A heat dissipation system of a triple-loop heat pipe

Abstract

This invention provides a heat dissipation system with a tertiary loop heat pipe, comprising a cooling tower, a heat exchange unit, an immersion cooling chamber, and a heat source. The cooling tower and the heat exchange unit are thermally connected via a primary loop, the heat exchange unit and the immersion cooling chamber are thermally connected via a secondary loop, and the immersion cooling chamber and the heat source are thermally connected via a tertiary loop. The tertiary loop is a loop heat pipe, wherein the evaporator end of the loop heat pipe is thermally connected to the heat source to absorb heat, and the condenser end of the loop heat pipe is located within the immersion cooling chamber. This invention's heat dissipation system adds a tertiary gas-liquid circulation pipeline, allowing the heat exchange unit inside the immersion cooling chamber to be immersed within the chamber, enhancing heat transfer and improving overall heat dissipation efficiency.

Description

Technical Field

[0001] This invention relates to a heat pipe technology, and more particularly to a loop heat pipe for waste heat recovery, belonging to the field of heat pipes F28d15 / 02. Background Technology

[0002] A heat exchanger is a device that exchanges heat between hot and cold fluids. Heat exchangers are widely used in many fields. In industries such as electronics, petrochemicals, communications, and aerospace, due to their unique operating environments, there are special requirements for the size and weight of heat exchangers, as well as a higher heat exchange capacity.

[0003] A heat pipe is a type of heat exchanger, a heat transfer element that fully utilizes the principles of heat conduction and the rapid heat transfer properties of phase change media. Through the heat pipe, the heat of the heated object is quickly transferred to the outside of the heat source, and its thermal conductivity exceeds that of any known metal.

[0004] Heat pipe technology was previously widely used in aerospace and military industries. Since its introduction into the radiator manufacturing industry, it has revolutionized traditional radiator design, moving beyond the reliance on high-airflow motors for better heat dissipation. Heat pipe technology has enabled radiators to achieve satisfactory heat exchange, opening up new possibilities in the heat dissipation industry. Currently, heat pipes are widely used in various heat exchange equipment.

[0005] A loop heat pipe is a type of closed-loop heat pipe. It typically consists of an evaporator, a condenser, a receiver, and vapor and liquid lines. Its working principle is as follows: a heat load is applied to the evaporator, causing the fluid to evaporate on the outer surface of the evaporator capillary wick. The resulting vapor flows out of the vapor channel and into the vapor line, then enters the condenser where it condenses into liquid and is subcooled. The returning liquid flows through the liquid line into the liquid main channel to replenish the evaporator capillary wick. This cycle continues, driven by the capillary pressure generated by the evaporator capillary wick, requiring no external power. Because the condensation and evaporation sections are separate, loop heat pipes are widely used in integrated energy applications, heat dissipation systems, and waste heat recovery.

[0006] CN116858002A discloses a waste heat recovery loop heat pipe system and method, including a preheater, evaporator, condenser, liquid receiver, pump, and regenerator. The preheater, evaporator, condenser, and liquid receiver are connected sequentially by pipelines. The liquid receiver is connected to the regenerator by a pipeline. A pump is installed on the pipeline between the liquid receiver and the regenerator. The regenerator is connected to the preheater by a pipeline. This invention improves upon current loop heat pipes by proposing a novel waste heat recovery type pump-driven two-phase loop heat pipe. Based on mechanical pump-driven two-phase fluid loop technology and waste heat recovery technology, it meets high heat dissipation requirements and can recover and utilize waste heat.

[0007] CN117570760A discloses a high-efficiency heat exchange phase change energy storage system based on cryogenic fluids, including an energy storage tank, an energy release heat exchanger, and an energy storage heat exchanger. The high-efficiency heat exchange phase change energy storage system of this invention is a phase change energy storage cycle. By switching control, the energy storage cycle and the energy release cycle share a single system pipeline, simplifying the system layout. The heat exchange plate assembly in the energy storage tank can simultaneously handle energy storage and energy release heat exchange, improving heat exchange efficiency and increasing the effective heat exchange space within the energy storage tank, thus reducing the tank volume by more than one-third.

[0008] Cold plate liquid cooling offers high reliability and strong heat dissipation capacity, but because its cooling plate is directly connected to the secondary fluid circuit, it suffers from scaling, contamination, and blockage over long-term operation; furthermore, it currently only allows for overall cooling and cannot achieve point-to-point cooling. Immersion cooling, while offering strong overall heat dissipation capacity, has lower efficiency in dissipating heat from individual heat sources. Therefore, upgrading existing cooling systems to ensure safe and efficient operation and achieve energy conservation and emission reduction is of great significance. Summary of the Invention

[0009] The purpose of this invention is to provide a heat dissipation system with a three-loop heat pipe, which can improve the system's heat dissipation capacity, reduce the power consumption of the cooling system, and ensure adaptive point cooling for different heat sources.

[0010] Adaptive point-to-point cooling is achieved through the coupling of a "chip-level double-sided phase change microchannel evaporator + tertiary side-closed two-phase loop". The basic mechanism is as follows: the phase change microchannel evaporation structure is directly thermally coupled to the target heat source, causing the heat generated by the heat source to locally induce preferential boiling and vaporization of the working fluid, forming vapor which is transported along the two-phase loop to the distant condensation heat exchange unit for condensation. The condensed liquid working fluid, under the combined action of gravity and the two-phase pressure difference, flows back to replenish the evaporation zone, thus forming a closed loop of "evaporation-transportation-condensation-reflux". Since the driving force of the two-phase loop is positively correlated with the vaporization intensity, when the heat load of a certain heat source increases, its local vaporization increases, the loop pressure difference increases, and the circulation flow rate increases accordingly, automatically concentrating the cooling capacity towards that hot spot. When the load of a certain heat source decreases or it shuts down, its vaporization intensity decreases, the corresponding branch loop automatically weakens or even tends to stop, and cooling resources naturally transfer to other high-load heat sources. Therefore, it is not necessary to provide overall high-flow cooling for all chips, but can achieve point-to-point cooling that automatically distributes cooling capacity according to changes in heat load. Under extreme high heat flux or rapid load transition conditions, it can also switch to pump-driven forced circulation to improve liquid supply capacity and stability, thereby reducing the power consumption of the cooling system while ensuring adaptive point-to-point cooling effect for different heat sources.

[0011] To achieve the above objectives, the technical solution of the present invention is as follows: A heat dissipation system with a three-loop heat pipe includes a cooling tower, a heat exchange unit, an immersion cooling chamber, and a heat source. The cooling tower and the heat exchange unit are thermally connected through a primary circulation loop, the heat exchange unit and the immersion cooling chamber are thermally connected through a secondary circulation loop, and the immersion cooling chamber and the heat source are thermally connected through a tertiary circulation loop. The tertiary circulation loop is a loop heat pipe, wherein the evaporation end of the loop heat pipe is thermally connected to the heat source to absorb heat from the heat source, and the condensation end of the loop heat pipe is disposed in the immersion cooling chamber.

[0012] As an improvement, in the secondary circulation loop, the cold fluid is driven by the drive pump to enter the immersion cooling tank through the secondary side cold fluid pipeline, where it exchanges heat with the condenser end of the loop heat pipe. The heated hot fluid then flows back to the heat exchange unit through the secondary side hot fluid pipeline and is cooled, thus completing the cycle.

[0013] As an improvement, in the primary circulation loop, the cold fluid flows into the heat exchange unit through the primary side cold fluid pipeline, and the hot fluid after heat exchange is completed flows into the cooling tower through the primary side hot fluid pipeline to be cooled. The cooling tower achieves heat exchange with the external environment.

[0014] As an improvement, the loop heat pipe condenser end includes multiple loop heat pipe condenser ends, which are arranged in multiple rows in the vertical direction within the immersion cooling box.

[0015] As an improvement, the condenser ends of the loop heat pipes are arranged in a staggered manner in the vertical direction.

[0016] As an improvement, the spacing between the condenser ends of adjacent loop heat pipes gradually increases from top to bottom.

[0017] As an improvement, the spacing between the condensing ends of adjacent loop heat pipes gradually increases from top to bottom.

[0018] As an improvement, the evaporation section of the loop heat pipe is a double-sided manifold microchannel heat exchanger.

[0019] As an improvement, the evaporation section of the loop heat pipe includes, from top to bottom, an upper microchannel substrate, an upper sealing frame, an upper fluid distribution plate, a middle manifold core, a lower fluid distribution plate, a lower sealing frame, and a lower microchannel substrate. The upper and lower microchannel substrates respectively constitute the heat exchange substrates for the upper and lower chips, with phase change microchannel heat exchange zones formed on their inner sides. The upper and lower sealing frames respectively cooperate with the corresponding microchannel substrates to form upper and lower closed flow channel cavities. The upper and lower fluid distribution plates are respectively attached to the inner sides of the corresponding microchannel substrates, each having a central linear liquid inlet groove extending along its length and left and right linear collecting grooves arranged on both sides of the liquid inlet groove, used to introduce liquid working fluid from the center and collect and discharge the vapor or vapor-liquid mixture generated by the phase change on both sides. The intermediate manifold core is provided with a central wedge-shaped liquid inlet cavity that communicates with the external liquid inlet, and left and right wedge-shaped collecting cavities arranged at the left and right ends of the liquid inlet cavity and communicating with the external liquid outlet. The central wedge-shaped liquid inlet cavity and the left and right wedge-shaped collecting cavities are not directly connected to each other. The central wedge-shaped liquid inlet cavity is connected to the middle linear liquid inlet groove of the upper fluid distribution plate and the lower fluid distribution plate, respectively, so that the liquid working fluid entering from the liquid inlet is simultaneously distributed to the middle liquid inlet groove on the upper and lower sides in the intermediate manifold layer, and further enters the phase change microchannel heat exchange zone of the upper and lower microchannel substrates. The liquid working fluid absorbs heat, boils and vaporizes in the phase change microchannel heat exchange zone to form steam or vapor-liquid two phases, and flows from the middle to both sides along the microchannel, and then flows into the left and right linear collecting grooves of the upper and lower fluid distribution plates, respectively. The left and right wedge-shaped collecting cavities are connected to the left and right linear collecting grooves of the upper and lower fluid distribution plates, respectively, to collect the steam or vapor-liquid mixture from the upper and lower sides, and then discharge it from the liquid outlet after merging inside the intermediate manifold core.

[0020] As an improvement, the loop heat pipe is equipped with a backup liquid-driven pump and an automatic regulating valve. Under low heat load, the loop is passively driven by gravity and buoyancy by opening the automatic regulating valve; under high heat load, the working fluid is forcibly driven by closing the automatic regulating valve and opening the backup liquid-driven pump.

[0021] Compared with the prior art, the present invention has the following advantages: This invention integrates a double-sided phase-change microchannel heat sink into a primary-secondary-tertiary staged cooling architecture in a data center. A closed tertiary two-phase loop is constructed on the chip side, allowing the cooling capacity to automatically adjust according to the heat source vaporization intensity and prioritize high-heat-load chips. This achieves adaptive, point-to-point cooling, avoiding the energy waste caused by traditional cold-plate liquid cooling's large-flow overall cooling of all chips. Simultaneously, under normal operating conditions, the tertiary two-phase loop can form a natural circulation through phase-change pressure difference and gravity reflux. The secondary side only needs to provide forced heat exchange to the condensation heat exchange unit within the immersed cooling tank. This significantly reduces the overall circulation pressure drop and pump power, which helps reduce cooling system power consumption and improve performance. Data center PUE; In addition, the chip-side working fluid loop and the secondary-side circulating liquid are isolated from each other, and the secondary-side coolant does not directly enter the microchannel structure, which can effectively reduce the risk of scaling, contamination and blockage, improve long-term operational reliability and reduce maintenance costs; Furthermore, the double-sided microchannel phase change structure has a high specific surface area and enhanced boiling heat transfer capability, which can simultaneously cool the upper and lower chips in a compact space and improve the heat dissipation capacity per unit volume. Combined with the manifold diversion and steam pooling buffer structure, it can also suppress temperature and pressure fluctuations caused by load fluctuations. Under extreme high heat flux conditions, it can switch to forced circulation mode to further enhance the liquid supply and exhaust capacity, thereby achieving efficient heat dissipation, low power consumption and high reliability. Attached Figure Description

[0022] Figure 1 It is the heat dissipation system of the background technology; Figure 2 This is a schematic diagram of the loop heat pipe cooling system of this application; Figure 3 This is a schematic diagram of the immersion cooling tank structure of the present invention; Figure 4 This is a structural diagram of a three-stage gas-liquid circulation loop; Figure 5 This is a schematic diagram of the overall and split structure of the optimized loop heat pipe evaporator end of the present invention; Figure 6 This is a schematic diagram of the microchannel substrate structure on the evaporator end of the loop heat pipe of the present invention. Figure 7 This is a schematic diagram of the sealing frame structure on the evaporator end of the loop heat pipe of the present invention; Figure 8 This is a schematic diagram of the grooved fluid distribution plate structure at the evaporator end of the loop heat pipe of the present invention; Figure 9 Schematic diagram of the double-sided manifold core plate structure at the evaporator end of the loop heat pipe; Figure 10 This is a schematic diagram of the overall flow of the heat exchanger.

[0023] Figure label: 1 Cooling tower; 11 Primary side cold fluid piping; 12 Primary side hot fluid piping; 2 Heat exchange unit; 21 Secondary side cold fluid piping; 22 Secondary side hot fluid piping; 3 Immersion cooling chamber; 31 Tertiary side gas-liquid circulation piping; 32 Heat source; 221 Immersion cooling chamber cold fluid distribution pipe; 222 Immersion cooling chamber hot fluid distribution pipe; 223 Immersion cooling chamber cold fluid distribution pipe; 33 Loop heat pipe condenser end; 34 Loop heat pipe evaporator end; 35 Standby liquid drive pump; 36 Automatic regulating valve; 311 Tertiary side circulation loop cold fluid piping; 312 Tertiary side circulation loop hot fluid piping; 341 Upper microchannel substrate; 3411 Upper substrate; 3412 Upper microchannel substrate Channels; 342 Upper sealing frame, 3421 Upper microchannel mounting groove; 343 Upper grooved fluid distribution plate, 3431 Upper left return groove, 3432 Upper middle inlet groove, 3433 Upper right return groove; 344 Double-sided manifold core plate, 3441 Left side return manifold cavity, 3442 Outlet, 3443 Right side return manifold cavity, 3444 Inlet, 3445 Inlet guide wedge, 3446 Return cavity connecting channel; 345 Lower grooved fluid distribution plate, 3451 Lower left return groove, 3452 Lower middle inlet groove, 3453 Lower right return groove; 346 Lower sealing frame, 3461 Lower microchannel mounting groove; 347 Lower microchannel substrate, 3471 Lower substrate, 3472 Lower microchannel. Detailed Implementation

[0024] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0025] Fluid inlet Fluid outlet Fluid inlet Fluid outlet Figure 2-4 A three-loop heat pipe cooling system is demonstrated. For example... Figure 2 As shown, a heat dissipation system of a three-loop heat pipe includes a cooling tower 1, a heat exchange unit 2, an immersion cooling chamber 3, and a heat source 4. The cooling tower 1 and the heat exchange unit 2 are thermally connected through a primary circulation loop, the heat exchange unit 2 and the immersion cooling chamber 3 are thermally connected through a secondary circulation loop, and the immersion cooling chamber 3 and the heat source 4 are thermally connected through a tertiary circulation loop 31. The tertiary circulation loop is a loop heat pipe 32, wherein the evaporation end 34 of the loop heat pipe is thermally connected to the heat source 4 to absorb heat from the heat source, and the condensation end 33 of the loop heat pipe is disposed in the immersion cooling chamber 3.

[0026] Compared to Figure 1 Compared with the heat dissipation system in the background technology, the heat dissipation system of the present invention adds a tertiary gas-liquid circulation pipeline, and the condensing end 33 of the loop heat pipe is set in the fluid immersed in the cooling box 3 to enhance heat transfer and improve the overall heat dissipation efficiency.

[0027] As an improvement, the loop heat pipe utilizes the gravity and buoyancy generated by phase change heat transfer technology as the circulation power for the tertiary gas-liquid circulation pipeline. As another improvement, the design height difference between the condenser end 33 and the evaporator end inside the immersion cooling chamber is 30 cm. By setting this height difference, the effects of gravity and buoyancy are enhanced, further improving circulation efficiency.

[0028] As an improvement, in the secondary circulation loop, the cold fluid is driven by the drive pump to enter the immersion cooling box through the secondary side cold fluid pipeline 21, where it exchanges heat with the condenser end of the loop heat pipe. The heated fluid then flows back to the heat exchange unit through the secondary side hot fluid pipeline 22 and is cooled, thus completing the cycle.

[0029] As an improvement, in the primary circulation loop, the cold fluid flows into the heat exchange unit 2 through the primary side cold fluid pipeline 11, and the hot fluid after heat exchange is completed flows into the cooling tower through the primary side hot fluid pipeline 12 to be cooled. The cooling tower achieves heat exchange with the external environment.

[0030] The heat exchange unit uses indirect heat exchangers, such as shell-and-tube or plate heat exchangers. The cooling tower is a dry cooling tower.

[0031] As an improvement, the loop heat pipe condenser ends include multiple units, which are arranged in multiple rows vertically within the immersion cooling chamber. This multi-row structure allows for simultaneous heat dissipation from multiple heat sources.

[0032] As an improvement, such as Figure 3 As shown, the cold fluid enters from the lower part of the secondary side immersion cooling box, and the hot fluid, after heat exchange, flows into the heat exchange unit from the upper part of the cooling box. From top to bottom, the spacing between the condenser ends of adjacent loop heat pipes gradually increases. This is mainly because the fluid temperature at the bottom is the lowest, resulting in the best heat exchange effect. Therefore, the condenser ends are designed with a higher density and greater heat distribution density, while the upper part has a lower heat exchange density and poorer heat exchange effect, thus promoting uniform heat exchange overall and avoiding poor heat exchange performance in some condenser ends.

[0033] As an improvement, the spacing between the condenser ends of adjacent heat pipes in the top-to-bottom direction gradually increases. By setting this variation in spacing, overall heat transfer uniformity can be further promoted.

[0034] As an improvement, the condenser ends of the loop heat pipes are arranged in a staggered configuration in the vertical direction. This staggered arrangement allows the fluid moving within the submerged chamber to form a zigzag flow, thereby promoting heat transfer.

[0035] As an improvement, along the height direction, the condensing end is arranged in a baffle structure within the submerged chamber; that is, the condensing end extends from both side walls of the chamber to form a baffle structure. This causes the heat exchange fluid to flow along the bend, thereby further increasing the contact area and improving the heat exchange effect.

[0036] As an improvement, the heat source can be selected from industrial waste heat, building waste heat, high-temperature flue gas, power plant exhaust steam, or data center.

[0037] As an improvement, the evaporation section of the loop heat pipe is a double-sided manifold microchannel heat exchanger.

[0038] The terms "front," "back," "left," and "right" used in the following descriptions do not represent actual directions; they are merely for ease of description. "Front" and "back" are based on the direction of liquid flow; "front" indicates the direction of the fluid inlet, and "back" indicates the direction of the fluid outlet. "Left" and "right" are based on the two sides of the inlet guide wedge. Figure 5 , 9 The left and right sides of the inlet guide wedge viewed from the fluid inlet direction towards the fluid outlet direction.

[0039] Figure 5-10 A bi-faced manifold microchannel heat exchanger is demonstrated. For example... Figure 5 As shown, the double-sided manifold microchannel heat exchanger includes, from top to bottom, an upper microchannel substrate 341, an upper sealing frame 342, an upper fluid distribution plate 343, a middle manifold core 344, a lower fluid distribution plate 345, a lower sealing frame 346, and a lower microchannel substrate 347. The upper microchannel substrate 341 and the lower microchannel substrate 347 respectively constitute the heat exchange substrates of the upper and lower chips, and a phase change microchannel heat exchange zone is formed on their inner sides. The upper sealing frame 342 and the lower sealing frame 346 respectively cooperate with the corresponding microchannel substrates to form upper and lower closed flow channel cavities. The upper fluid distribution plate 343 and the lower fluid distribution plate 345 are provided with a central linear inlet groove 3432 and 3452 extending along the front-to-back length direction, and left and right linear return grooves 3431, 3433, 3451 and 3453 arranged on both sides of the inlet groove; the middle manifold core 344 is provided with a central wedge-shaped inlet cavity 3445 communicating with the external fluid inlet 3444, and left and right wedges arranged at the left and right ends of the inlet cavity, communicating with the external fluid outlet 3442 through the return cavity connection channel 3446. The return cavities 3441 and 3443 are not directly connected to the inlet cavity and the return cavity. The inlet cavity is connected to the middle linear inlet groove on the upper fluid distribution plate and the lower fluid distribution plate, so that the coolant entering from the fluid inlet is distributed to the middle inlet groove on the upper and lower sides in the middle manifold layer. The left and right wedge-shaped return cavities are connected to the left and right linear return grooves on the upper fluid distribution plate and the lower fluid distribution plate, respectively. They are used to collect the coolant that flows from the middle to the sides through the upper and lower microchannels and then merges into the return groove. After merging inside the middle manifold core, it is discharged from the fluid outlet.

[0040] This invention provides a single-inlet, single-outlet manifold assembly for a double-sided phase change microchannel heat exchange structure. While maintaining a simple structure and compact size, this manifold assembly allows liquid working fluid to enter through a single inlet, be distributed to the upper and lower sides within a middle manifold layer, and then enter the upper and lower phase change microchannel heat exchange structures respectively. The working fluid absorbs heat and boils / vaporizes within the microchannel, forming vapor or a vapor-liquid two-phase flow from the center to both sides. After converging on both sides, it re-converges through the middle manifold layer and exits through a single outlet. This structure allows for simultaneous phase change cooling of heat sources in both directions without increasing the number of external pipes, improving heat transfer capacity and heat dissipation efficiency per unit volume, simplifying system connections, and reducing flow pressure drop and temperature distribution unevenness.

[0041] With the above structure, the same set of inlets and outlets can complete the liquid supply and collection of the phase change microchannel heat exchange structure on both sides, realizing synchronous phase change cooling of the double-sided heat source; the liquid working fluid is distributed to the upper and lower sides by the middle manifold and enters the microchannel from the middle. After absorbing heat and boiling in the microchannel to form steam or vapor-liquid two phases, it is collected on both sides and then merged through the middle manifold and discharged to the condensing section for cooling and condensation and reflux. This not only helps to improve the uniformity of liquid supply in each microchannel and reduce the risk of drying out, but also improves the uniformity of temperature field distribution and enhances the overall heat exchange efficiency.

[0042] As an improvement, such as Figure 9 As shown, the fluid inlet 3444 and the fluid outlet 3442 are respectively located on the front and rear sides of the intermediate manifold core.

[0043] As an improvement, such as Figure 9 As shown, the wedge-shaped wide portion of the wedge-shaped inlet cavity 3445 is connected to the fluid inlet, and the wedge-shaped tip is located away from the fluid inlet.

[0044] By connecting the wedge-shaped wide portion of the wedge-shaped inlet cavity 3445 to the inlet and arranging the wedge-shaped tip towards the direction away from the inlet, the coolant entering the radiator gradually transitions from a large cross-section to a small cross-section within the wedge-shaped inlet cavity. This avoids the strong impact and flow separation caused by the sudden narrowing of the channel, and facilitates the formation of a relatively gentle and uniform pressure distribution along the length of the wedge-shaped inlet cavity. This improves the flow distribution at the microchannel inlet at different locations and reduces the local flow resistance on the inlet side.

[0045] As an improvement, a connecting channel 3446 is provided between the left and right wedge-shaped return cavities. The connecting channel is connected to the fluid outlet 3442. The wedge-shaped wide part of the wedge-shaped return cavity is connected to the connecting channel, and the wedge-shaped tip of the wedge-shaped return cavity is away from the direction of the connecting channel.

[0046] By setting a connecting channel 3446 between the left and right wedge-shaped return cavities and communicating with the outlet 3442, and arranging the wedge-shaped wide part of the return cavity to be connected to the connecting channel and the wedge-shaped tip away from the connecting channel, the coolant flowing out of each microchannel enters from the far end of the return cavity and gradually increases the channel cross-section and gradually decreases the flow velocity as it flows towards the connecting channel. This reduces the local pressure drop and eddies on the outlet side, making it easier for the return flows on both sides to mix fully and flow evenly into the outlet in the area near the connecting channel, thereby improving the stability of the return flow and the consistency of the outlet flow distribution.

[0047] Because the cross-section of the wedge-shaped inlet cavity 3445 gradually decreases in width along the main flow direction of the coolant, while the cross-section of the wedge-shaped return cavities 3441 and 3443 gradually increases in width along the main flow direction of the coolant, their wedge-shaped directions are opposite, forming a complementary pressure gradient distribution on the inlet and outlet sides of the microchannel. On the one hand, the tapering structure on the inlet side helps to suppress excessive flow near the inlet end of the channel and increase the supply pressure of the distal channel; on the other hand, the expanding structure on the return side weakens the excessive suction effect near the outlet end of the channel and improves the return capacity of the distal channel. Through this wedge-shaped combination in opposite directions, the flow distortion on both sides of the microchannel inlet and outlet can be improved simultaneously, allowing microchannels arranged in different positions to obtain a more uniform pressure differential driving force, thereby improving the flow distribution within the channel and the uniformity of the chip surface temperature field.

[0048] As an improvement, such as Figure 9 As shown, the fluid outlet is further back than the wedge-shaped wide portion of the wedge-shaped return cavity, thus forming a bend in the channel towards the return cavity.

[0049] By arranging the outlet 3442 further back than the wedge-shaped width of the return cavity, the connecting channel 3446 forms a bend towards the return cavity on the side closest to it. This extends the flow path of the coolant from the left and right wedge-shaped return cavities to the outlet and introduces appropriate local resistance at the bend. This structure, on the one hand, reduces the direct suction effect of the outlet on the return cavity on the side closest to it, avoiding a "short-circuit" phenomenon where the return flow on one side is significantly larger; on the other hand, it facilitates the remixing and balancing of the fluids from the left and right return cavities within the connecting channel, thereby further improving the uniformity of flow rate and temperature at the outlet.

[0050] As an improvement, the flow area of ​​the wedge-shaped inlet chamber and / or wedge-shaped return chamber gradually decreases from top to bottom. Since the heat exchanger is arranged vertically, the fluid flow direction is preferably downwards due to gravity. This application, by setting the flow area to gradually decrease vertically, reduces the lower flow area and increases the lower flow resistance, allowing the fluid to flow upwards during distribution. This ensures uniform distribution of the fluid vertically, enabling balanced heat release from both the upper and lower heat sources and avoiding uneven heat exchange caused by uneven vertical distribution.

[0051] As an improvement, the flow area of ​​the wedge-shaped inlet chamber and / or wedge-shaped return chamber gradually decreases from top to bottom, with the rate of decrease gradually increasing. This invention, through the variation in area size, can further achieve uniform fluid distribution between the upper and lower parts of the body, thereby ensuring effective heat exchange.

[0052] As an improvement, the capillary suction force of the microchannel structure inside the upper sealing frame is greater than that of the microchannel structure inside the lower sealing frame. Because the fluid enters the left and right linear return channels from the central linear inlet channels 3432 and 3452 through capillary suction, and because the heat exchanger is arranged vertically, the fluid flow direction is preferably downwards due to gravity. Therefore, by increasing the capillary suction force at the top, the liquid suction capacity at the top can be increased, thereby ensuring a uniform distribution of the fluid in the vertical direction. This allows both the upper and lower heat sources to release heat evenly, avoiding uneven heat exchange caused by uneven distribution in the vertical direction.

[0053] As an improvement, the microchannel structure is directly formed on the upper microchannel substrate and the lower microchannel substrate.

[0054] As an improvement, the microchannel structure is a separate structure from the upper and lower sealing frames. The inner sides of both the upper and lower sealing frames are machined with grooves for placing the microchannel cooling structure.

[0055] The work process is as follows: like Figure 8 , Figure 9As shown, during use, the liquid working fluid first flows into the central wedge-shaped inlet cavity 3445 inside the central manifold core 344 through the fluid inlet device arranged on the side wall of the central manifold core 344. After spreading along the length direction in the central wedge-shaped inlet cavity 3445, the liquid working fluid flows into the upper central inlet groove 3432 in the middle of the upper fluid distribution plate 343 and the lower central inlet groove 3452 in the middle of the lower fluid distribution plate 345 through the connecting holes provided on the upper and lower surfaces of the cavity, and is distributed along the length direction of the groove. Subsequently, the liquid working fluid enters the upper and lower phase change microchannel structures through the upper and lower central inlet grooves 3432 and 3452 through the corresponding upper and lower microchannel inlets, where it absorbs heat and boils and vaporizes, forming a vapor or vapor-liquid two-phase system that flows from the middle to the left and right sides, and undergoes phase change heat exchange with the chip surfaces arranged on both sides of the device.

[0056] The vapor or vapor-liquid phases generated by the phase change enter the upper left collecting tank 3431 and the upper right collecting tank 3433 from the upper microchannel outlet, and the lower left collecting tank 3451 and the lower right collecting tank 3453 from the lower microchannel outlet, and are collected along the length of each collecting tank to both ends of the device. The collected vapor or vapor-liquid phases enter the left and right wedge-shaped collecting cavities 3441 and 3443 inside the intermediate manifold core 344 through the connecting holes between the upper and lower fluid distribution plates 343 and 345 and the intermediate manifold core 344, respectively. After further merging in the left and right wedge-shaped collecting cavities 3441 and 3443, they are introduced into the outlet channel 3446 located in the middle, and finally through the fluid outlet 3442 arranged on the side wall of the intermediate manifold core 344. The fluid is discharged from the device and enters the external condensation heat exchange section, where it exchanges heat with the cooling medium and condenses into a liquid working fluid. Then, under the action of gravity and the two-phase pressure difference, it flows back to the fluid inlet side, realizing a closed two-phase circulation.

[0057] Through the above flow process, the working fluid can simultaneously supply and collect liquid to the upper and lower phase change microchannel structures inside the device using only a single fluid inlet and a single fluid outlet, forming a circulating flow organization of "liquid supply in the middle - phase change heat transfer in the upper / lower microchannels - collection on both sides - merging and outlet in the middle - external condensation and reflux". This balances structural compactness, circulation resistance and uniformity of double-sided cooling, while reducing the risk of local drying and improving overall heat exchange efficiency.

[0058] While the present invention has been disclosed above with reference to preferred embodiments, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A heat dissipation system of a three-loop heat pipe, comprising a cooling tower, a heat exchange unit, an immersion cooling chamber, and a heat source; the cooling tower and the heat exchange unit are thermally connected through a primary circulation loop, the heat exchange unit and the immersion cooling chamber are thermally connected through a secondary circulation loop, and the immersion cooling chamber and the heat source are thermally connected through a tertiary circulation loop, wherein the tertiary circulation loop is a loop heat pipe, wherein the evaporation end of the loop heat pipe is thermally connected to the heat source to absorb heat from the heat source, and the condensation end of the loop heat pipe is disposed in the immersion cooling chamber.

2. The heat dissipation system as described in claim 1, characterized in that, In the secondary circulation loop, the cold fluid is driven by the drive pump to enter the immersion cooling tank through the secondary side cold fluid pipeline, where it exchanges heat with the condenser end of the body loop heat pipe. The heated fluid then flows back to the heat exchange unit through the secondary side heat fluid pipeline and is cooled, thus completing the cycle.

3. The heat dissipation system as described in claim 2, characterized in that, In a single circulation loop, the cold fluid flows into the heat exchange unit through the primary side cold fluid pipeline, and the hot fluid after heat exchange flows into the cooling tower through the primary side hot fluid pipeline to be cooled. The cooling tower achieves heat exchange with the external environment.

4. The heat dissipation system as described in claim 2, characterized in that, The loop heat pipe condenser end includes multiple loop heat pipe condenser ends, which are arranged in multiple rows in the vertical direction within the immersion cooling chamber.

5. The heat dissipation system as described in claim 4, characterized in that, In the vertical direction, the condenser ends of the loop heat pipes are arranged in a staggered pattern.

6. The heat dissipation system as described in claim 4, characterized in that, From top to bottom, the distance between the condenser ends of adjacent loop heat pipes gradually increases.

7. The heat dissipation system as described in claim 6, characterized in that, From top to bottom, the distance between the condensing ends of adjacent loop heat pipes gradually increases.

8. The heat dissipation system as described in claim 2, characterized in that, The evaporation section of the loop heat pipe is a double-sided manifold microchannel heat exchanger.

9. The heat dissipation system as described in claim 8, characterized in that, The evaporation section of the loop heat pipe includes, from top to bottom, an upper microchannel substrate, an upper sealing frame, an upper fluid distribution plate, a middle manifold core, a lower fluid distribution plate, a lower sealing frame, and a lower microchannel substrate. The upper and lower microchannel substrates respectively constitute the heat exchange substrates for the upper and lower chips, with phase change microchannel heat exchange zones formed on their inner sides. The upper and lower sealing frames respectively cooperate with the corresponding microchannel substrates to form upper and lower closed flow channel cavities. The upper and lower fluid distribution plates are respectively attached to the inner sides of the corresponding microchannel substrates, each having a central linear liquid inlet groove extending along its length and left and right linear collecting grooves arranged on both sides of the liquid inlet groove. These grooves are used to introduce liquid working fluid from the center and collect and discharge the vapor or vapor-liquid mixture generated by the phase change on both sides. The intermediate manifold core is provided with a central wedge-shaped liquid inlet cavity that communicates with the external liquid inlet, and left and right wedge-shaped collecting cavities arranged at the left and right ends of the liquid inlet cavity and communicating with the external liquid outlet. The central wedge-shaped liquid inlet cavity and the left and right wedge-shaped collecting cavities are not directly connected to each other. The central wedge-shaped liquid inlet cavity is connected to the middle linear liquid inlet groove of the upper fluid distribution plate and the lower fluid distribution plate, respectively, so that the liquid working fluid entering from the liquid inlet is simultaneously distributed to the middle liquid inlet groove on the upper and lower sides in the intermediate manifold layer, and further enters the phase change microchannel heat exchange zone of the upper and lower microchannel substrates. The liquid working fluid absorbs heat, boils and vaporizes in the phase change microchannel heat exchange zone to form steam or vapor-liquid two phases, and flows from the middle to both sides along the microchannel, and then flows into the left and right linear collecting grooves of the upper and lower fluid distribution plates, respectively. The left and right wedge-shaped collecting cavities are connected to the left and right linear collecting grooves of the upper and lower fluid distribution plates, respectively, to collect the steam or vapor-liquid mixture from the upper and lower sides, and then discharge it from the liquid outlet after merging inside the intermediate manifold core.

10. The heat dissipation system as described in claim 2, characterized in that, The loop heat pipe is equipped with a backup liquid-driven pump and an automatic regulating valve. Under low heat load, the loop is passively driven by gravity and buoyancy by opening the automatic regulating valve; under high heat load, the working fluid is forcibly driven by closing the automatic regulating valve and opening the backup liquid-driven pump.

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