel to the straight channel of the lower Tesla unit.

[0048] In summary, the Tesla cells on one side of the asymmetric Tesla microchannel are designed to suppress steam backflow. This is achieved by using flow dividers to alter the direction of the counter-current steam flow and increase its momentum loss, thus enhancing the stability of the two-phase flow during boiling heat transfer. The Tesla cells on the other side are designed for two-phase mixing. This is achieved by using flow dividers to induce mutual impact between the cooling medium and steam, thereby enhancing two-phase mixing, increasing interphase disturbance and rewetting, suppressing stratification and unstable flow, and maintaining the evaporation of the thin liquid film on the wall. The synergistic effect of these two structures improves both the heat transfer coefficient and the critical heat flux.

[0049] Figure 4A schematic diagram of the heat transfer mechanism of the cooling medium in an asymmetric Tesla microchannel substrate 7 is presented. The cooling medium flows from the left inlet to the right outlet. Due to the significant resistance to the incoming flow from the Tesla unit with its upper bend opening facing away from the direction of the working medium flow, and the presence of the flow divider island, the cooling medium mainly flows through the Tesla unit channel with its lower bend opening facing the direction of the incoming flow and the channels between the Tesla units arranged opposite to each other on both sides. When the working medium temperature reaches the saturation temperature at the corresponding pressure, it begins to boil. During the flow boiling process, the working medium generates steam in the channel; especially at the outlet, local drying causes a sudden increase in steam pressure, and the resulting reverse pressure gradient forces the steam to flow back towards the inlet. At this time, some of the countercurrent steam enters the Tesla unit with its bend opening facing away from the direction of the cooling medium flow. The steam collides at high speed with the bend wall along the straight channel of the Tesla unit on this side and changes its flow direction, thus significantly suppressing the steam counterflow. On the other hand, the incoming liquid enters the Tesla unit with its bend opening facing the direction of the cooling medium flow, impacting the steam in the main channel. The two undergo vigorous mixing and momentum exchange, a process that enhances the two-phase heat exchange efficiency.

[0050] Figure 5 An asymmetric Tesla microchannel structure is demonstrated by adjusting the horizontal spacing between two opposing Tesla cells on either side. In each cell, the curved channel intersects the straight channel of the adjacent cell at intersection point 13. The horizontal distance between the two opposing Tesla cells located on either side of the channel at their corresponding intersection points 13 is d. By changing the relative positions of the Tesla cells on both sides to adjust the spacing d, the flow state of the cooling medium can be optimized, thereby improving heat transfer uniformity.

[0051] With the increase in heat flux density (suitable for scenarios above 500W / cm²), the synergistic effect of the dual structure of the asymmetric Tesla microchannel becomes more significant: the counterflow suppression structure continuously avoids the risk of drying out, the two-phase mixing structure ensures heat exchange uniformity, and combined with the working fluid replenishment function of the liquid distribution chamber, the cold plate always maintains stable and efficient heat transfer performance.

[0052] The cold plate described in this invention optimizes the flow channel structure and uses asymmetrically arranged Tesla units to simultaneously suppress steam backflow and strong mixing of the vapor and liquid phases, effectively improving the problems of steam backflow and two-phase flow instability. It enhances heat transfer capability throughout the boiling process and ultimately ensures stable and efficient heat dissipation for high-power devices by the microchannel cold plate.

[0053] Figure 6 and Figure 7 A schematic diagram of the fabrication of an asymmetric Tesla microchannel and a cover plate is provided. This invention provides a method for preparing a copper-based asymmetric Tesla microchannel two-phase cold plate, specifically including the following steps:

[0054] (1) Substrate pretreatment: Select a copper or copper alloy thin plate as the substrate, clean and dry it to obtain a pretreated substrate; In this embodiment, a copper thin plate with a length of 40mm, a width of 15mm and a thickness of 3mm is selected as the substrate material. Use deionized water to clean the oil and impurities on the surface of the substrate, and then place it in a 60℃ constant temperature drying oven to dry for 20min to ensure that the surface is clean and dry to obtain a pretreated substrate;

[0055] (2) Microchannel and liquid distribution chamber processing: The pre-treated substrate is fixed on a micro-milling machine, an asymmetric Tesla microchannel is processed in the middle of the substrate, and liquid distribution chambers are formed on both sides of the substrate to ensure that the structural dimensions meet the design requirements; In this embodiment, the pre-treated substrate is fixed on the fixture of a precision micro-milling machine tool, and a carbide micro-milling cutter 14 with a diameter of 0.1-0.2mm is used to process the substrate at a milling speed of 15000r / min and a feed rate of 10mm / min.

[0056] Fabrication of asymmetric Tesla microchannels: Eight parallel and equally spaced asymmetric Tesla microchannels 5 are fabricated in the central region of the substrate. The spacing between adjacent microchannels is 0.6 mm, and each channel is 0.45 mm wide and 0.6 mm deep. Each microchannel consists of 24 periodically arranged Tesla units with asymmetrical openings on both sides. The unit length is 2.5 mm, and the total length of the microchannel is 30 mm. The angle between the curved and straight channels within the unit is 60°.

[0057] Fabrication of the liquid distribution chambers: Rectangular liquid distribution chambers 4 are simultaneously fabricated on both sides of the substrate along its length. The length of the liquid distribution chamber is 4mm, the width is consistent with the total width of the 8 microchannels, and the depth is 0.6mm to ensure direct communication with the microchannels.

[0058] The entire processing is controlled with an accuracy of ±0.02mm to ensure that the structural dimensions meet the design requirements.

[0059] (3) Substrate cleaning and drying: The processed substrate is cleaned and dried to obtain a pre-processed substrate; In this embodiment, the processed substrate is placed in an acetone solution ultrasonic cleaner for 15-25 minutes to remove surface organic matter; then it is transferred to a deionized water ultrasonic cleaner for 10-15 minutes to remove residual acetone; finally, it is placed in a 70℃ constant temperature drying oven for 30 minutes to obtain a pre-processed substrate.

[0060] (4) Cover plate processing: Select copper or copper alloy thin plate as cover plate, and process the cooling medium inlet and outlet; in this embodiment, a copper thin plate with a length of 40mm, a width of 15mm and a thickness of 3mm is selected as the base material of the upper cover plate 1. First, rinse the surface oil and impurities with deionized water, and then place it in a 70℃ constant temperature drying oven for 15min to remove surface moisture; refer to Figure 7The pre-treated upper cover plate 1 is fixed on the worktable of the mechanical drilling machine. A 2mm diameter carbide drill bit 15 is selected to symmetrically machine the working fluid inlet 3 and the working fluid outlet 2 on both sides of the length direction of the cover plate. The center distance between the two holes is 32mm, and the hole positions are centered along the width direction of the cover plate. After drilling, the hole wall is polished with fine sandpaper until the surface roughness Ra≤1.6μm to remove burrs and machining marks and reduce local resistance during the flow of working fluid.

[0061] (5) Encapsulation and soldering: Align and bond the pre-processed substrate with the cover plate, and perform brazing and encapsulation under vacuum and protective atmosphere conditions; In this embodiment, align the microchannel surface of the pre-processed substrate with the bonding surface of the cover plate, and place it in the brazing equipment; First, evacuate the equipment chamber to 5×10⁻ 4 Pa, then argon gas is introduced as a protective gas; the brazing temperature is set to 550℃, and the encapsulation is completed after holding the temperature for 20 minutes to ensure that the cover plate and the substrate are tightly bonded.

[0062] (6) Final cleaning and finished product: After packaging, the cold plate is cleaned and dried to obtain the asymmetric Tesla microchannel two-phase cold plate; in this embodiment, the cold plate to be packaged is naturally cooled to room temperature in the equipment and then taken out. Deionized water is used to clean any residual flux and other contaminants on its surface, and then it is dried to obtain the finished asymmetric Tesla microchannel two-phase cold plate.

[0063] The core of this invention addresses the technical pain point of existing microchannel cold plates, which cannot simultaneously achieve the suppression of vapor backflow and the enhancement of vapor-liquid two-phase mixing, providing an efficient solution for heat dissipation of high heat flux density electronic devices. The core innovation of this invention lies in the design of periodically arranged asymmetric Tesla cells. One side of the Tesla cell opening faces away from the working fluid flow to suppress vapor backflow, while the other side opening faces the working fluid flow to enhance two-phase mixing. This simultaneously achieves the suppression of vapor backflow and the enhancement of vapor-liquid mixing, improving the problems of dryness and uneven heat exchange in traditional microchannels. The accompanying liquid distribution chamber ensures uniform distribution of the working fluid. The materials of the top cover and substrate are flexibly adaptable. The cooling working fluid is compatible with deionized water, 20% volume fraction ethylene glycol aqueous solution, and electronic fluorinated liquids such as HFE-7100 and HFE-7000, adapting to the heat dissipation scenarios of high-power electronic components.

Claims

1. A periodically asymmetric Tesla microchannel two-phase cold plate, characterized in that: Includes cover plate, substrate, asymmetric Tesla microchannel and dispensing chamber; The cover plate fits onto the substrate and together they form a sealed structure; cooling medium inlet and cooling medium outlet are reserved on both sides of the cover plate, respectively; The middle region of the substrate is provided with several parallel and equally spaced asymmetric Tesla microchannels, which are composed of periodically arranged and asymmetrically arranged Tesla units; liquid distribution chambers are provided on both the left and right sides of the substrate, which are connected to the asymmetric Tesla microchannels and are located directly below the cooling medium inlet and outlet; the bottom of the substrate is used to contact the power consumption device and realize heat exchange.

2. The cold-rolled plate according to claim 1, characterized in that: Each asymmetric Tesla microchannel includes Tesla units arranged asymmetrically on the upper and lower sides and the bottom surface of the microchannel. The opening directions of the upper and lower Tesla units are opposite. The opening of one Tesla unit is away from the direction of the cooling medium flow, forming a structure that suppresses steam backflow; the opening of the other Tesla unit is towards the direction of the cooling medium flow, forming a two-phase mixing structure.

3. The cold-rolled plate according to claim 2, characterized in that: A single Tesla unit includes curves, straight sections, and split islands, with the angle θ between curves and straight sections ranging from 0 to 180°.

4. The cold plate according to claim 3, characterized in that: In the asymmetric Tesla microchannel, the Tesla unit curves arranged opposite each other on both sides have an intersection point with their adjacent Tesla unit curves, and the horizontal distance between these two intersection points is set as needed.

5. The cold-rolled plate according to claim 3, characterized in that: The angle between the Tesla cell channel and the horizontal axis is adjustable, ranging from 0 to 90°. With the total length remaining constant, this angle change can alter the number of Tesla cells in a single asymmetric Tesla microchannel.

6. The cold plate according to claim 3, characterized in that: The shape of the flow divider island is selected from rectangular, trapezoidal or streamlined; one side of the flow divider island is parallel to the straight channel of the upper Tesla unit, and the other side of the flow divider island is parallel to the straight channel of the lower Tesla unit.

7. The cold-rolled plate according to claim 1, characterized in that: The materials of the cover plate and the substrate are independently selected from any one or more combinations of the following, including copper, aluminum, stainless steel and their alloys, silicon and non-metallic alloys of elements in the same group, and other metallic materials, non-metallic materials or metal-based composite materials with good thermal conductivity, structural strength and corrosion resistance.

8. The cold-rolled plate according to claim 1, characterized in that: The cooling medium is a fluid medium, including deionized water, 20% ethylene glycol aqueous solution by volume, electronic fluorinated liquid, and other heat exchange mediums with flow characteristics.

9. A method for manufacturing a periodically asymmetric Tesla microchannel two-phase cold plate, characterized in that: The method for preparing the cold plate according to any one of claims 1-8 includes the following steps: (1) Select a copper or copper alloy sheet as the substrate, clean and dry it to obtain a pretreated substrate; (2) Fix the pre-treated substrate on a micro-milling machine, process an asymmetric Tesla microchannel in the middle of the substrate, and form a liquid distribution chamber on both sides of the substrate to ensure that the structural dimensions meet the design requirements; (3) The processed substrate is cleaned and dried to obtain the initial processed substrate; (4) Select copper or copper alloy thin plates as cover plates and process the working fluid inlet and outlet; (5) Align and bond the pre-processed substrate with the cover plate, and perform brazing encapsulation under vacuum and protective atmosphere conditions; (6) After the packaging is completed, the cold plate is cleaned and dried to obtain an asymmetric Tesla microchannel two-phase cold plate.

10. The method according to claim 9, characterized in that: Step (2) specifically involves: Fabrication of asymmetric Tesla microchannels: Several parallel and equally spaced asymmetric Tesla microchannels are fabricated in the middle region of the substrate. The spacing between adjacent microchannels is set, as are the width and depth of each channel. A single microchannel consists of... It consists of a periodically arranged Tesla units with asymmetrical openings on both sides; Fabrication of the liquid distribution chambers: Rectangular liquid distribution chambers are fabricated simultaneously on both sides of the substrate along its length. The width of the liquid distribution chambers is consistent with the total width of the microchannels to ensure direct communication with the microchannels.

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