A phase change heat transfer device

Abstract

The application relates to the technical field of phase change heat transfer, and discloses a phase change heat transfer device, which actively drives liquid working medium backflow by additionally arranging a pump driving system, effectively breaks through the bottleneck of the prior art, the mechanical driving force provided by the pump driving is far greater than capillary pressure, and is not restricted by the relationship that porosity and permeability are consumed by each other, the circulating flow of the working medium can be significantly increased, the heat dissipation demand of a high-power electronic device is met, the backflow of the pump driving and the steam flow path are independent of each other, the reverse hindering of high-pressure steam in the evaporation area to the liquid working medium backflow is avoided, the dry-out failure risk is eliminated, and the operation reliability under a high heat flux density condition is improved, the wicking core not only reduces steam escape resistance and strengthens evaporation heat exchange, but also makes it possible that the whole device develops in the direction of ultrathin, so that the heat dissipation performance and structural compactness are synergistically improved.

Description

Technical Field

[0001] This application relates to the field of phase change heat transfer technology, and more particularly to a phase change heat transfer device. Background Technology

[0002] As electronic devices evolve towards higher frequencies, higher speeds, and higher integration, their functions become increasingly complex, resulting in greater heat dissipation power per unit volume and higher heat flux density. Prolonged operation at high temperatures inevitably leads to decreased reliability, reduced lifespan, and even functional failure of electronic devices. Currently, phase change heat transfer devices are one of the most effective technologies for heat dissipation in high-power electronic devices (i.e., heat sources).

[0003] In existing technologies, traditional phase change heat transfer devices typically consist of a shell with an internal cavity, a liquid wick (such as porous media like sintered powder, sintered wire mesh, or foamed metal), and a phase change working fluid (such as water or ethanol). As a heat transfer device, it enables efficient long-distance heat transfer and rapid diffusion of concentrated heat flow. Its working principle is as follows: Heat from the high-temperature region enters the phase change heat transfer device, causing the liquid working fluid in the wick to evaporate and undergo a phase change, forming vapor. Under the influence of pressure difference, the vapor flows to the low-temperature region (such as the contact point between the phase change heat transfer device and a liquid-cooled plate or air-cooled radiator), where it condenses and undergoes a phase change, releasing heat. After condensation, the liquid working fluid flows back to the high-temperature region under the capillary action of the wick, thus completing the cycle.

[0004] However, traditional phase change heat transfer devices rely solely on capillary action provided by the wick to drive the flow of the working fluid, resulting in the following technical bottlenecks: First, there is an inherent contradiction between capillary driving force and flow resistance: the capillary pressure provided by the wick is limited, and the internal flow resistance is relatively large, resulting in a small working fluid circulation flow rate, which is insufficient to meet the heat dissipation requirements of high-power electronic devices. More fundamentally, there is an inverse relationship between capillary pressure and permeability: a wick with smaller pores can generate a larger capillary driving force, but the permeability decreases accordingly, which is not conducive to the efficient reflux of the liquid working fluid. This contradiction makes it difficult to balance the performance of the wick, thus restricting further improvements in the heat dissipation capacity of phase change heat transfer devices.

[0005] Second, there is mutual interference between vapor flow and working fluid reflux: the wick serves the dual function of providing evaporation nucleation sites and constructing liquid phase reflux channels. When a high heat flux density is input, the vapor pressure in the evaporation zone increases significantly, which creates a large reverse resistance to the flow of liquid working fluid inside the wick, hindering the circulation of the working fluid, and in severe cases, even causing the device to fail due to drying out.

[0006] Therefore, improvements to existing technologies are necessary. Summary of the Invention

[0007] This application provides a phase change heat transfer device to solve the problems existing in the prior art.

[0008] To achieve the above objectives, this application provides the following technical solution: A housing having an inner cavity, the inner cavity including an evaporation zone and a condensation zone; the evaporation zone is located at one end of the housing, the condensation zone is located at the other end of the housing, and the one end and the other end of the housing are the two ends of the housing along its length. A liquid-absorbing core is disposed within the inner cavity, and the liquid-absorbing core is spaced apart from the top of the housing; The phase change working fluid, filled in the inner cavity, can release heat and condense into a liquid in the condensation zone, and then flow from the condensation zone to the evaporation zone under the capillary action of the liquid suction core; and can also absorb heat and evaporate into a gas in the evaporation zone, and then flow from the evaporation zone to the condensation zone under the action of the gas pressure difference. A pump-driven system is used to drive the liquid phase change working fluid to flow from the condensation zone to the evaporation zone.

[0009] Furthermore, the pump drive system includes a piezoelectric pump, which has a liquid intake port and a liquid discharge port. The liquid intake port is connected to the condensation zone, and the liquid discharge port is connected to the evaporation zone. The piezoelectric pump is used to drive the flow of the liquid phase change working fluid. The piezoelectric pump is disposed inside the inner cavity; or, the piezoelectric pump is disposed on the side of the housing opposite to the inner cavity, and the housing has a first communication port and a second communication port; the liquid extraction port is connected to the condensation zone via the first communication port, and the liquid discharge port is connected to the evaporation zone via the second communication port.

[0010] Furthermore, the pump drive system also includes a flow guide seat and a flow guide pipe; The flow guide seat is disposed in the inner cavity and located in the condensation zone. The flow guide seat has a first liquid inlet, a first liquid outlet, a second liquid inlet, and a second liquid outlet, which are used to guide the flow direction of the liquid phase change working fluid. The first liquid inlet is connected to the first liquid outlet, and the second liquid inlet is connected to the second liquid outlet. The piezoelectric pump is connected to the flow guide seat, the liquid extraction port is connected to the first liquid outlet, and the liquid discharge port is connected to the second liquid inlet; The guide tube has an inlet end and an outlet end, which are used to cooperate with the guide seat to guide the liquid phase change working fluid to the evaporation zone; the inlet end is connected to the second liquid outlet, and the outlet end extends to the evaporation zone.

[0011] Furthermore, the guide tube is positioned above the liquid-absorbing core; or, The guide tube is disposed inside the liquid-absorbing core.

[0012] Furthermore, a groove is provided at the bottom of the flow guide seat, and the groove and the inner side of the bottom of the shell form a liquid collection chamber; The first liquid inlet is located at the bottom of the groove.

[0013] Furthermore, the bottom of the housing has a bent structure, which includes a first wall, a second wall, and a third wall. The first distance is less than the second distance. The first distance is the distance between the first wall and the top of the housing, and the second distance is the distance between the second wall and the top of the housing. The first wall and the second wall are connected by the third wall. The groove is disposed opposite to the second wall to form a liquid-gathering chamber.

[0014] Furthermore, the phase change heat transfer device also includes a control module; The control module is electrically connected to the piezoelectric pump and is used to control the start and stop of the piezoelectric pump and / or adjust the operating parameters of the piezoelectric pump. The control module includes a manual control unit, which can be manually operated to control the start and stop of the piezoelectric pump and / or adjust the operating parameters of the piezoelectric pump.

[0015] Alternatively, the control module may include an automatic control unit and a temperature sensor; The automatic control unit is connected to the temperature sensor and is used to automatically control the start and stop of the piezoelectric pump and / or adjust the operating parameters of the piezoelectric pump according to the temperature parameters of the heat source collected by the temperature sensor. Alternatively, the control module may include an automatic control unit and a power detector; The automatic control unit is connected to the power detector and is used to automatically control the start and stop of the piezoelectric pump and / or adjust the operating parameters of the piezoelectric pump according to the power parameters of the heat source collected by the power detector. Alternatively, the control module may include an automatic control unit and a water level detector; The water level detector is located at the bottom of the groove and is used to send a start signal after detecting that the liquid phase change working fluid accumulated in the liquid accumulation chamber has reached a specified water level. The automatic control unit is connected to the water level detector and is used to automatically control the start and stop of the piezoelectric pump and / or adjust the operating parameters of the piezoelectric pump after receiving the start signal.

[0016] Furthermore, the inner wall of the housing located in the condensation zone is provided with a hydrophobic surface layer.

[0017] Furthermore, the pump-driven system also includes a partition; the partition is located within the inner cavity, and the partition includes a first side and a second side, the first side being the side facing the condensation zone, and the second side being the side facing away from the condensation zone; the piezoelectric pump is used to drive the liquid phase change working fluid from the condensation zone to the target cavity, the target cavity being constructed based on the second side, and the target cavity being in communication with the evaporation zone.

[0018] Compared with the prior art, this application has the following beneficial effects: This application provides a phase change heat transfer device in which the liquid wick is spaced apart from the top of the shell, thus creating a certain space (referred to as the target space for ease of description). The vaporized phase change working fluid can flow from the evaporation zone to the condensation zone through this target space without the need for a physical evaporation pipe (a physical evaporation pipe refers to a physical pipe used to transfer the vaporized phase change working fluid from the evaporation zone to the condensation zone). This not only simplifies the device structure but also improves the flow efficiency of the vaporized phase change working fluid from the evaporation zone to the condensation zone, thereby achieving cost reduction and efficiency improvement. Furthermore, since the phase change heat transfer device in this application includes a pump-driven system that actively drives the liquid phase change working fluid to flow from the condensation zone to the evaporation zone, it effectively solves the multiple technical bottlenecks faced by the prior art that rely solely on capillary action to drive the working fluid circulation: First, the driving force provided by the pump-driven system is much greater than the capillary pressure of the wick and is not constrained by the inverse relationship between porosity and permeability, which can significantly increase the working fluid circulation flow rate and meet the heat dissipation requirements of high-power electronic devices; Second, this phase change heat transfer device can effectively reduce or even avoid the reverse obstruction of the high-pressure steam in the evaporation zone to the backflow of the liquid working fluid, eliminate the risk of drying failure, and improve the operational reliability of the device under high heat flux density conditions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is one of the structural schematic diagrams of a phase change heat transfer device provided in the embodiments of this application; Figure 2 This is a second schematic diagram of the structure of a phase change heat transfer device provided in the embodiments of this application; Figure 3 This is a three-dimensional structural schematic diagram of the pump-driven system provided in the embodiments of this application; Figure 4This is a schematic diagram (cross-sectional view) of the structure of the pump-driven system provided in the embodiments of this application; Figure 5 This is a three-dimensional structural diagram of the pump drive system and suction core provided in the embodiments of this application; Figure 6 This is the third schematic diagram of the structure of a phase change heat transfer device provided in the embodiments of this application; Figure 7 This is the fourth schematic diagram of a phase change heat transfer device provided in the embodiments of this application; Figure 8 This is a schematic diagram of a separator from one perspective provided in an embodiment of this application.

[0021] Figure label: 1-Shell; 2-Inner cavity; 3-Liquid suction core; 4-Phase change working medium; 5-Pump drive system; 501-Piezoelectric pump; 502-Flow guide seat; 503-Flow guide tube; 504-First liquid inlet; 505-First liquid outlet; 506-Second liquid inlet; 507-Second liquid outlet; 508-Liquid extraction port; 509-Liquid discharge port; 510-Inlet end; 511-Outlet end; 512-Groove; 513-Liquid collection chamber; 104-Separator; 1041-First side; 1042-Second side; 101-First wall; 102-Second wall; 103-Third wall; 105-Bottom of the shell. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] Please refer to Figures 1-2 This application provides a phase change heat transfer device that breaks through the inherent performance bottleneck of the prior art, which relies solely on capillary force to drive the circulation of the working fluid.

[0027] The phase change heat transfer device includes a housing 1, a liquid wick 3, a phase change working fluid 4, and a pump-driven system 5. It has an inner cavity 2, which includes an evaporation zone and a condensation zone. The evaporation zone is located at one end of the housing 1, and the condensation zone is located at the other end of the housing 1. The one end and the other end of the housing 1 are the two ends of the housing 1 along its length. The liquid wick 3 is disposed within the inner cavity 2, spaced apart from the top of the housing 1. The phase change working fluid 4 fills the inner cavity 2 and can release heat and condense into a liquid state in the condensation zone, flowing from the condensation zone to the evaporation zone under the capillary action of the liquid wick 3. It can also absorb heat and evaporate into a vapor state in the evaporation zone, flowing from the evaporation zone to the condensation zone under the action of a pressure difference. The pump-driven system 5 drives the liquid phase change working fluid 4 to flow from the condensation zone to the evaporation zone.

[0028] The length direction refers to the length direction of the shell.

[0029] As an example, and not a limitation, the phase change heat transfer device includes a housing 1, which is made of a thermally conductive material, such as aluminum, copper, aluminum alloy, or copper alloy, and is manufactured through integral welding or integrated molding processes. The housing 1 encloses a sealed inner cavity 2. The inner cavity 2 is divided along the length of the housing 1 into two functionally distinct regions: an evaporation zone located near the external heat source and a condensation zone located away from the heat source. The condensation zone can at least partially be fitted and installed with an external heat sink (such as a liquid-cooled plate or an air-cooled heat sink). In terms of spatial layout, the evaporation zone is fixedly located at one end of the housing 1 (e.g., [missing information - likely a specific location]). Figures 1-2 (As shown on the left end), the condensation zone is correspondingly located at the other end of the housing 1 (e.g., the left end). Figures 1-2 (As shown on the right end), the inner cavity 2 provides flow space for the liquid and gaseous flow of the phase change working fluid 4. The length direction of the shell can be aligned with the length direction of the phase change heat transfer device.

[0030] As an example, and not a limitation, the inner cavity 2 is fixedly provided with a liquid-absorbing core 3. One side of the liquid-absorbing core 3 is spaced apart from the top of the shell 1. For example, the distance between one side of the liquid-absorbing core 3 and the top of the shell 1 is greater than 0.1 mm, such as greater than 0.4 mm and less than 0.6 mm. The other side of the liquid-absorbing core 3 is connected to the bottom of the shell 1. A target space is formed between one side of the liquid-absorbing core 3 and the top of the shell 1, through which the gaseous phase change working fluid can flow from the evaporation zone to the condensation zone. The liquid-absorbing core 3 covers the entire inner wall surface of the evaporation zone, or it can cover part of the inner wall surface of the evaporation zone, or it can extend to cover part of the inner wall area of ​​the condensation zone according to the actual heat transfer requirements. The liquid-absorbing core 3 can be used as the core enhanced heat exchange structure of the evaporation end. The term "inner wall" in this document can refer to the wall / side / surface that surrounds and forms the inner cavity 2, that is, the wall / side / surface facing the inner cavity 2. In addition, the liquid-absorbing core 3 can be disposed on at least part of the bottom inner surface of the housing 1, wherein the bottom inner surface is the inner wall of the bottom (region) of the housing 1.

[0031] As an example, and not a limitation, the inner cavity 2 is filled with a specified amount of phase change working fluid 4. This phase change working fluid 4 can be adapted to the target operating temperature range of the device, using deionized water, anhydrous ethanol, fluorocarbons, or other low-boiling-point organic working fluids. The phase change working fluid 4 can release heat and condense into a liquid state in the low-temperature environment of the condensation zone. The condensed liquid phase change working fluid 4 can flow from the condensation zone to the evaporation zone under the capillary action of the wick 3 (the flow direction of the liquid phase change working fluid 4 may include, for example,...). Figures 1-2 The direction indicated by the blue arrow at the liquid suction core 3 (pointing from the right end to the left end of the shell) is as follows: The liquid phase change working fluid 4, transported to the evaporation zone, absorbs heat from the external heat source and undergoes evaporation and phase change to generate a gaseous phase change working fluid 4. Driven by the pressure difference between the evaporation zone and the condensation zone, the generated gaseous phase change working fluid 4 flows from the evaporation zone to the condensation zone (the flow direction of the gaseous phase change working fluid 4 may include...). Figures 1-2 All the directions indicated by the red arrows in the inner cavity 2 include: the direction from the bottom of the shell to the top of the shell, and the direction from the left end of the shell to the right end of the shell, thereby completing the phase change heat transfer cycle process.

[0032] As a core improvement and innovation of this application embodiment, the phase change heat transfer device is also equipped with a pump drive system 5. The pump drive system 5 is disposed in the housing 1 and can continuously output controllable mechanical driving force in the power-on operation state to actively drive the liquid phase change working fluid 4 collected in the condensation zone to flow from the condensation zone to the evaporation zone.

[0033] The pump-driven system of this application can drive the liquid phase change working fluid to flow along the length of the shell. The driving force of the pump-driven system is used less to overcome the gravity of the liquid phase change working fluid, thereby improving the transfer efficiency of the pump-driven system for the liquid phase change working fluid.

[0034] This application provides a phase change heat transfer device in which a target space is formed between the liquid wick and the top of the shell due to the spaced arrangement of the liquid wick and the top of the shell. The gaseous phase change working fluid can flow from the evaporation zone to the condensation zone through this target space without the need for a physical evaporation pipe. This not only simplifies the device structure but also improves the flow efficiency of the gaseous phase change working fluid from the evaporation zone to the condensation zone, thereby achieving cost reduction and efficiency improvement. Furthermore, since the phase change heat transfer device in this application includes a pump-driven system that actively drives the liquid phase change working fluid to flow from the condensation zone to the evaporation zone, it effectively solves the multiple technical bottlenecks faced by the prior art that rely solely on capillary action to drive the working fluid circulation: First, the driving force provided by the pump-driven system is much greater than the capillary pressure of the wick, and is not constrained by the inverse relationship between porosity and permeability, which can significantly increase the working fluid circulation flow rate and meet the heat dissipation requirements of high-power electronic devices; Second, this phase change heat transfer device can effectively reduce or even avoid the reverse obstruction of the high-pressure steam in the evaporation zone to the backflow of the liquid working fluid, eliminate the risk of drying failure, and improve the operational reliability of the device under high heat flux density conditions.

[0035] The technical solution disclosed in this application forms a pump-driven system 5 with an actively driven reflux path, solving the multiple technical bottlenecks that have long been faced by the prior art in relying solely on capillary action to drive the working fluid circulation: First, the mechanical driving force provided by the pump-driven system 5 is much greater than the maximum capillary pressure generated by the conventional wicking core 3, and the magnitude of this mechanical driving force can be dynamically adjusted according to the actual heat dissipation requirements of the device, completely unaffected by the inherent constraint of the inverse relationship between capillary pressure and permeability in the traditional wicking core 3 structure. This can significantly increase the overall circulation flow rate of the phase change working fluid 4 without sacrificing the heat exchange performance at the evaporation end, thereby increasing the ultimate heat transfer capacity of the device several times over, fully meeting the ever-increasing high heat flux density heat dissipation requirements of current high-power electronic devices; Second, the liquid working fluid reflux path constructed by the pump-driven system 5 can achieve a certain degree of physical isolation from the gaseous working fluid flow path inside the inner cavity 2, and the two are spatially independent and do not interfere with each other. This effectively avoids the reverse resistance force of high-pressure steam generated in the evaporation zone on the reflux process of liquid working fluid under high heat flux density conditions, completely eliminating the risk of local drying failure at the evaporation end that is prone to occur in traditional phase change heat transfer devices under ultra-high heat flux input, and greatly improving the reliability and service life of the device under long-term continuous operation under extreme high heat flux density conditions. Thirdly, designers can completely optimize the structural parameters of the liquid absorber 3 for the evaporation enhancement target, and prepare it into a porous evaporation enhancement structure with an extremely thin thickness. This can not only significantly shorten the flow path of steam escaping from the liquid absorber to the steam chamber, significantly reduce the evaporation phase change resistance, and enhance the boiling heat transfer performance at the evaporation end, but also directly and significantly reduce the overall thickness of the phase change heat transfer device, making it possible for the device to develop towards millimeter or even sub-millimeter level ultra-thinness. Ultimately, it achieves a synergistic and simultaneous improvement in the ultimate heat dissipation performance and structural compactness of the device, perfectly adapting to the thermal management application requirements of the new generation of lightweight and thin high-power electronic devices.

[0036] Optionally, the pump drive system 5 may include a pump.

[0037] As an example, and not a limitation, the pump can be any of the following: an electromagnetic pump or a piezoelectric pump.

[0038] In some embodiments, please refer to Figure 4 The pump drive system 5 includes a piezoelectric pump 501, which has a liquid intake port 508 and a liquid discharge port 509. The liquid intake port 508 is connected to the condensation zone, and the liquid discharge port 509 is connected to the evaporation zone. The piezoelectric pump 501 is used to drive the flow of the liquid phase change working fluid 4. The piezoelectric pump 501 is disposed inside the inner cavity 2; or, the piezoelectric pump 501 is disposed on the side of the housing 1 away from the inner cavity 2, and the housing 1 has a first connecting port and a second connecting port; the liquid extraction port 508 is connected to the condensation zone through the first connecting port, and the liquid discharge port 509 is connected to the evaporation zone through the second connecting port.

[0039] The piezoelectric pump 501 is disposed on the side of the housing 1 away from the inner cavity 2, which means that the piezoelectric pump 501 is disposed outside the housing. For example, the piezoelectric pump 501 is disposed on the top of the housing 1 away from the inner cavity 2, or the piezoelectric pump 501 is disposed on the bottom of the housing 1 away from the inner cavity 2.

[0040] If the piezoelectric pump is located at the bottom of the housing on the side opposite to the inner cavity, the piezoelectric pump can be closer to the external heat sink with a lower temperature, which is beneficial for effective control of the operating temperature of the piezoelectric pump.

[0041] Because the pump drive system includes a piezoelectric pump, it is able to have a stronger driving force to drive the flow of the liquid phase change working fluid.

[0042] Optionally, the pump drive system 5 further includes a flow guide seat 502 and a flow guide pipe 503; the flow guide seat 502 is disposed in the inner cavity 2 and located in the condensation zone, and the flow guide seat 502 has a first liquid inlet 504, a first liquid outlet 505, a second liquid inlet 506, and a second liquid outlet 507, for guiding the flow direction of the liquid phase change working fluid 4; the first liquid inlet 504 is connected to the first liquid outlet 505, and the second liquid inlet 506 is connected to the second liquid outlet 507. The liquid inlet 507 is connected; the piezoelectric pump 501 is connected to the guide seat 502, the liquid extraction port 508 is connected to the first liquid outlet 505, and the liquid discharge port 509 is connected to the second liquid inlet 506; the guide pipe 503 has an inlet end 510 and an outlet end 511, which are used to cooperate with the guide seat 502 to guide the liquid phase change working fluid 4 to the evaporation zone; the inlet end 510 is connected to the second liquid outlet 507, and the outlet end 511 extends to the evaporation zone.

[0043] Please refer to this again. Figures 1-2 and in conjunction with references Figures 3-5 In one embodiment of this example, the pump drive system 5 adopts a miniaturized integrated architecture design. The system is mainly composed of three core functional components: a piezoelectric pump 501, a flow guide seat 502, and a flow guide tube 503. All components are made of metal or polymer materials that are chemically compatible with the phase change working fluid. The system can operate stably in a closed vacuum cavity environment for a long time without corrosion, precipitation, or working fluid contamination risks.

[0044] The flow guide seat 502 is manufactured using an integrated injection molding or precision machining process and is integrally positioned in the low-level area of ​​the condensation zone of the inner cavity 2. This position is precisely the storage area where the condensed liquid working fluid collects during the phase change cycle, minimizing the risk of cavitation in the pump-driven system. The flow guide seat 502 has four functional interfaces: a first liquid inlet 504 and a first liquid outlet 505 corresponding to the first set of flow channels, and a second liquid inlet 506 and a second liquid outlet 507 corresponding to the second set of flow channels. The first liquid inlet 504 is directly open towards the storage area of ​​the condensation zone, allowing unobstructed introduction of the condensed low-temperature liquid phase change working fluid 4 (the suction direction of the liquid phase change working fluid 4 is as follows). Figures 1-2 As indicated by the blue arrow at the middle guide seat 502 (pointing from the bottom to the top of the shell), the first liquid inlet 504 and the first liquid outlet 505 are connected through the first set of flow channels inside the guide seat; the second liquid inlet 506 serves as the input end of the liquid working medium and is connected to the second set of flow channels inside the guide seat 502, and is finally output to the outside through the second liquid outlet 507. The two sets of flow channels work together to achieve precise constraint and guidance on the flow direction of the liquid phase change working medium 4, avoiding adverse flow conditions such as local eddies and excessive pressure drop inside the flow channels.

[0045] The piezoelectric pump 501, serving as the power core of the pump drive system 5, employs a micro piezoelectric vibrator drive structure and is housed within the housing 1. The piezoelectric pump 501 has a suction port 508 for drawing in liquid working fluid and a discharge port 509 for discharging liquid working fluid. After assembly, the suction port 508 is sealed and connected to the first outlet port 505, and the discharge port 509 is fluidly connected to the second inlet port 506. This constructs a suction flow channel from the liquid storage area of ​​the condensation zone to the piezoelectric pump 501, and an output flow channel from the piezoelectric pump 501 to the interior of the guide seat 502. During operation, the piezoelectric pump 501 generates periodic volume changes within the pump chamber through the high-frequency reciprocating vibration of the piezoelectric vibrator, continuously providing a stable driving force for the liquid phase change working fluid 4.

[0046] Understandably, due to the limited overall thickness of the phase change heat transfer device, the inlet and outlet ports (i.e., the suction port 508 and the discharge port 509) of the piezoelectric pump 501 are usually located on the same surface (e.g., the bottom surface of the piezoelectric pump).

[0047] As an example, and not a limitation, the guide tube 503 is integrally drawn from a high thermal conductivity metal tube and is disposed within the inner cavity 2 along the length of the phase change heat transfer device. The guide tube 503 has an inlet end 510 for receiving the liquid working fluid and an outlet end 511 for guiding the liquid phase change working fluid 4 to the evaporation zone in conjunction with the guide seat 502 (the guiding direction of the liquid phase change working fluid 4 can be as follows). Figures 1-2As indicated by the blue arrow at the middle guide tube 503 (pointing from the right end of the shell to the left end of the shell), after assembly, the inlet end 510 and the second liquid outlet 507 of the guide seat 502 are sealed and connected, and the outlet end 511 extends axially to the core high heat flow area of ​​the evaporation zone.

[0048] In some embodiments, the outlet end 511 has a porous atomizing structure. This allows the liquid working fluid to be uniformly sprayed and dispersed onto the surface of the absorbent core in the evaporation zone, significantly improving the uniformity of the working fluid distribution and preventing localized insufficient liquid supply in the evaporation zone.

[0049] For example, the porous atomizing structure has multiple (micro)pores and is capable of atomizing liquid working fluid.

[0050] In summary, through the coordinated assembly of the three components, an active liquid phase flow path relatively independent of the steam flow path is constructed. The liquid working fluid collected from the condensation zone sequentially enters the suction port 508 of the piezoelectric pump 501 through the first inlet 504 and the first outlet 505, and then is output from the discharge port 509. It then flows sequentially through the second inlet 506 and the second outlet 507, and then enters the guide pipe 503. Finally, it is precisely delivered to the core area of ​​the evaporation zone through the outlet end 511 of the guide pipe 503. There are no redundant flow channel inflections or local dead zones throughout the entire process. It can achieve high flow rate and high stability working fluid circulation with extremely low operating power consumption, and is fully compatible with the long-term continuous heat dissipation requirements of high-power electronic devices.

[0051] In one embodiment of this example, the number of piezoelectric pumps 501 is at least one; when at least two piezoelectric pumps 501 are provided, the at least two piezoelectric pumps 501 are arranged in parallel or in series.

[0052] Understandably, multiple piezoelectric pumps can be flexibly arranged in parallel or series according to heat dissipation requirements. Parallel arrangement can increase the circulation flow rate, while series arrangement can increase the total output pressure, thereby adapting to heat dissipation scenarios with different power levels and structural sizes, further improving the applicability and design flexibility of the device.

[0053] In one embodiment of this example, two differentiated preferred implementation methods that can be independently implemented are further disclosed for the installation configuration of the piezoelectric pump 501, with each method adapting to different application scenario requirements.

[0054] In the first embodiment, the piezoelectric pump 501 is internally mounted. Specifically, the piezoelectric pump 501 adopts a fully integrated, internal layout, completely housed within the inner cavity 2 formed by the housing 1, and mounted on the flow guide seat 502, as shown below. Figure 1 As shown; This layout completely encloses the piezoelectric pump 501 within the inner cavity 2, eliminating the need for additional fluid communication holes in the wall of the housing 1. This helps to eliminate the risk of working fluid leakage. At the same time, the saturated vapor environment inside the inner cavity enables full-enclosed isothermal cooling of the piezoelectric pump, preventing local overheating during long-term high-frequency operation. This significantly improves the overall structural compactness and long-term operational reliability of the device, making it particularly suitable for scenarios with extremely high requirements for overall device sealing and vibration and shock resistance.

[0055] In the second embodiment, the piezoelectric pump 501 is externally mounted. Specifically, the piezoelectric pump 501 adopts a completely external, split-type layout, and is integrally mounted on the housing 1, as shown below. Figure 2 As shown.

[0056] To achieve fluid communication between the internal and external flow channels, the housing 1 has two fluid communication through holes that communicate with the interior of the inner cavity 2, including a first communication port and a second communication port. After assembly, the liquid extraction port 508 of the piezoelectric pump 501 can be sealed and connected to the first liquid outlet 505 of the guide seat 502 through the first communication port, and the liquid discharge port 509 of the piezoelectric pump 501 can be sealed and connected to the second liquid inlet 506 of the guide seat 502 through the second communication port.

[0057] This external layout has three core technological advantages: First, the piezoelectric pump 501, as a consumable component, can be disassembled, repaired, and replaced independently without damaging the internal environment of the phase change heat transfer device, significantly reducing the maintenance cost of the device; Second, the piezoelectric pump 501 does not occupy the effective internal volume of the inner cavity 2, which can maximize the flow cross-sectional area of ​​the vapor chamber, reduce the flow pressure drop of the gaseous working fluid, and at the same time help the device to further iterate towards ultra-thinness and miniaturization; Third, the live working parts of the piezoelectric pump 501 are completely exposed to the external atmospheric environment, which completely avoids the safety hazards such as insulation failure and leakage short circuit that may be caused by long-term contact of live parts with liquid working fluid in the built-in installation scheme, especially suitable for large-scale mass production application scenarios with stringent requirements for electrical safety, such as consumer electronics and data center servers.

[0058] Understandably, these two installation methods can be flexibly selected based on the actual application scenario, structural size constraints, and reliability requirements of the target product, and both can stably achieve the core function of actively driving the circulation of the working fluid.

[0059] In one embodiment of this example, two differentiated implementation methods adapted to different structural constraints are disclosed for the assembly relationship between the guide tube 503 and the liquid suction core 3. The two schemes correspond to different space utilization rates and heat exchange enhancement requirements.

[0060] In the first embodiment, the guide tube 503 is positioned above the liquid-absorbing core 3, such as... Figures 1-2 As shown; This assembly process eliminates the need for secondary machining of the liquid-absorbing core 3 body. Standard-specification commercial metal capillary tubes can be directly used as guide tubes to quickly assemble with the pre-prepared liquid-absorbing core 3, significantly reducing the overall processing difficulty and mass production cost. At the same time, the outer surface of the guide tube 503 is in direct contact with the saturated vapor inside the inner cavity 2. The latent heat of vapor condensation can be used to preheat the low-temperature liquid working fluid flowing inside the tube, effectively avoiding the problem of local heat exchange oscillation caused by excessively low liquid supply temperature at the evaporation end. This process is suitable for large-scale consumer electronics mass production scenarios with high processing yield requirements.

[0061] In the second embodiment, the guide tube 503 is disposed inside the liquid suction core 3.

[0062] As an example and not a limitation, a channel may be machined in the liquid-absorbing core 3 and the guide tube 503 may be embedded in the channel.

[0063] This assembly structure allows the guide tube 503 to be housed within the physical space of the wick 3, without additionally occupying the steam chamber flow space inside the inner cavity 2. Without increasing the overall thickness of the phase change heat transfer device, it maximizes the effective flow cross-sectional area of ​​the steam chamber, further reducing the flow pressure drop of the vaporized working fluid. Simultaneously, the micropores in the wall of the guide tube 503 in the embedded state can be selectively opened as needed. The liquid working fluid flowing inside the tube can directly and uniformly diffuse into the surrounding porous medium through the interface between the tube wall and the wick, completely eliminating the problem of insufficient liquid supply at the edge of the evaporation end that is common in traditional end-supply methods. This significantly improves the liquid working fluid wetting coverage of the entire wick surface, further enhancing the boiling heat transfer performance at the evaporation end from a structural perspective, perfectly meeting the application requirements of ultra-thin, high heat flux density phase change heat transfer devices.

[0064] Understandably, these two assembly methods can be flexibly selected based on the thickness constraints of the device, the heat flux density index, and the mass production process capability, and both can stably achieve the core function of transporting liquid working fluid to the evaporation zone.

[0065] Please refer to this again. Figures 1-5 In one embodiment of this example, the bottom of the flow guide seat 502 is provided with a groove 512, and the groove 512 and the bottom inner side of the housing 1 form a liquid collection chamber 513. The first liquid inlet 504 is located at the bottom of the groove 512.

[0066] The liquid-gathering chamber 513 can be located at the lowest point of the entire inner cavity 2. The condensed liquid phase change working fluid 4 can be collected and stored inside the chamber by gravity, eliminating the need for complex drainage structures. When the liquid level in the chamber reaches a level sufficient to fill it, the piezoelectric pump 501 can draw the working fluid through the guide seat 502 and guide it.

[0067] Optionally, the bottom of the housing 1 has a bent structure, the bent structure including a first wall 101, a second wall 102 and a third wall 103, a first distance less than a second distance, the first distance being the distance between the first wall 101 and the top of the housing 1, the second distance being the distance between the second wall 102 and the top of the housing 1, the first wall 101 and the second wall 102 being connected by the third wall; the groove 512 is disposed opposite to the second wall 102 to form a liquid-gathering chamber 513.

[0068] As an example, and not a limitation, please refer to Figure 6 The first wall and the second wall are both planar walls. The second wall 102 is located below the groove 512. The groove 512 and the second wall 102 cooperate to form a liquid collection chamber 513. The third wall 103 can be spaced apart from the flow guide seat.

[0069] In this embodiment, the formed liquid-gathering chamber is similar to a liquid storage tank structure, which can effectively increase the storage capacity of the guide seat for the surrounding liquid working fluid, thereby avoiding the problem of the pump failing to pump liquid normally. This design helps to reduce the risk of the pump running dry and improves the performance stability of the pump drive.

[0070] Optionally, the pump drive system 5 includes a piezoelectric pump 501 and a separator 104; the separator 104 is located in the inner cavity 2, and the separator 104 includes a first side 1041 and a second side 1042, the first side 1041 being the side facing the condensation zone, and the second side 1042 being the side facing away from the condensation zone; the piezoelectric pump 501 is used to drive the liquid phase change working fluid 4 from the condensation zone to the target cavity, the target cavity being constructed based on the second side 1042, and the target cavity being in communication with the evaporation zone.

[0071] In some embodiments, the target cavity is formed by a second side 1042, a top of the housing, and a bottom 105 of the housing.

[0072] As an example, and not a limitation, please refer to Figure 7 and Figure 8The piezoelectric pump 501 is located outside the housing, that is, the piezoelectric pump 501 is not located inside the cavity. The phase change heat transfer device does not need to be equipped with a flow guide seat and flow guide pipe. The partition 104 can be a U-shaped rib plate.

[0073] See also Figure 7 The liquid phase change working fluid can flow from the condensation zone to the target cavity under the drive of a piezoelectric pump (the flow direction of the liquid phase change working fluid may include, for example,...). Figure 7 The arrows in the condensation zone and the target cavity indicate different directions. The arrow in the condensation zone points from the bottom to the top of the shell, while the arrows in the target cavity point from the top to the bottom of the shell and from the right end to the left end of the shell. Since the target cavity is connected to the evaporation zone, the liquid phase change working fluid can flow through the target cavity to the evaporation zone. After absorbing heat from an external heat source, the liquid phase change working fluid evaporates and undergoes a phase change to generate a gaseous phase change working fluid. Driven by the pressure difference between the evaporation zone and the condensation zone, the generated gaseous phase change working fluid flows from the evaporation zone to the condensation zone (the flow direction of the gaseous phase change working fluid may include...). Figure 7 The direction indicated by the red arrow in the middle, Figure 7 The directions indicated by the red arrows include: the direction from the bottom of the shell to the top of the shell, and the direction from the left end of the shell to the right end of the shell.

[0074] In this embodiment, the structure of the phase change heat transfer device is simpler, which is conducive to the thinning of the phase change heat transfer device, that is, the thickness of the phase change heat transfer device can be reduced as much as possible without affecting the performance of the phase change heat transfer device.

[0075] In one embodiment of this invention, the inner wall of the housing 1 located in the condensation zone is provided with a hydrophobic surface layer.

[0076] As an example, and not a limitation, the hydrophobic surface layer can be formed on the inner wall surface of the condensation zone of the housing 1 by means of nano-coating, microstructure etching, or chemical vapor deposition, giving the inner wall surface superhydrophobic properties (contact angle generally greater than 150°). When steam enters the condensation zone and comes into contact with the inner wall, due to the presence of the hydrophobic surface layer, the steam cannot spread on the inner wall surface to form a continuous liquid film, but instead condenses into beads, forming several independent spherical or hemispherical liquid droplets on the inner wall surface.

[0077] Compared to film condensation, bead condensation avoids the thermal resistance of the liquid film covering the inner wall of the shell, allowing subsequent steam to continuously and directly contact the inner wall surface of the shell. This significantly reduces the heat transfer resistance during condensation, thereby significantly improving the overall heat transfer performance and condensation efficiency of the condensation zone. When the condensation efficiency of film condensation cannot meet the system's heat dissipation or condensation load requirements, the hydrophobic surface layer can be used to induce bead condensation of steam, effectively solving the problem of heat transfer deterioration caused by liquid film adhesion and optimizing condensation performance while maintaining structural compactness.

[0078] In one embodiment of this invention, the phase change heat transfer device further includes a control module; the control module is electrically connected to the piezoelectric pump 501 and is used to control the start and stop of the piezoelectric pump 501 and / or adjust the operating parameters of the piezoelectric pump 501.

[0079] On the one hand, the control module may include a manual control unit; the manual control unit can be manually operated by the operator according to the actual working conditions to directly control the start and stop of the piezoelectric pump 501 and / or adjust the working parameters of the piezoelectric pump 501 (such as driving voltage, vibration frequency, output flow, etc.), thereby realizing the manual control of the circulation rate of the phase change working medium 4, which is suitable for flexible intervention in the commissioning stage or under special working conditions.

[0080] On the other hand, the control module may include an automatic control unit and a temperature sensor; the temperature sensor is located near the heat source or in the evaporation zone to collect the temperature parameters of the heat source in real time; the automatic control unit is signal-connected to the temperature sensor and is used to automatically control the start and stop of the piezoelectric pump 501 and / or adjust the operating parameters of the piezoelectric pump 501 based on the temperature data fed back by the temperature sensor. When the heat source temperature rises to a preset threshold, the automatic control unit may automatically start the piezoelectric pump 501 or increase its output power to enhance the liquid supply capacity and suppress the temperature rise; when the temperature drops back to a safe range, the pump speed may be reduced or the pump may be stopped to achieve optimized management of heat dissipation and power consumption.

[0081] Alternatively, the control module may include an automatic control unit and a power detector; the power detector is used to monitor the power parameters of the heat source in real time; the automatic control unit is signal-connected to the power detector and is used to automatically control the start and stop of the piezoelectric pump 501 and / or adjust the operating parameters of the piezoelectric pump 501 based on the power data fed back by the power detector. Since the power of the heat source and the amount of heat generated are directly related, this control method can proactively predict changes in heat dissipation demand, adjust the working fluid circulation rate in advance, and improve the timeliness and stability of the system response.

[0082] Alternatively, the control module may include an automatic control unit and a water level detector. The water level detector is located at the bottom of the groove 512 and is used to monitor the liquid level of the liquid phase change working fluid 4 accumulated in the liquid collection chamber 513 in real time. Upon detecting that the liquid level has reached a specified level, it sends a start signal. The automatic control unit is signal-connected to the water level detector and is used to automatically control the start / stop of the piezoelectric pump 501 and / or adjust the operating parameters of the piezoelectric pump 501 upon receiving the start signal. This control method uses the liquid level in the condensation zone as a trigger condition, ensuring that the piezoelectric pump 501 starts when there is sufficient liquid working fluid, avoiding dry running. Simultaneously, it can dynamically adjust the pump speed according to changes in the liquid level, achieving adaptive matching between the liquid supply and the condensation rate, further improving the safety and energy efficiency of the device operation.

[0083] As an example, and not a limitation, the specified water level can be a preset water level value.

[0084] Although this application uses terms such as shell and cavity frequently, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this application; interpreting them as any additional limitation would contradict the spirit of this application.

[0085] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A phase change heat transfer device, characterized in that, include: The shell (1) has an inner cavity (2), the inner cavity (2) including an evaporation zone and a condensation zone; the evaporation zone is located at one end of the shell (1), the condensation zone is located at the other end of the shell (1), and one end of the shell (1) and the other end of the shell (1) are the two ends of the shell (1) along the length direction; A liquid-absorbing core (3) is disposed in the inner cavity (2), and the liquid-absorbing core (3) is spaced apart from the top of the housing (1); The phase change working fluid (4) is filled in the inner cavity (2). It can release heat and condense into a liquid in the condensation zone and then flow from the condensation zone to the evaporation zone under the capillary action of the liquid suction core (3). It can also absorb heat and evaporate into a gas in the evaporation zone and then flow from the evaporation zone to the condensation zone under the action of the gas pressure difference. A pump-driven system (5) is used to drive the liquid phase change working fluid (4) to flow from the condensation zone to the evaporation zone.

2. The phase change heat transfer device according to claim 1, characterized in that, The pump drive system (5) includes a piezoelectric pump (501), which has a liquid intake port (508) and a liquid discharge port (509). The liquid intake port (508) is connected to the condensation zone, and the liquid discharge port (509) is connected to the evaporation zone. The piezoelectric pump (501) is used to drive the flow of the liquid phase change working fluid (4). The piezoelectric pump (501) is disposed in the inner cavity (2); or, the piezoelectric pump (501) is disposed on the side of the housing (1) away from the inner cavity (2), and the housing (1) has a first communication port and a second communication port; the liquid extraction port (508) is connected to the condensation zone through the first communication port, and the liquid discharge port (509) is connected to the evaporation zone through the second communication port.

3. The phase change heat transfer device according to claim 2, characterized in that, The pump drive system (5) also includes a flow guide seat (502) and a flow guide pipe (503); The flow guide seat (502) is disposed in the inner cavity (2) and located in the condensation zone. The flow guide seat (502) has a first liquid inlet (504), a first liquid outlet (505), a second liquid inlet (506) and a second liquid outlet (507) for guiding the flow direction of the liquid phase change working fluid (4). The first liquid inlet (504) is connected to the first liquid outlet (505), and the second liquid inlet (506) is connected to the second liquid outlet (507). The piezoelectric pump (501) is connected to the guide seat (502), the liquid extraction port (508) is connected to the first liquid outlet (505), and the liquid discharge port (509) is connected to the second liquid inlet (506). The guide tube (503) has an inlet end (510) and an outlet end (511) for cooperating with the guide seat (502) to guide the liquid phase change working medium (4) to the evaporation zone; the inlet end (510) is connected to the second liquid outlet (507), and the outlet end (511) extends to the evaporation zone.

4. The phase change heat transfer device according to claim 3, characterized in that, The guide tube (503) is positioned above the liquid-absorbing core (3); or, The guide tube (503) is disposed inside the liquid suction core (3).

5. The phase change heat transfer device according to claim 3, characterized in that, The bottom of the flow guide seat (502) is provided with a groove (512), and the groove (512) and the bottom inner side of the shell (1) form a liquid collection chamber (513). The first liquid inlet (504) is located at the bottom of the groove (512).

6. The phase change heat transfer device according to claim 5, characterized in that, The bottom of the housing (1) has a bent structure, which includes a first wall (101), a second wall (102) and a third wall (103). The first distance is less than the second distance. The first distance is the distance between the first wall (101) and the top of the housing (1), and the second distance is the distance between the second wall (102) and the top of the housing (1). The first wall (101) and the second wall (102) are connected by the third wall. The groove (512) is disposed opposite to the second wall (102) to form a liquid-gathering chamber (513).

7. The phase change heat transfer device according to claim 5, characterized in that, It also includes a control module; The control module is electrically connected to the piezoelectric pump (501) and is used to control the start and stop of the piezoelectric pump (501) and / or adjust the operating parameters of the piezoelectric pump (501); The control module includes a manual control unit, which can be manually operated to control the start and stop of the piezoelectric pump (501) and / or adjust the operating parameters of the piezoelectric pump (501). Alternatively, the control module may include an automatic control unit and a temperature sensor; The automatic control unit is connected to the temperature sensor and is used to automatically control the start and stop of the piezoelectric pump (501) and / or adjust the operating parameters of the piezoelectric pump (501) according to the temperature parameters of the heat source collected by the temperature sensor. Alternatively, the control module may include an automatic control unit and a power detector; The automatic control unit is connected to the power detector and is used to automatically control the start and stop of the piezoelectric pump (501) and / or adjust the operating parameters of the piezoelectric pump (501) according to the power parameters of the heat source collected by the power detector. Alternatively, the control module may include an automatic control unit and a water level detector; The water level detector is located at the bottom of the groove (512) and is used to issue a start signal after detecting that the liquid phase change working medium (4) accumulated in the liquid accumulation chamber (513) has reached a specified water level. The automatic control unit is connected to the water level detector and is used to automatically control the start and stop of the piezoelectric pump (501) and / or adjust the operating parameters of the piezoelectric pump (501) after receiving the start signal.

8. The phase change heat transfer device according to claim 1, characterized in that, The inner wall of the housing (1) located in the condensation zone is provided with a hydrophobic surface layer.

9. The phase change heat transfer device according to claim 2, characterized in that, The pump drive system (5) also includes a separator (104). The partition (104) is located inside the inner cavity (2). The partition (104) includes a first side (1041) and a second side (1042). The first side (1041) is the side facing the condensation zone, and the second side (1042) is the side facing away from the condensation zone. The piezoelectric pump (501) is used to drive the liquid phase change working fluid (4) from the condensation zone to the target cavity, which is constructed based on the second side (1042) and is connected to the evaporation zone.

10. The phase change heat transfer device according to claim 3, characterized in that, The outlet end (511) has a porous atomization structure.

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