An immersion phase change heat dissipation device and method based on partition adaptation

Abstract

This invention provides an immersion phase change heat dissipation device and method based on partitioned adaptation, relating to the field of high heat flux density heat dissipation technology. It includes: an immersion cooling chamber with a gas phase zone and a liquid phase zone formed sequentially from top to bottom; a heat-generating element to be cooled is arranged in the liquid phase zone, which is filled with a low-boiling-point insulating cooling medium; a pulsating heat pipe array composed of multiple closed-loop pulsating heat pipes, each arranged vertically, and from top to bottom consisting of a condensation section, an adiabatic section, and an evaporation section; the evaporation section is located within the gas phase zone, while the condensation and adiabatic sections extend to the outside of the chamber; a flow guide shroud, located in the gas phase zone between the evaporation section and the liquid surface of the cooling medium, has a flared, two-section truncated quadrangular truncated pyramid structure, with its lower opening serving as a steam inlet, positioned opposite the liquid surface of the cooling medium in the liquid phase zone; steam outlet holes on the upper sidewall are arranged facing the evaporation section of the pulsating heat pipes; this invention achieves uniform steam distribution, efficient condensation, reliable vapor-liquid separation, and long-term stable operation within the gas phase zone.

Description

Technical Field

[0001] This invention relates to the field of high heat flux density heat dissipation technology, specifically to two-phase immersion phase change cooling and pulsating heat pipe high-efficiency heat transfer technology, and is particularly suitable for closed phase change immersion heat dissipation systems for high heat flux density electronic and electrical equipment such as big data center servers, high-performance computing devices, and high-power energy storage modules. Background Technology

[0002] With the rapid development of high-performance computing and artificial intelligence technologies, the computing power density of data centers continues to rise, and the heat flux density of electronic devices has exceeded the heat dissipation limits of traditional air-cooling technologies. Two-phase immersion liquid cooling technology, with its extremely high heat dissipation efficiency and power density compatibility, has become a key technological approach to solving the problem of high heat flux density heat dissipation. In this technology, the cooling medium absorbs heat and vaporizes to form steam. The steam condenses and flows back within the gas phase region of a sealed cavity, and its efficiency and stability directly determine the performance of the entire heat dissipation system.

[0003] Existing immersion liquid cooling systems have significant deficiencies in their heat dissipation design in the gas phase region. Uneven distribution of steam as it rises naturally within the cavity can easily lead to load imbalance in the condensation unit, creating localized hotspots. Existing flow guiding structures are functionally limited, failing to balance efficient steam convergence and uniform diffusion, and are prone to generating eddies, increasing flow resistance, and exacerbating the mutual interference between the vapor and liquid phases. The droplets formed by steam condensation are difficult to detach quickly from the condensation surface, easily forming a heat-inducing liquid film, severely impacting condensation efficiency. The rising steam flow can even obstruct and carry droplets back, leading to condensate backflow and even liquid blockage, severely disrupting the stability of the phase change cycle. Furthermore, the superhydrophobic surfaces used to improve condensation efficiency are prone to degradation under harsh environments of long-term high temperatures and working fluid scouring, transforming efficient droplet condensation into inefficient film condensation, causing the system's heat dissipation performance to decline over time. Simultaneously, the components within the cooling system are typically designed independently, lacking coordinated optimization based on the overall flow and thermal fields. Active cooling components also struggle to dynamically adjust according to the heat load, resulting in additional energy consumption.

[0004] Therefore, existing immersion cooling solutions suffer from shortcomings such as uneven vapor distribution and unbalanced load of condensing units, poor vapor-liquid separation and condensate backflow, insufficient long-term stability of superhydrophobic surfaces, and lack of coordinated optimization and dynamic control of system components. As a result, the heat dissipation efficiency and operational stability of the vapor phase region cannot meet the application requirements of high reliability and high efficiency. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes an immersion phase change heat dissipation device and method based on zone adaptation, which achieves uniform vapor distribution, efficient condensation, reliable vapor-liquid separation, and long-term stable operation within the gas phase zone.

[0006] According to some embodiments, the present invention adopts the following technical solution: An immersion phase change heat dissipation device based on partition adaptation includes: The immersion cooling chamber is a sealed pressure-bearing shell. Its interior is divided into a gas phase zone and a liquid phase zone from top to bottom. The liquid phase zone is where the heating elements to be cooled are arranged and filled with a low-boiling-point insulating cooling medium. The pulsating heat pipe array consists of multiple closed-loop pulsating heat pipes, each arranged vertically, and from top to bottom, it consists of a condensation section, an adiabatic section, and an evaporation section; wherein, the evaporation section is located within the gas phase region, and the condensation section and the adiabatic section extend to the outside of the housing. The flow guide shroud is located in the gas phase zone between the evaporation section and the cooling working fluid liquid surface. It has a flared, two-section truncated quadrangular truncated structure. Its lower end opening serves as a steam inlet and is positioned opposite to the cooling working fluid liquid surface in the liquid phase zone to collect rising steam. The steam outlet holes on its upper sidewall are arranged facing the evaporation section of the pulsating heat pipe to uniformly guide the steam to the surface of the evaporation section.

[0007] According to some embodiments, the present invention adopts the following technical solution: An immersion phase change heat dissipation method based on partition adaptation includes: The heat generated by the cooling heating element is transferred to the low-boiling-point insulating cooling medium in the liquid phase region. After the cooling medium absorbs heat and boils, it generates steam, which then rises into the gas phase region. Steam enters the interior of the guide shroud through the lower inlet, flows upward along the guide shroud, and is evenly sprayed onto the surface of the evaporation section of the pulsating heat pipe through the steam outlet holes on the upper side wall. Steam condenses and releases heat on the surface of the evaporation section. The released condensation heat is transferred to the working fluid inside the pulsating heat pipe. After the working fluid absorbs heat, it forms a two-phase pulsating cycle of vapor and liquid, which transfers heat to the condensation section and dissipates it to the outside. The cooling fluid droplets formed by condensation naturally flow back to the liquid phase region along the outer wall of the guide shroud and the outer wall of the evaporation section of the pulsating heat pipe, completing the circulation of the cooling fluid.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves active control of the steam flow path during immersion phase change cooling by placing the evaporation section of the pulsating heat pipe within the gas phase region and coordinating it with a structured arrangement of a flow guide shroud. The flow guide shroud adopts a flared, two-section truncated quadrangular prism structure, with its lower opening facing the liquid surface. This effectively collects the rising steam generated by the boiling of the heating element, preventing disordered steam diffusion within the gas phase region. The steam outlet holes on the upper sidewall are arranged towards the evaporation section of the pulsating heat pipe, uniformly guiding the collected steam to the surface of each heat pipe evaporation section. This allows the evaporation section to directly contact the high-temperature steam for heat exchange, enhancing the heat input at the evaporation end of the pulsating heat pipe. This zoned adaptation design prioritizes the use of steam generated by immersion boiling to drive the pulsating circulation of the working fluid inside the pulsating heat pipe. The condensation and adiabatic sections of the pulsating heat pipe extend to the outside of the casing, efficiently transferring heat to the external environment. This improves the overall heat transfer efficiency and heat dissipation capacity of the device without adding additional power components. Attached Figure Description

[0009] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0010] Figure 1 This is a structural diagram of an immersion phase change heat dissipation device based on partition adaptation, as shown in Example 1.

[0011] Figure 2 This is a schematic diagram of the pulsating heat pipe array in Example 1.

[0012] Figure 3 This is an enlarged view of the single pulsating heat pipe in Example 1.

[0013] Figure 4 This is a structural diagram of the fairing in Example 1.

[0014] Figure 5 This is a structural diagram of the flow equalization and guiding section of the circular through hole in Example 1.

[0015] Figure 6 This is a structural diagram of the flow equalization and guiding section of the elongated oval hole in Example 1.

[0016] Figure 7 This is a structural diagram of the flow equalization and guiding section of the irregular-shaped hole in Example 1.

[0017] Among them, 1-server, 2-liquid phase zone, 3-cabinet, 4-polyurethane insulation layer, 5-gas phase zone, 6-pulsating heat pipe evaporation section, 7-speed sensor, 8-pulsating heat pipe condensation section, 9-corrugated fins, 10-closed pulsating heat pipe, 11-temperature sensor, 12-controller, 13-heat sink, 14-axial fan, 15-pulsating heat pipe insulation section, 16-flow guide, 17-blower plate, 18-liquid level sensor. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0021] Example 1 One embodiment of the present invention provides an immersion phase change heat dissipation device based on partition adaptation, comprising: The immersion cooling chamber is a sealed pressure-bearing shell. Its interior is divided into a gas phase zone and a liquid phase zone from top to bottom. The liquid phase zone is where the heating elements to be cooled are arranged and filled with a low-boiling-point insulating cooling medium. The pulsating heat pipe array consists of multiple closed-loop pulsating heat pipes, each arranged vertically, and from top to bottom, it consists of a condensation section, an adiabatic section, and an evaporation section; wherein, the evaporation section is located within the gas phase region, and the condensation section and the adiabatic section extend to the outside of the housing. The flow guide shroud is located in the gas phase zone between the evaporation section and the cooling working fluid liquid surface. It has a flared, two-section truncated quadrangular truncated structure. Its lower end opening serves as a steam inlet and is positioned opposite to the cooling working fluid liquid surface in the liquid phase zone to collect rising steam. The steam outlet holes on its upper sidewall are arranged facing the evaporation section of the pulsating heat pipe to uniformly guide the steam to the surface of the evaporation section.

[0022] As one embodiment, the present invention provides an immersion phase change heat dissipation device based on partition adaptation, such as... Figure 1 As shown, it includes: The immersion cooling chamber (3) is a sealed pressure-bearing shell, with a gas phase zone (5) and a liquid phase zone (2) formed from top to bottom inside.

[0023] The liquid phase region (2) is arranged with heating elements to be cooled, which is the server (1) in this embodiment, and is filled with a low boiling point insulating cooling medium. The medium is preferably a hydrofluoroether (HFE) type fluorinated liquid with a boiling point of 40℃~100℃. It has insulation, non-flammability, low viscosity, high phase change heat transfer capability, and excellent matching with the server (1).

[0024] The gas phase zone (5) is used to collect the steam formed by the vaporization of the cooling working fluid when heated; the inner wall of the box is covered with a polyurethane insulation layer (4) to reduce the heat loss of the box to the outside.

[0025] In the specific implementation, a gravity flow guide surface, i.e., a 5° to 8° inclined surface, is set on the inner wall of the vapor phase zone (5) of the cooling chamber, which is consistent with the upper inclination angle of the guide shroud (16) to guide the condensate to flow smoothly back along the inner wall, effectively avoiding local liquid accumulation and vapor-liquid flow collision; a polyurethane foam insulation layer (4) is laid on the inner wall to block cold bridges, reduce system cooling loss, and ensure that the outer wall temperature is higher than the ambient air dew point, thereby preventing condensation; in the area corresponding to the evaporation section (6) of the pulsating heat pipe, the insulation layer (4) adopts a local avoidance opening design, with the opening size slightly larger than the outer diameter of the heat pipe, to provide a flow gap for steam. This design achieves three advantages: First, it avoids the insulation material from wrapping the heat pipe, ensuring the heat exchange efficiency of the heat pipe; second, it maintains the continuity of the overall inclination angle of the inner wall; third, it maximizes the preservation of the structural integrity of the insulation layer, and the overall processing and installation are simple and the processability is excellent.

[0026] Specifically, the inclined surface begins at the top of the liquid phase zone (the upper limit of the server installation height), extends only within the gas phase zone, and its lowest point points towards the liquid phase zone. The liquid phase zone where the server is located maintains a vertical wall, which does not affect server installation and plugging / unplugging, achieving full-area condensate backflow without accumulation. The cooling fluid condensate can naturally flow back to the liquid phase zone along the inclined surface of the guide shroud and the wall of the pulsating heat pipe; the gas phase vapor is mainly guided upward by the central truncated square guide shroud, with a small amount of vapor flowing through the gap between the guide shroud and the enclosure. Overall, natural vapor-liquid separation and smooth flow are achieved, eliminating the need for additional liquid-blocking structures to prevent vapor backflow. The structure is simple and reliable, suitable for long-term stable operation of liquid-cooled data centers.

[0027] The enclosure (3) is made of pressure-bearing metal material, preferably stainless steel, aluminum alloy or carbon steel, to ensure that the sealing performance and structural strength meet the requirements under phase change pressure.

[0028] The heat sink (13) is located outside the pulsating heat pipe condensation section (8) and the fin (9) assembly, forming a closed heat dissipation cavity. The heat sink (13) is made of lightweight alloy material. The air inlet and outlet are symmetrically opened on both sides of the box to ensure smooth airflow. The heat dissipation component uses two axial flow fans (14), which are symmetrically installed at the air inlet positions on the left and right ends of the heat sink (13). Each fan corresponds to one side of the air inlet. The fans are adapted to the condensation load requirements and adopt a speed control mode. The speed can be automatically adjusted in real time according to the condensation end temperature to balance the heat dissipation efficiency and energy consumption control requirements.

[0029] The pulsed heat pipe array adopts a standardized modular design and is a plug-and-play heat exchange module. Its structure is compatible with 19 / 21-inch standard server racks in data centers, and it can be directly assembled and used. It is easy to assemble and disassemble, has strong versatility, and can adapt to the installation and deployment requirements of different server rack specifications. The heat exchange module consists of multiple closed pulsed heat pipes (10). Each heat pipe is arranged parallel and equidistantly in the vertical direction. The number of heat pipes can be flexibly increased or decreased according to the power density of the server rack and the actual heat dissipation load, with excellent adaptability and scalability.

[0030] In specific implementation methods, such as Figure 2 As shown, multiple groups of pulsating heat pipes form a pulsating heat pipe array, which is uniformly arranged in an array within the cooling box. Each pipe forms a group, and each group is continuously bent 12 times. The spacing between two adjacent groups of pulsating heat pipes is 10-20 mm, preferably 15 mm, to ensure smooth steam flow and effective condensate return, thereby improving the overall heat dissipation uniformity. The pulsating heat pipe array is centrally symmetrically arranged, and has a square configuration when viewed from above, forming an optimal spatial fit with the truncated quadrangular shroud. The top of the shroud is closed, with steam outlet holes only opened on the four side walls of the upper half.

[0031] Based on the distribution characteristics of the steam flow field within the cooling box (high-speed jet region and free diffusion region), the spatial orientation and arrangement of the pulsating heat pipe array are actively adapted to achieve a balance between local enhancement and global smooth flow. All pulsating heat pipes that can be directly contacted by the steam jet from the steam outlet of the flow guide are inclined at a small angle (20°–30°) towards the flow guide and steam outlet, with their evaporation ends facing the vertical direction; the outer pulsating heat pipes not directly covered by the steam jet remain vertically arranged.

[0032] This tilted arrangement involves only a small local angle adjustment at the evaporator end, without altering the main flow channel and curved structure of the pulsating heat pipe. It will not adversely affect the heat pipe's pulsating circulation characteristics or heat transfer performance. Simultaneously, it allows the evaporator end to be closer to the steam outlet, increasing the direct contact area with the jet of steam and significantly enhancing steam condensation. The tilted pipe wall allows gravity to guide the condensate inside the heat pipe back to the evaporator section more smoothly, reducing the risk of liquid blockage and improving the heat pipe's operational stability. The vertical heat pipe on the outer side provides ample space for steam to diffuse outwards, reducing flow resistance.

[0033] The single pulsed heat pipe (10) is made of stainless steel or copper tubing. The tube body is a vacuum-sealed structure and is arranged vertically. From top to bottom, it consists of a condensation section (8), an insulation section (15), and an evaporation section (6), thus achieving partitioned arrangement of hot and cold sections and eliminating heat crosstalk.

[0034] Among them, the evaporation section (6) is completely placed in the gas phase zone (5) of the immersion cooling box, and directly contacts the steam generated by the vaporization of the cooling working medium, so as to efficiently complete the condensation phase change heat transfer; the condensation section (8) and the insulation section (15) extend out of the immersion cooling box (3) to achieve physical isolation between the hot and cold ends; the outer wall of the condensation section (8) is integrally formed with corrugated heat dissipation fins (9), which greatly increases the heat exchange area on the air side and enhances the external heat dissipation efficiency.

[0035] The pulsating heat pipe (10) is filled with a customized mixed working fluid. The thermal properties of the working fluid are matched with the fluorinated cooling working fluid in the box to ensure efficient and stable phase change cycle. The working fluid filling rate is strictly controlled within the range of 30% to 60% to balance the heat pipe's start-up performance and heat exchange capacity. The inner wall of the heat pipe is mirror polished to effectively reduce the flow resistance of the gas-liquid two-phase working fluid inside the pipe, reduce pulsating operation losses, ensure rapid start-up and continuous stable operation of the pulsating heat pipe, and avoid problems such as liquid blockage and heat transfer deterioration.

[0036] In its specific implementation, the pulsating heat pipe (10) adopts an internal and external partitioned layout. Its evaporation section (6) is located in the gas phase zone (5) inside the cavity, and the structure is optimized for steam condensation heat exchange: the heat exchange area is increased and the flow channel arrangement is optimized to suppress liquid film blockage and gas film encapsulation, and to enhance phase change heat exchange and vapor phase mass transfer. The adiabatic section (15) and the condensation section (8) extend to the outside of the cavity to achieve complete physical isolation between the hot and cold ends, avoid thermal crosstalk, and improve system stability.

[0037] Figure 3 This is an enlarged view of a single pulsating heat pipe. The blank area at the top represents the condensation section and the adiabatic section. The outer wall of the evaporation section (6) is equipped with a three-layer composite enhanced condensation structure, which, from the inside out, consists of: a high thermal conductivity copper foil base layer, a gradient capillary microstructure layer, and a superhydrophobic modified layer. The layers are tightly bonded together with a high thermal conductivity adhesive to eliminate contact thermal resistance. Among them, such as Figure 3 As shown, the densely packed, crisscrossing sections represent the gradient capillary microstructure layer, which is a nanoscale array of radial and axial grooves that combines capillary conduction and enhanced heat transfer.

[0038] The gradient capillary microstructure layer adopts a gradient capillary reflux structure on the outer wall of the heat pipe. This structure consists of radial and axial composite microgrooves laser-etched on the outer wall of the evaporation section of the pulsating heat pipe: the axial grooves extend along the vertical direction of the heat pipe, and the radial grooves are evenly distributed in a ring. The groove density gradually increases from the top to the bottom of the heat pipe. The synergistic effect of capillary gradient and gravity is used to achieve directional and rapid condensate drainage, ensuring that the condensate has a downward driving force at both the top and bottom of the evaporation section, and avoiding liquid accumulation at the top.

[0039] The superhydrophobic modified layer is a micro-nano hierarchical rough structure prepared by femtosecond laser processing. The surface is coated with a microcapsule self-healing fluorosilane coating to achieve and maintain efficient droplet condensation and significantly improve the condensation heat transfer coefficient.

[0040] In the microcapsule self-healing fluorosilane coating, the repair agent encapsulated within the microcapsules is a fluorosilane prepolymer consistent with the coating matrix. It is stably encapsulated within the capsules, with no leakage or loss before triggering. When microcracks develop on the coating surface due to long-term erosion by working fluid vapor or particle abrasion, the crack propagation punctures the corresponding microcapsule. The internal repair agent rapidly fills the crack under capillary force and autonomously cross-links and cures at the operating temperature in the gas phase region, achieving in-situ repair. This self-triggered, self-healing process requires no external intervention or system shutdown, ensuring the long-term stability of the superhydrophobic condensation interface and thus maintaining the long-term reliability of the module's heat dissipation performance.

[0041] This embodiment adopts a synergistic cooling method with passive condensation as the main method and active heat dissipation as the auxiliary method. The external condensing section (8) of the pulsating heat pipe adopts a corrugated finned tube structure, which greatly increases the heat exchange area of ​​the condensing end and enhances the heat exchange efficiency on the air side. Cooling fans, namely axial fans (14), are symmetrically arranged on the left and right sides of the condensing section (8) to form a bidirectional cross-flow cooling field, which evenly blows the corrugated finned tube, quickly removes the heat from the condensing end, solves the heat dissipation bottleneck of the external condensing end, ensures efficient condensation and reflux of the working fluid inside the heat pipe, and maintains the stable operation of the pulsating heat pipe. When the cooling fans are running, the fans on both the left and right sides synchronously guide the outside cold air into the closed heat dissipation cavity through the corresponding air inlets. The cold air flows evenly through the fin assembly and the condenser end pipe, and completes heat exchange and temperature rise with the heat transferred to the condenser end. The heated air is discharged through the air outlet of the box, realizing the dissipation of heat to the outside. By symmetrically supplying air from both the left and right ends, the airflow distribution in the heat dissipation cavity is ensured to be uniform, avoiding the problem of local overheating of the fins. The controller collects the temperature of the cavity, condenser end and ambient temperature in real time, and adaptively adjusts the fan speed, which greatly reduces energy consumption while ensuring the cooling effect, and achieves efficient, low-noise and adaptive closed immersion cooling.

[0042] The flared baffle (16) is customized to meet the requirements of steam flow and vapor-liquid separation in the gas phase zone of the system. It adopts a two-section truncated quadrangular truncated structure and has an overall flared shape with a smaller top and a larger bottom. The top is closed, the baffle sidewall is open with a flow guide hole near the top, and the bottom is the steam inlet, which fits the internal layout and steam flow characteristics of the sealed immersion cavity.

[0043] The main body of the flow guide (16) is made of 304 stainless steel. This material has excellent high temperature resistance and fluorinated liquid corrosion resistance, as well as sufficient structural rigidity and mechanical strength. It can adapt to the harsh working conditions of high temperature steam scouring and working fluid erosion in the gas phase zone, meet the long-term stable operation requirements of the heat dissipation system, and is not prone to deformation, rust failure, etc., ensuring the long-term durability of the flow guide structure.

[0044] In its specific implementation, the flow guide is a two-section truncated quadrangular flared structure. This square-pyramidal structure is custom-designed to meet the flow guidance, disturbance, and vapor-liquid separation requirements of the outer gas phase zone of the vertical pulsating heat pipe array evaporation section. Unlike conventional constant-angle flow guide components, it adopts a segmented, differentiated-angle design, combining the three core advantages of flow guidance and equalization, condensation reflux, and vapor-liquid separation. Specifically: Firstly, the structural inclination angles are arranged differently.

[0045] like Figure 4 As shown, the flow guide is divided into a closed flow guide section and a flow equalization flow guide section from bottom to top. The whole structure maintains the shape of a truncated quadrangular prism without a sharp cone top, which can effectively avoid the hidden dangers of local airflow turbulence.

[0046] The lower closed guide section accounts for 2 / 3 of the total height, with its sidewalls inclined at a 35° angle to the vertical direction. It adopts a solid, sloping structure without through holes to achieve efficient steam gathering and directional flow, preventing disorderly steam dissipation. The upper flow equalization guide section has its sidewalls inclined at a small angle of 6° to 8° to the vertical direction, which is significantly narrower than the lower section's angle. This allows for smooth and uniform steam diffusion, ensuring that the airflow fully covers the pulsating heat pipe evaporation section and significantly improving heat exchange uniformity. The upper and lower conical surfaces are smoothly transitioned by arcs, with no bends or sudden expansions in the generatrix, reducing flow resistance and eliminating steam separation and eddy current problems. The vertical edges of the truncated pyramid are conventional structural angles, which do not affect the vertical upward steam flow and do not require additional rounding treatment, balancing the guiding effect with ease of processing.

[0047] Secondly, the irregular hole layout and vapor-liquid separation are optimized.

[0048] The flow equalization and guiding section is located in the area of ​​1 / 3 of the total height of the upper section of the guide shroud. Its sidewalls are inclined at a small angle of 6° to 8° with the vertical direction, which is the core area for opening in this embodiment.

[0049] Differentiated perforation structures and array arrangements are adopted on the four inclined surfaces of this section to balance flow capacity, airflow uniformity and structural strength under the constraint of 40% perforation rate. The perforation positions follow the principle of denser at the bottom and sparser at the top, matrix / cloverleaf array, and avoidance of the main path of liquid film on the edge. The lower part has a slightly higher perforation density or slightly larger perforation diameter to compensate for vapor pressure loss, and the upper part is appropriately sparse to ensure uniform airflow coverage throughout the entire area. All perforation axes are arranged perpendicular to the inclined surface with an inclination angle of 6° to 8°, and the perforation diameter is not less than 3mm to avoid clogging and the influence of surface tension.

[0050] While ensuring processability and flow stability, this embodiment provides a circular reference hole plus three innovative irregular hole designs to achieve efficient flow guidance, vapor-liquid separation, and condensate backflow prevention: Option 1: Standard circular pressure equalization hole (easiest to machine, stable flow) like Figure 5As shown, an array of circular through-holes with a uniform diameter of 3mm are opened on the four inclined surfaces of the flow equalization section. These holes are arranged in a matrix or quincunx pattern with equal spacing, slightly denser at the bottom and slightly sparser at the top. The hole diameter is appropriately reduced or the liquid film flow path is avoided in the edge areas. The total area of ​​the openings is controlled to be 40% of the surface area of ​​the opening region. Steam is uniformly sprayed outwards along the normal direction of the inclined surface, while condensate flows downwards along the inclined surface, with the flow direction nearly perpendicular to the steam spray direction (hole axis). Combined with the continuous jet of air inside the holes forming a gas barrier, this significantly reduces the risk of liquid backflow and achieves stable vapor-liquid separation.

[0051] Option 2: Vertical elongated oval guide hole (enhances flow guidance and suppresses backflow) like Figure 6 As shown, a vertically oriented elongated oval orifice is used, with the major axis arranged vertically and the minor axis horizontal, resulting in an equivalent flow diameter ≥3mm and an opening ratio of 40%. The elongated orifices are vertically positioned along the normal direction of the inclined plane, arranged in a denser array at the bottom and sparser array at the top. The vertical major axis structure conforms to the downward flow trend of the condensate, reducing the liquid film covering the orifice, while ensuring stable steam injection along the normal direction, further reducing the probability of backflow. This vertical major axis structure also helps guide the airflow to a uniform distribution in the vertical direction, improving the overall airflow uniformity.

[0052] Option 3: Teardrop-shaped anti-irrigation hole, wider at the top and narrower at the bottom. like Figure 7 As shown, a teardrop-shaped orifice, wider at the top and narrower at the bottom, is used. The orifice opening is wider at the top and narrower at the bottom, with an overall vertical orientation and a minimum flow dimension ≥3mm. These orifices are arranged in an array with a 40% opening ratio, and the orifice axis is perpendicular to the inclined plane. The teardrop shape utilizes gravity and the gradual change in orifice shape to allow falling condensate to slide more easily along the orifice edge without entering the channel; steam still flows smoothly out along the normal direction, forming a stronger gas barrier. This structurally and actively prevents liquid backflow, greatly alleviating the problems of vapor-liquid mixing and poor reflux.

[0053] The aforementioned perforation schemes are all strictly arranged in the upper section of the flow-equalizing guide section with a small inclination angle of 6° to 8°, striving to achieve the best balance between flow resistance, airflow uniformity, and structural strength at a 40% perforation rate. Combined with the design principles of denser perforation at the bottom and sparser perforation at the top, avoiding edge liquid films, and perpendicular perforation axis to the inclined plane, the steam diffuses smoothly and evenly under uniform pressure, covering the entire evaporation section, thereby enhancing heat exchange uniformity and efficiency. The condensate flows smoothly back along the inclined plane, decoupling from the steam injection direction, and together with the irregular perforation structure, achieves efficient vapor-liquid separation, thus potentially overcoming the industry pain points of traditional guide components such as vapor-liquid mixing, liquid backflow, and obstructed backflow.

[0054] There are 4 passive steam baffles (17) in total, which are evenly arranged around the lower inlet of the baffle (16) with an angle of 90° between adjacent baffles. The baffles are made of elastic stainless steel sheet material with a thickness of 0.1 to 0.3 mm, preferably 0.2 mm. The overhang length of a single baffle is 8 to 15 mm and the width is 5 to 10 mm. The baffles are vibrated by the rising steam flow, which destroys the laminar boundary layer without the need for external power and control.

[0055] Specifically, four passive steam turbulence plates are evenly arranged at the lower inlet of the flow guide shroud. Under the action of rising steam flow, they generate high-frequency elastic vibration, which disrupts the laminar boundary layer in the gas phase region, enhances the steam disturbance and the uniform distribution effect across the entire area, eliminates the hidden dangers of local airflow eddies and deflection, and achieves pure passive flow uniformity optimization without the need for external power and electronic control components.

[0056] The liquid level sensor (18) is fixedly installed in the liquid phase zone (2) of the immersion chamber at a preset position, away from steam turbulence and high-temperature heat exchange area, to avoid interference with the monitoring signal; the liquid level sensor (18) adopts a static pressure type or float type sensing structure, the working voltage is adapted to the conventional power supply specifications of the system, and has real-time liquid level acquisition and signal transmission functions. It can continuously monitor the liquid level height of the coolant in the immersion chamber, accurately reflect the liquid level fluctuation status, facilitate timely investigation of abnormal working conditions such as coolant leakage and low liquid level, and ensure the continuous and stable operation of the immersion phase change heat dissipation system; the sensor installation height can be adaptively adjusted for different sized chambers, and the monitoring accuracy is not less than ±1mm, which meets the liquid level control requirements of the system.

[0057] The controller (12), temperature sensor (11), and speed sensor (7) constitute the control component. The temperature sensor (11) is arranged in the liquid phase zone, gas phase zone, inside the heat sink (13), and in the external environment to collect temperature data at each point in real time. The speed sensor (7) is installed on the cooling fan to monitor the fan speed in real time. The controller (12) is electrically connected to the temperature sensor (11), speed sensor (7), and cooling fan. Based on the temperature monitoring data, the speed of the cooling fan is automatically adjusted.

[0058] The controller uses an edge PLC controller with a built-in PID algorithm to perform load-adaptive and precise control of the cooling fan, and clearly defines the temperature control threshold: when the server is under high load conditions with the liquid phase temperature of the immersion cooling box at 45-55℃, the cooling fan speed is automatically increased to improve the heat dissipation efficiency of the pulsating heat pipe condensation section and adapt to the high load condensation requirements; when the server is under low load conditions with the liquid phase temperature at 35-40℃, the cooling fan speed is automatically decreased to reduce system energy consumption and avoid excessive condensation in the pulsating heat pipe evaporation section.

[0059] Example 2 One embodiment of the present invention provides an immersion phase change heat dissipation method based on partition adaptation, comprising: Step S1: The heat generated by the operation of the heating element to be cooled is transferred to the low-boiling-point insulating cooling medium in the liquid phase region. After the cooling medium absorbs heat and boils, it generates steam, which rises into the gas phase region. Step S2: Steam enters the interior of the guide shroud through the lower inlet, flows upward along the guide shroud, and is evenly sprayed onto the surface of the evaporation section of the pulsating heat pipe through the steam outlet holes on the upper side wall. Step S3: Steam condenses and releases heat on the surface of the evaporation section. The released condensation heat is transferred to the working fluid inside the pulsating heat pipe. After the internal working fluid absorbs heat, it forms a two-phase pulsating cycle of vapor and liquid, which transfers heat to the condensation section and dissipates it to the outside. Step S4: The cooling fluid droplets formed by condensation naturally flow back to the liquid phase region along the outer wall of the guide shroud and the outer wall of the evaporation section of the pulsating heat pipe, completing the circulation of the cooling fluid.

[0060] Using the server as the heat-generating element to be cooled and fluorinated liquid as a low-boiling-point insulating cooling medium, a specific implementation step is provided: 1. Heating and boiling: The heat generated by the operation of the server (1) is transferred to the fluorinated liquid in the liquid phase region (2). After the fluorinated liquid reaches the boiling point, it boils and generates a large amount of fluorinated liquid vapor, which enters the gas phase region (5) upward.

[0061] 2. Steam diversion: The steam is collected by the flow guide shroud (16) and directed to the surface of the evaporation section (6) of the pulsating heat pipe array (10) via the flow equalization guide section.

[0062] During the flow guiding process, the disturbance component (17) breaks the steam laminar flow and generates elastic vibration under the action of the rising steam flow, which equalizes and disturbs the steam, so that the airflow enters the flow guide shroud (16) evenly.

[0063] 3. High-efficiency condensation: Steam rapidly condenses into discrete droplets on the hydrophobic microstructure surface of the heat pipe evaporation section (6), and the released condensation heat is absorbed by the mixed working fluid inside the heat pipe.

[0064] 4. Heat transfer: After absorbing heat, the working fluid inside the heat pipe evaporates, forming a vapor column that moves upward to the condensation section (8). Under the action of the fins (9) and the fan (14), it releases heat and condenses into a liquid state.

[0065] 5. Working fluid reflux: After condensation, the heat pipe working fluid flows downward back to the evaporation section (6) under the action of gravity and capillary force, completing the self-pulsating circulation inside the heat pipe.

[0066] 6. Fluoride solution reflux: The fluorinated liquid condensate droplets on the surface of the heat pipe fall off, pass through the outer wall of the guide shroud (16), and quickly flow back to the liquid phase area (2) of the immersion tank, re-wrap the server (1), and complete the cyclic cooling of the fluorinated liquid.

[0067] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An immersion phase change heat dissipation device based on partition adaptation, characterized in that, include: The immersion cooling chamber is a sealed pressure-bearing shell. Its interior is divided into a gas phase zone and a liquid phase zone from top to bottom. The liquid phase zone is where the heating elements to be cooled are arranged and filled with a low-boiling-point insulating cooling medium. The pulsating heat pipe array consists of multiple closed-loop pulsating heat pipes, each arranged vertically, and from top to bottom, it consists of a condensation section, an adiabatic section, and an evaporation section; wherein, the evaporation section is located within the gas phase region, and the condensation section and the adiabatic section extend to the outside of the housing. The flow guide shroud is located in the gas phase zone between the evaporation section and the cooling working fluid liquid surface. It has a flared, two-section truncated quadrangular truncated structure. Its lower end opening serves as a steam inlet and is positioned opposite to the cooling working fluid liquid surface in the liquid phase zone to collect rising steam. The steam outlet holes on its upper sidewall are arranged facing the evaporation section of the pulsating heat pipe to uniformly guide the steam to the surface of the evaporation section.

2. The immersion phase change heat dissipation device based on partition adaptation as described in claim 1, characterized in that, The pulsating heat pipe array is arranged in a centrally symmetrical manner, and has a square configuration when viewed from above, forming a spatial fit with the flow guide shroud; wherein, the pulsating heat pipes that are directly contacted by the steam jet ejected from the steam outlet of the flow guide shroud have their evaporation sections inclined towards the flow guide shroud at a preset angle to the vertical direction, while the pulsating heat pipes on the outside that are not directly covered by the steam jet remain vertically arranged.

3. The immersion phase change heat dissipation device based on partition adaptation according to claim 1, characterized in that, The outer wall of the condensation section of the pulsating heat pipe is provided with a corrugated fin structure. A heat dissipation shroud is provided on the outside of the box corresponding to the condensation section. The heat dissipation shroud forms a closed heat dissipation cavity. Air inlets and outlets are symmetrically opened on both sides of the box. Cooling fans are symmetrically arranged at the air inlets to form a bidirectional cross-flow cooling field.

4. The immersion phase change heat dissipation device based on partition adaptation according to claim 1, characterized in that, The cooling fan is electrically connected to the controller, which adaptively adjusts the cooling fan speed based on real-time data collected by the temperature sensor of the cavity temperature, condenser end temperature, and ambient temperature.

5. The immersion phase change heat dissipation device based on partition adaptation as described in claim 1, characterized in that, The outer wall of the evaporation section of the pulsating heat pipe is provided with a three-layer composite enhanced condensation structure, which consists of a high thermal conductivity copper foil base layer, a gradient capillary microstructure layer, and a superhydrophobic modification layer from the inside out. The gradient capillary microstructure layer is a nanoscale radial and axial groove array, and the superhydrophobic modification layer is a micro-nano hierarchical rough structure prepared by femtosecond laser processing, with a microcapsule self-healing fluorosilane coating on its surface.

6. The immersion phase change heat dissipation device based on partition adaptation as described in claim 1, characterized in that, The flow guide is divided into a closed flow guide section and a flow equalization flow guide section from bottom to top, and the whole is in the shape of a truncated quadrangular truncated pyramid. The side wall of the closed flow guide section is inclined at a preset angle to the vertical direction and is a solid inclined surface structure without through holes. The side wall of the flow equalization flow guide section is inclined at a preset angle to the vertical direction, and the upper and lower conical surfaces are smoothly transitioned by a circular arc.

7. The immersion phase change heat dissipation device based on partition adaptation as described in claim 1, characterized in that, Steam outlet holes are provided on the four inclined surfaces of the flow equalization and guiding section. The hole positions follow the principle of denser arrangement at the bottom and sparser arrangement at the top, matrix or plum blossom array, and avoidance of the main path of the liquid film at the edge. All hole axes are arranged perpendicular to the inclined surface. The steam outlet holes are one or more combinations of circular through holes, vertically elongated oval holes, or teardrop-shaped holes that are wider at the top and narrower at the bottom.

8. The immersion phase change heat dissipation device based on partition adaptation as described in claim 1, characterized in that, Several passive steam turbulence plates are evenly arranged around the lower inlet of the flow guide shroud. Adjacent turbulence plates are arranged vertically. The upward flow of steam drives the turbulence plates to vibrate, thereby equalizing and disturbing the steam flow and ensuring that the airflow enters the flow guide shroud evenly.

9. The immersion phase change heat dissipation device based on partition adaptation as described in claim 1, characterized in that, The inner wall of the gas phase zone is provided with a flow guiding angle and is covered with a heat insulation layer; in the area corresponding to the evaporation section of the pulsating heat pipe, the heat insulation layer is provided with a local clearance opening, the size of which is larger than the outer diameter of the pulsating heat pipe.

10. An immersion phase change heat dissipation method based on partition adaptation, characterized in that, The immersion phase change heat dissipation device according to any one of claims 1-9 includes: The heat generated by the cooling heating element is transferred to the low-boiling-point insulating cooling medium in the liquid phase region. After the cooling medium absorbs heat and boils, it generates steam, which then rises into the gas phase region. Steam enters the interior of the guide shroud through the lower inlet, flows upward along the guide shroud, and is evenly sprayed onto the surface of the evaporation section of the pulsating heat pipe through the steam outlet holes on the upper side wall. Steam condenses and releases heat on the surface of the evaporation section. The released condensation heat is transferred to the working fluid inside the pulsating heat pipe. After the working fluid absorbs heat, it forms a two-phase pulsating cycle of vapor and liquid, which transfers heat to the condensation section and dissipates it to the outside. The cooling fluid droplets formed by condensation naturally flow back to the liquid phase region along the outer wall of the guide shroud and the outer wall of the evaporation section of the pulsating heat pipe, completing the circulation of the cooling fluid.

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