Micro-channel cooling device and regulation method

Abstract

The application discloses a kind of micro-channel cooling device and regulation and control method, micro-channel cooling device includes liquid supply unit, cooling unit and control unit, liquid supply unit is used to continuously provide cooling liquid to cooling unit;Cooling unit includes the parallel cold plate array of arrangement in the surface of electronic device;Control unit includes negative pressure regulating tank, vacuum pump and multistage pressure regulating and throttling component, for building stable negative pressure environment in system and regulating and controlling cooling liquid flow.In the process of operation, water working substance occurs low-temperature boiling phase change in micro-channel under negative pressure condition, absorbs high heat flux heat by latent heat of phase change, and the generated gas-liquid mixture realizes unidirectional stable transport under the action of rectifying structure, and completes gas-liquid separation in negative pressure regulating tank through hydrophobic air-permeable membrane, steam is extracted and dissipated to external environment.The application can significantly improve the heat dissipation capacity and operation stability under the condition of extremely high heat flux at low cost operation, and is suitable for high-power electronic device high-efficiency thermal management.

Description

Technical Field

[0001] This invention relates to the field of thermal management of electronic devices, and in particular to a cooling device and its control method that achieves efficient temperature control under extremely high heat flux through evaporative dissipation cooling technology under negative pressure in microchannels. Background Technology

[0002] With the rapid development of integrated circuits, high-power electronic devices, and high-energy-density power electronic systems, the heat flux density generated during the operation of electronic devices continues to rise, and the heat flux in local areas has increased from the traditional 10T to over 10T. 1 W / cm 2 Level upgraded to 10 2 W / cm 2 Level, or even approaching or exceeding 10 3 W / cm 2 Excessively high operating temperatures not only lead to performance degradation and decreased reliability of electronic devices, but may also cause irreversible failures. Therefore, breaking through the limitations of existing heat dissipation methods and developing new thermal management technologies for extreme high heat flux density conditions has become a critical issue that urgently needs to be addressed in the field of electronic devices.

[0003] In the current mainstream thermal management technology system, liquid cooling technology has received widespread attention due to its outstanding heat dissipation capacity. Among existing liquid cooling technologies, single-phase flow cooling is widely used due to its mature technology and stable operation. However, its heat dissipation capacity is essentially limited by the sensible heat transfer mechanism. Under high heat flux density conditions, it requires high flow rate and high flow velocity, resulting in a significant increase in pump power consumption. The system volume and energy consumption are difficult to further reduce, and the heat dissipation performance is gradually approaching its limit. Against this background, two-phase flow heat dissipation technology, which makes full use of the latent heat of phase change of the working fluid, has become an inevitable development direction for improving heat dissipation capacity. Among common two-phase heat transfer working fluids, water has significant advantages in engineering applications: it has a large latent heat of vaporization, high specific heat capacity, and excellent thermal conductivity, and its thermal properties are significantly better than most dielectric fluids and special working fluids. At the same time, water is widely available, inexpensive, and environmentally friendly, possessing outstanding economic and sustainable characteristics. Therefore, using water as the working fluid in a two-phase cold plate heat dissipation scheme can achieve significant heat dissipation effects and economic benefits. However, water has a high boiling point at normal pressure, which is usually higher than the safe operating temperature range of electronic devices, directly limiting its application in the field of two-phase cooling of electronic devices. To address this contradiction, a low-pressure or negative-pressure working environment can be constructed to effectively lower the boiling point of water, allowing it to undergo a stable phase change at a lower temperature, thus balancing efficient heat dissipation with device temperature control requirements.

[0004] Traditional two-phase cold plates mostly employ closed-loop systems, requiring an additional cold source to condense steam and circulate the working fluid. This results in complex systems with high operating costs. Considering the low-cost advantage of water as the working fluid, the economic viability of using a complex closed system would be compromised. Therefore, it is necessary to break away from the traditional closed-loop cold plate design and construct an open-loop evaporative cooling system. This system allows water to directly dissipate to the external environment as steam after evaporation and heat absorption, and maintains stable system operation through continuous cooling water replenishment. This significantly simplifies the system structure, reduces operating costs, and improves overall engineering applicability. Furthermore, under extremely high heat flux density conditions, water undergoes a violent phase change within the cold plate, instantly generating a large amount of steam. This can easily induce steam backflow within the cold plate, disrupting the original flow field and leading to deteriorated heat transfer or even operational instability. To suppress steam backflow and maintain the unidirectionality and stability of the two-phase flow, it is necessary to introduce rectifying structures at the evaporation section inlet or key locations to effectively guide and constrain the gas-liquid flow, ensuring stable heat transfer under high heat flux conditions from a flow organization perspective. Furthermore, in the actual operation of electronic devices, the heat load typically fluctuates with changes in operating conditions. A fixed-flow liquid supply method cannot simultaneously achieve both heat exchange efficiency and system stability under different heat load conditions. Therefore, there is an urgent need for a cooling method that can adaptively or dynamically adjust the liquid supply flow rate according to changes in heat load, in order to avoid performance and economic losses caused by localized drying or excessive liquid supply.

[0005] In summary, the key technical direction for achieving reliable thermal management of next-generation high heat flux density electronic devices is to fully utilize the excellent phase change heat transfer characteristics of water under low pressure conditions, construct a simple and cost-controllable open evaporative cooling system, and solve the problems of steam backflow and operating condition fluctuations under high heat flux density through flow rectification and flow rate regulation. This is also the key technical problem that this invention aims to solve. Summary of the Invention

[0006] The purpose of this invention is to address the problems of limited working fluid thermal properties, high cost, and unstable flow in current microchannel two-phase flow cooling systems when dealing with extreme high heat flux densities. This invention proposes a microchannel cooling device and control method. By constructing a stable negative pressure environment to drive water to boil at low pressure within the microchannel, utilizing a hydrophobic and permeable membrane to achieve efficient gas-liquid separation, and combining a microchannel structure with rectification function, this invention solves the problems of limited working fluid selection, unstable flow, and deteriorated heat transfer in microchannel two-phase flow cooling. Simultaneously, it achieves controllable adjustment of flow heat transfer, significantly improving the system's heat dissipation performance and operational economy under high heat flux conditions.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A microchannel cooling device includes a liquid supply unit, a cooling unit, and a control unit. The liquid supply unit continuously supplies coolant to the cooling unit. The cooling unit is arranged on the surfaces of various electronic components inside a cabinet, absorbing heat generated by the electronic components through the boiling and flowing coolant. The control unit regulates the pressure inside the cooling device and the pressure difference across the cooling unit, thereby driving the coolant to continuously flow into the cooling unit for heat exchange. The liquid supply unit includes a liquid supply tank for storing coolant and replenishing the tank as needed via a municipal water supply network. The cooling unit includes a parallel array of cold plates arranged on the surfaces of various heat sources inside the cabinet. Each cold plate consists of a microchannel structure for heat exchange and a rectifier structure upstream of the microchannel. The control unit includes a negative pressure regulating tank, a vacuum pump, and a pressure regulator. The system includes valves V1, V2, V3, and a controller. The negative pressure regulating tank is connected to the vacuum pump. The vacuum pump continuously extracts gas from the tank to maintain a stable low pressure and creates and maintains a certain pressure difference between the liquid supply unit and the negative pressure regulating tank. The pressure regulating valve V1 is located between the vacuum pump and the liquid supply unit, the throttle valve V2 is located between the liquid supply unit and the cooling unit, and the pressure regulating valve V3 is located between the negative pressure regulating tank and the ambient air. Driven by the pressure difference, the coolant spontaneously flows into the cooling unit, absorbs heat from the heat source, undergoes a phase change, forms a gas-liquid mixture, and flows to the negative pressure regulating tank. Subsequently, the gas in the negative pressure regulating tank is extracted by the vacuum pump and discharged to the external environment, thus dissipating heat to the external environment.

[0008] In this invention, the coolant can be water, methanol, ammonia, etc., but water is preferred. A vacuum pump actively regulates and stabilizes the pressure in the negative pressure regulating tank at a low level. This negative pressure state is rapidly transferred to the cooling unit through a sealed pipeline. Under this environment, the saturation temperature of the water is controlled within the safe operating temperature range of the electronic devices (e.g., below 70°C), thus overcoming the limitation that water's high boiling point at normal pressure is unsuitable for efficient heat dissipation at low temperatures. This allows the coolant to quickly reach saturation at the corresponding pressure when flowing through the heated microchannels, even if the heat source temperature is not high, triggering a stable boiling phase transition. The heat transfer mode thus changes from single-phase flow heat transfer dominated by sensible heat exchange to low-pressure boiling heat transfer dominated by latent heat absorption, fully utilizing the high latent heat of water, resulting in an order-of-magnitude increase in the heat transfer coefficient and significantly enhancing the system's cooling capacity to cope with instantaneous extreme high heat loads. Meanwhile, water, as a widely available, inexpensive, safe, and environmentally friendly working medium, not only avoids the high costs and potential environmental risks of special media such as fluorinated liquids, but also greatly reduces the long-term operation and maintenance costs of the system, thus improving the economic efficiency and sustainability of the technology.

[0009] To further enhance the system's operational reliability and long-term stability, a hydrophobic and breathable membrane is integrated into the negative pressure regulating chamber. This membrane is a porous fiber membrane with a hydrophobic surface modification treatment, exhibiting hydrophobic / superhydrophobic properties. Specifically, when a gas-liquid mixture containing droplets arrives at the membrane surface, due to the surface tension of the liquid on the hydrophobic surface, the liquid cannot wet and enter the membrane pores, instead forming a stable gas-liquid meniscus at the pore inlet. This interface effectively blocks the passage of liquid water. More importantly, under negative pressure, the liquid water at the interface continuously evaporates, and the resulting vapor molecules can freely diffuse through the pores to the other side of the membrane. Simultaneously, the vapor already present in the negative pressure regulating chamber is transported across the membrane almost unimpeded through the pores not covered by liquid. This structure achieves the functions of free gas phase transport and selective liquid phase blocking, thus completing efficient gas-liquid two-phase separation. This design eliminates the risk of liquid water being sucked into the vacuum pump pipeline, avoiding component corrosion and mechanical damage that may be caused by liquid entering the vacuum pump, and improving the durability and operational reliability of the core equipment.

[0010] To effectively suppress unstable phenomena such as reverse steam flow caused by intense boiling under high heat flux density within the cold plate, this invention designs a composite flow channel structure with rectification function inside the cold plate. This structure consists of a crescent-shaped rib located at the center line of the flow channel and Tesla-type flow channels symmetrically arranged on both sides, achieving low-resistance guidance for forward flow and high-resistance suppression for reverse flow. Specifically, when the coolant flows in along the designed flow direction (i.e., forward flow) from the convex front side of the crescent-shaped rib, its continuous and smooth arc profile provides good guiding effect for the incoming flow, allowing the fluid to flow smoothly around the rib surface with low overall flow resistance. However, when steam is generated due to intense local evaporation and attempts to flow in the reverse direction (i.e., flowing in from the concave front side of the crescent-shaped rib), the flow resistance characteristics change fundamentally. The concave structure of the crescent-shaped rib significantly impedes the incoming flow, forcing most of the reverse flow to deflect or even reverse its direction under the action of the concave surface. Furthermore, some fluid not directly impeded by the ribs enters the Tesla-type flow channels on both sides. These channels further guide and redirect the incoming fluid, increasing its flow path length and local resistance, thus synergistically enhancing the suppression of reverse flow. Therefore, the overall flow resistance of reverse flow is much greater than that of forward flow, creating an asymmetric flow resistance characteristic. Simultaneously, the overall flow channel of the rectifying structure gradually widens along the forward flow direction. This gradual widening design further reduces the flow resistance of forward flow and increases the flow resistance of reverse flow, strengthening the rectification effect. Under high heat flux conditions, the coolant rapidly vaporizes in the microchannel evaporation section, creating a vapor lock. Thanks to the aforementioned rectification structure, the tendency of steam to move upstream (reverse) is greatly suppressed, forcing the steam to move downstream (forward) with the mainstream and be discharged promptly. This mechanism effectively weakens the flow oscillation of the gas-liquid two-phase flow, stabilizes the two-phase flow pattern in the channel, and avoids heat transfer deterioration phenomena such as local "drying" and sudden increase in heat transfer resistance that may be caused by steam accumulation and flow reversal. It ensures that the system can maintain efficient and stable phase change heat transfer performance under extreme heat loads.

[0011] Based on the aforementioned microchannel cooling device, a corresponding control method is proposed. This method utilizes a controller to coordinate the operation of pressure regulating valve V1, throttle valve V2, and pressure regulating valve V3 to regulate the pressure and flow rate within the cooling device. Specifically, the method includes the following steps: Step 1, Basic Flow Control: By adjusting the valve opening of the pressure regulating valve V1 and the pressure regulating valve V3, the system pressure in the liquid supply tank and the negative pressure regulating tank is changed, thereby establishing a controllable driving pressure difference on both sides of the cooling unit and realizing the condition for the overall flow rate of the coolant flowing through the cooling unit. Step 2, Flow Stabilization Control: Before the coolant enters the cold plate array, the opening of the throttle valve V2 is adjusted to introduce controllable local flow resistance in the flow path, thereby increasing the proportion of the throttle section in the total system pressure drop, and achieving the following effects: (a) reducing the impact of pressure fluctuations caused by gas-liquid two-phase flow in the cold plate array on the overall flow stability of the system; (b) improving the uniformity of coolant flow distribution among multiple parallel cold plates; Step 3, Collaborative Optimization and Control: Based on the throttle valve V2 already set and providing stable flow resistance, the pressure regulating valves V1 and V3 are finely adjusted again in a collaborative manner. The driving pressure difference is precisely calibrated according to the real-time working load of the electronic devices, so that the coolant flow rate in the cooling unit matches the heat generation of the heat source, thereby achieving comprehensive optimization of heat dissipation efficiency, flow stability and cooling device reliability.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention proposes a microchannel cooling device and control method. By constructing a stable and controllable negative pressure environment, the water working medium undergoes a boiling phase change at a lower temperature within the microchannel. This transforms the traditional single-phase heat transfer mode, which is mainly based on sensible heat exchange, into a low-pressure two-phase boiling heat transfer mode, which is mainly based on the absorption of latent heat of phase change. The heat transfer coefficient is significantly improved, thereby effectively enhancing the heat dissipation capacity of the microchannel cold plate under extremely high heat flux density conditions. Simultaneously, using water as the cooling medium fully leverages its advantages of high latent heat of vaporization, high specific heat capacity, excellent thermal conductivity, wide availability, and low cost. While achieving highly efficient heat dissipation performance, it significantly reduces the system's operating and maintenance costs, balancing performance improvement with engineering economics.

[0013] 2. The introduction of a hydrophobic and breathable membrane structure enables effective separation of the gas and liquid phases. This hydrophobic and breathable membrane can prevent liquid water from passing through while allowing water vapor to smoothly cross the membrane and disperse, thereby preventing liquid working fluid from being sucked into the pipeline and entering the vacuum pump. This effectively prevents problems such as corrosion, hydraulic impact, and mechanical wear, and significantly improves the operational reliability and service life of the vacuum pump and the entire cooling system.

[0014] 3. By incorporating a composite flow channel structure with rectification function upstream of the microchannel, the forward flow resistance is significantly lower than the reverse flow resistance. Under high heat flux density conditions, this effectively suppresses steam backflow caused by violent boiling, preventing turbulent flow organization and localized heat transfer deterioration within the cold plate. This design helps stabilize the two-phase flow pattern within the microchannel, reduces flow oscillations, and prevents localized drying, thereby ensuring that the cooling device maintains efficient and stable heat transfer performance even under extreme heat loads.

[0015] 4. By coordinating the control of the pressure regulating valve and the throttle valve, precise regulation of the system's operating pressure and coolant flow rate is achieved. On the one hand, controllable and stable flow resistance can be introduced into the system to weaken the impact of pressure fluctuations caused by two-phase flow on the overall flow stability and improve the uniformity of flow distribution between parallel cold plates. On the other hand, the driving differential pressure can be dynamically adjusted according to the real-time changes in the heat load of electronic components, so that the coolant flow rate matches the heat load, thereby improving the system's operational stability and control flexibility under varying operating conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the cooling device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the cold plate structure and the forward flow of coolant in an embodiment of the present invention; Figure 3 This is a schematic diagram of the reverse flow of coolant inside the cold plate according to an embodiment of the present invention; Wherein: 1-Supply tank; 2-Coolant; 3-Cold plate; 4-Negative pressure regulating tank; 5-Hydrophobic and breathable membrane; 6-Vacuum pump; 7-Pressure regulating valve V1; 8-Throttle valve V2; 9-Pressure regulating valve V3; 10-Coolant flow direction; 11-Steam flow direction; 12-Controller; 13-Cabinet; 301-Coolant inlet; 302-Coolant outlet; 303-Tesla-type flow channel; 304-Crescent-shaped rib; 305-Microchannel; 306-Forward flow; 307-Reverse flow. Detailed Implementation

[0017] To enhance understanding of the present invention, we will now describe it in further detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art. This embodiment is only used to explain the present invention and does not constitute a limitation on the scope of protection of the present invention.

[0018] Figure 1 A specific embodiment of a microchannel cooling device is shown, including a liquid supply unit, a cooling unit, and a control unit. The liquid supply unit continuously supplies coolant to the cooling unit, which is arranged on the surfaces of various electronic components inside the cabinet to absorb the heat generated by the electronic components. The control unit regulates the system pressure and flow rate to drive the coolant to flow stably through the cooling unit and achieve phase change dissipation heat dissipation.

[0019] Specifically, the coolant supply unit includes a coolant supply tank 1, which stores coolant, preferably water. The coolant supply tank 1 can be connected to an external water source via a tap water network to replenish the coolant during system operation based on coolant consumption. The coolant supply tank 1 is connected to the cooling unit and the negative pressure regulating tank 4 via pipelines, creating a stable driving pressure difference across the system. The cooling unit includes an array of parallel-arranged cold plates 3, which are installed on the surfaces of various electronic components inside the cabinet 13 to directly absorb the heat generated during operation. The cold plates 3 are connected in parallel to accommodate the heat dissipation needs of multiple heat source electronic components. The control unit includes the negative pressure regulating tank 4, a vacuum pump 6, a pressure regulating valve V17, a throttle valve V28, a pressure regulating valve V39, and a controller 12. The negative pressure regulating tank 4 is connected to the vacuum pump 6 via pipelines, which continuously extracts gas from the negative pressure regulating tank 4 to maintain a stable low-pressure state inside. This low-pressure state is transmitted to the cooling unit through a closed pipeline, significantly reducing the saturation temperature of the coolant within the microchannels. A hydrophobic and breathable membrane 5, a porous fiber membrane with a hydrophobic surface treatment, is installed inside the negative pressure regulating chamber 4. When the gas-liquid mixture enters the negative pressure regulating chamber 4, liquid water cannot wet the surface of the hydrophobic and breathable membrane 5 and pass through the membrane pores, while water vapor can easily diffuse through the pores to the other side of the membrane under the pressure difference. This achieves effective separation of the gas and liquid phases, preventing liquid water from being sucked into the pipeline by the vacuum pump 6 and avoiding damage to the vacuum pump.

[0020] Figure 2 and Figure 3A schematic diagram of the cold plate structure and its internal flow is provided. Each cold plate 3 consists of a microchannel 305 and a rectifier structure located upstream of the microchannel. The microchannel 305 is used to achieve efficient heat exchange between the coolant and the heat source. It forms a narrow flow channel inside to increase the heat exchange area per unit volume and enhance the phase change heat transfer process. A rectifier structure is set on the inlet side of the microchannel 305. This rectifier structure consists of a meniscus-shaped rib 304 located at the center of the flow channel and Tesla-type flow channels 303 symmetrically arranged on both sides of it. The rectifier structure is arranged in a gradually expanding manner along the forward flow direction of the coolant. When the coolant flows in the designed direction (forward flow 306), the fluid enters from the convex front side of the meniscus-shaped rib 304. The smooth arc-shaped contour of the meniscus guides the flow, allowing the fluid to flow smoothly around the rib surface and enter the microchannel 305. At this time, the overall flow resistance is small. When high heat flux density triggers violent evaporation within the system, generating steam that attempts to flow in the opposite direction (reverse flow 307), the fluid enters from the concave, upstream side of the meniscus rib 304. The concave structure significantly impedes the incoming flow, causing most of the reverse fluid to deflect or reverse. The reverse fluid not directly impeded enters the Tesla-type flow channels 303 on both sides of the meniscus, undergoing multiple directional changes under the guidance of these channels, significantly increasing the flow path length and friction resistance. Through the synergistic effect of these structures, the reverse flow resistance is much greater than the forward flow resistance, effectively suppressing steam backflow.

[0021] During system operation, controller 12 first establishes a stable pressure difference between the supply tank 1 and the negative pressure regulating tank 4 by adjusting pressure regulating valves V17 and V39. Driven by this pressure difference, the coolant spontaneously flows into the cooling unit and enters each cold plate 3 in the forward flow direction. When the coolant flows within the microchannel structure 305, it exchanges heat with the surface of the electronic devices and absorbs heat. When the coolant temperature reaches the saturation temperature at the corresponding pressure, a boiling phase change occurs, forming a gas-liquid mixture. When the gas-liquid mixture flows through the rectifying structure, the reverse flow tendency of the vapor is significantly suppressed, and the gas and liquid phases enter the negative pressure regulating tank 4 in the forward flow direction. The gas phase is discharged through the hydrophobic and breathable membrane 5 and is extracted from the system by the vacuum pump 6, eventually being discharged into the external environment to dissipate heat; the liquid phase circulates within the system or is replaced by continuously replenished coolant.

[0022] Before the coolant enters the cold plate array, a controllable local flow resistance is introduced into the system by adjusting the opening of the throttling valve V28. This increases the proportion of the throttling section in the total system pressure drop, thereby reducing the impact of pressure fluctuations caused by the gas-liquid two-phase flow in the microchannel on the overall flow stability and improving the uniformity of flow distribution among the parallel cold plates. Based on this, the controller 12 coordinates the adjustment of the pressure regulating valves V17 and V39 according to the real-time heat load of the electronic components, accurately calibrating the system driving pressure difference. This allows the coolant flow rate to be dynamically adjusted according to changes in heat load, thereby achieving comprehensive optimization of heat dissipation performance, flow stability, and system reliability.

[0023] The above specific embodiments are only for illustrating the technical concept and structural features of the present invention, and are intended to enable those skilled in the art to implement them. However, the above content does not limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit and essence of the present invention should fall within the scope of protection of the present invention.

Claims

1. A microchannel cooling device, characterized in that: The system includes a coolant supply unit, a cooling unit, and a control unit. The coolant supply unit continuously supplies coolant to the cooling unit. The cooling unit is arranged on the surfaces of various electronic components inside the cabinet, absorbing the heat generated by the electronic components through the boiling and flowing coolant. The control unit regulates the pressure difference between the cooling unit and the cooling unit, thereby driving the coolant to continuously flow into the cooling unit for heat exchange. The coolant supply unit includes a coolant tank for storing coolant and replenishing it as needed via a municipal water supply network. The cooling unit includes a parallel array of cold plates arranged on the surfaces of various heat sources inside the cabinet. Each cold plate consists of a microchannel structure for heat exchange and a rectifier structure upstream of the microchannel. The control unit includes a negative pressure regulating tank, a vacuum pump, a pressure regulating valve V1, and a [missing information - likely a valve name or component]. The system includes a flow valve V2, a pressure regulating valve V3, and a controller. The negative pressure regulating tank is connected to the vacuum pump. The vacuum pump continuously extracts gas from the tank to maintain a stable low pressure and creates and maintains a certain pressure difference between the liquid supply unit and the negative pressure regulating tank. The pressure regulating valve V1 is located between the vacuum pump and the liquid supply unit, the flow regulating valve V2 is located between the liquid supply unit and the cooling unit, and the pressure regulating valve V3 is located between the negative pressure regulating tank and the atmospheric environment. Driven by the pressure difference, the coolant spontaneously flows into the cooling unit, absorbs heat from the heat source, undergoes a phase change, forms a gas-liquid mixture, and flows to the negative pressure regulating tank. Subsequently, the gas in the negative pressure regulating tank is extracted by the vacuum pump and discharged to the external environment, thus dissipating heat to the external environment.

2. The microchannel cooling device according to claim 1, characterized in that: The coolant is water, methanol, or ammonia.

3. The microchannel cooling device according to claim 1, characterized in that: The coolant is water. By controlling the pressure in the negative pressure regulating tank, the pressure is transmitted to the cooling unit, reducing the saturation temperature of the water to below the safe operating temperature of the electronic devices. This causes the heat transfer mode of the water in the microchannel to change from atmospheric pressure single-phase heat transfer to low-pressure two-phase boiling heat transfer, which greatly improves the heat transfer coefficient and thus significantly enhances the cooling performance of the cooling unit in the face of extreme high heat loads.

4. The microchannel cooling device according to claim 1, characterized in that: The negative pressure regulating box is equipped with a hydrophobic and breathable membrane, which is a porous fiber membrane. The surface of the membrane is hydrophobically treated to prevent liquid from passing through while allowing vapor to pass through the membrane pores and diffuse across the membrane. The original vapor in the negative pressure regulating box can diffuse directly to the other side of the membrane through the pores that are not blocked by liquid, thereby achieving efficient gas-liquid separation and preventing liquid water from being drawn into the pipeline by the vacuum pump and entering the vacuum pump, causing damage to it.

5. The microchannel cooling device according to claim 1, characterized in that: The cold plate features a flow-rectifying structure before the coolant enters the microchannels, including meniscus-shaped ribs and Tesla-type flow channels. The meniscus-shaped ribs are positioned at the center of the flow channels, and the Tesla-type flow channels are symmetrically arranged on both sides of the meniscus-shaped ribs. When the fluid sweeps across the surface of the meniscus-shaped ribs from the convex, forward-facing side, its arc-shaped outer contour guides the flow, allowing the fluid to flow along the rib surface and smoothly bypass the meniscus-shaped ribs. At this point, the flow resistance is low, and this flow direction is defined as forward flow. When the fluid sweeps across the surface of the meniscus-shaped ribs from the concave, forward-facing side, the meniscus-shaped ribs... The structure significantly impedes flow, deflecting or even reversing the flow direction of most incoming streams. Streams not impeded by the meniscus ribs flow into the Tesla-type channels on either side of the ribs, where the flow direction is deflected and reversed. At this point, the flow resistance along the flow path is high, making it difficult for the fluid to flow in this direction; this flow direction is defined as reverse flow. Furthermore, the flow channels of the rectifying structure gradually expand along the forward flow direction. This gradual expansion design further reduces the forward flow resistance and increases the reverse flow resistance, thus enhancing the rectifying effect.

6. The microchannel cooling device according to claim 5, characterized in that: The coolant flows into the microchannel in the forward flow direction. When the microchannel faces a large heat flow, the coolant evaporates violently and generates a large amount of steam, which is prone to gas-liquid backflow. However, under the action of the rectification structure, the backflow of steam is suppressed, thus avoiding the heat transfer deterioration that may occur in the cold plate due to the backflow of steam.

7. A method for regulating the microchannel cooling device according to any one of claims 1-6, characterized in that, The controller coordinates the operation of pressure regulating valve V1, throttle valve V2, and pressure regulating valve V3 to regulate the pressure and flow rate within the cooling device.

8. The control method according to claim 7, characterized in that, Specifically, the following steps are included: Step 1, Basic Flow Control: By adjusting the valve opening of the pressure regulating valve V1 and the pressure regulating valve V3, the system pressure in the liquid supply tank and the negative pressure regulating tank is changed, thereby establishing a controllable driving pressure difference on both sides of the cooling unit and realizing the condition for the overall flow rate of the coolant flowing through the cooling unit. Step 2, Flow Stabilization Control: Before the coolant enters the cold plate array, the opening of the throttle valve V2 is adjusted to introduce controllable local flow resistance in the flow path, thereby increasing the proportion of the throttle section in the total system pressure drop, and achieving the following effects: (a) reducing the impact of pressure fluctuations caused by gas-liquid two-phase flow in the cold plate array on the overall flow stability of the system; (b) improving the uniformity of coolant flow distribution among multiple parallel cold plates; Step 3, Collaborative Optimization and Control: Based on the throttle valve V2 already set and providing stable flow resistance, the pressure regulating valves V1 and V3 are finely adjusted again in a collaborative manner. The driving pressure difference is precisely calibrated according to the real-time working load of the electronic devices, so that the coolant flow rate in the cooling unit matches the heat generation of the heat source, thereby achieving comprehensive optimization of heat dissipation efficiency, flow stability and cooling device reliability.

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