Spraying enhanced two-phase evaporation type flat plate loop heat pipe evaporator and heat dissipation system

Abstract

The invention discloses a spraying enhanced two-phase evaporation type flat plate loop heat pipe evaporator and a heat dissipation system, and relates to the technical field of heat management of high-heat-flux electronic devices. The evaporator comprises an evaporator base plate, wherein a liquid gathering groove and a steam groove network are arranged on the evaporator base plate; a double-layer capillary core consisting of a fine-hole capillary core and a coarse-hole distribution layer, a liquid baffle with uniformly distributed through holes and an upper cover plate are sequentially covered above the liquid gathering groove and are jointly closed to form a steam cavity, an active spraying device is arranged, condensate is actively sprayed to the area of the liquid gathering groove, and a stable liquid film is formed through the distribution of the double-layer capillary core; steam generated by boiling is guided to a single-end steam confluence area through a steam groove network in a low-resistance mode, and gas-liquid isolation is achieved through a liquid baffle to prevent high-speed steam entrainment. According to the invention, the evaporation area stably maintains the rich liquid nucleate boiling state, the capillary core drying is effectively inhibited, the stable heat dissipation of the extremely high heat flux of over 300W / cm is realized, and the method is suitable for the heat management of high-power chips such as a GPU (Graphic Processing Unit), an AI (Artificial Intelligence) accelerator and the like.

Description

Technical Field

[0001] This invention relates to the field of thermal management technology for high heat flux density electronic devices, specifically to a spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator and heat dissipation system. Background Technology

[0002] With the rapid development of fields such as artificial intelligence, high-performance computing, and data centers, the integration and power density of electronic chips continue to rise. Currently, the power consumption of a single chip has exceeded 2000W, and the local heat flux density exceeds 300W / cm², placing extremely high demands on thermal management systems. Traditional air cooling and single-phase liquid cooling, due to their limited heat dissipation capacity, are no longer sufficient to meet the heat dissipation requirements of such high heat flux density scenarios.

[0003] Two-phase heat dissipation technology utilizes the latent heat of phase change of the working fluid, offering significant advantages in efficient heat transfer. Among these, the loop heat pipe, as a passive two-phase heat transfer device, relies on capillary force generated by the wick to drive the working fluid circulation. It possesses advantages such as no moving parts, long heat transfer distance, and flexible arrangement, and has gradually become a research hotspot for thermal management of high heat flux density devices. However, traditional flat loop heat pipes (LHPs) suffer from the following problems under high heat flux density conditions: (1) Limited capillary force and insufficient liquid reflux can easily lead to the evaporator drying out; (2) The start-up process is unstable and requires precise control of superheat; (3) It is sensitive to gravity. In the vertical or complex specific installation posture of high-density racks in data centers, the backflow resistance increases, which leads to performance limitations and degradation.

[0004] To address the aforementioned issues, some existing technologies have proposed using pump-driven assisted reflux to enhance liquid circulation. However, these approaches primarily focus on external driving methods, neglecting the optimization of the gas-liquid separation and distribution structure within the evaporator. In reality, as the core component of the loop heat pipe, the internal structural design of the evaporator directly determines the uniformity of the liquid film distribution, the stability of evaporation, and the smoothness of vapor discharge. If a coordinated design can be implemented within the evaporator that integrates active spray liquid supply, uniform liquid film formation, and low-resistance vapor extraction, it is expected to significantly improve the system's operational stability and heat dissipation limits under high heat flux densities.

[0005] Therefore, there is an urgent need to design a novel evaporator structure that can maintain stable nucleate boiling under high heat flux density, prevent drying out, and achieve steam discharge with extremely low flow resistance. Summary of the Invention

[0006] The main objective of this invention is to provide a spray-enhanced two-phase evaporative flat-plate loop heat pipe evaporator and heat dissipation system to overcome the problems existing in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator includes an evaporator substrate, a capillary core layer, a baffle plate, an upper cover plate, and a spray device. The outer side of the evaporator substrate is thermally coupled to the heat source, and the inner side is provided with a liquid collection groove corresponding to the high heat flux density area of ​​the heat source. A steam groove network is provided on the evaporator substrate at the position outside the liquid collection groove to guide the steam generated around the liquid collection groove to the steam confluence area. The capillary core layer covers the top of the evaporator substrate, the baffle plate is arranged parallel to the top of the capillary core layer, the upper cover plate covers the top of the baffle plate and is sealed to the outer edge of the evaporator substrate to form a closed steam chamber, and the steam confluence area is located at one end of the steam chamber. The spraying device includes a spray head disposed in the steam chamber, which is used to actively spray condensate into the liquid collection groove.

[0008] Furthermore, the depth of the liquid collecting groove is 0.25-0.50mm, the edge of the liquid collecting groove is set with a slope and rounded corners, and an annular shallow vapor collection groove is set around the slope to serve as a gas-liquid buffer area.

[0009] Furthermore, the steam tank network includes multiple main steam tanks and multiple branch steam tanks. The main steam tanks converge in a fan shape from the periphery of the liquid gathering groove to the steam confluence area. The cross-sectional area of ​​the main steam tanks increases monotonically along the steam flow direction to accommodate the accumulation of steam flow and reduce the flow pressure drop. The branch steam tanks are distributed around the annular shallow steam collection tank, and are used to connect the liquid collection groove and the main steam tank, and to guide the steam generated around the annular shallow steam collection tank into the main steam tank. The steam flows along the main steam tank with low resistance to the steam confluence area.

[0010] Furthermore, the width of the main steam tank is 0.1-0.5 mm and the depth is 0.30-0.55 mm.

[0011] Furthermore, the capillary core layer includes a fine-pore capillary core layer and a coarse-pore distribution layer arranged sequentially from bottom to top; The thickness of the fine-pore capillary core layer in the region corresponding to the liquid gathering groove is less than the thickness of the outer region. The pore size of the fine-pore capillary core layer is 10-30 μm and the thickness is 0.3-0.8 mm. The pore size of the coarse-pore distribution layer is 50-100 μm and the thickness is 0.5-2 mm.

[0012] Furthermore, the baffle plate covers the entire evaporation area to isolate the vapor chamber above it from the liquid area below it. Its thickness is 0.2-0.4 mm, and its surface is evenly distributed with through holes. The opening rate of the surface through holes is 20%-40%.

[0013] Furthermore, the height of the steam chamber in the evaporation area is 1.2-1.8 mm, and it is locally raised to 2.5-3.0 mm in the steam confluence area, thereby forming a single-end steam confluence chamber structure.

[0014] Furthermore, the total opening area of ​​the spray head is configured to make it the main throttling element for controlling the spray flow rate, and the spray flow rate is configured to be 1.2-3 times the theoretical lower limit flow rate, so as to maintain the liquid-rich nucleus boiling state in the evaporation zone and suppress capillary drying.

[0015] Furthermore, the spray head has a pressure drop of 10-40 kPa at the target flow rate and is provided with an array of spray holes, the number of which is 15-25.

[0016] A spray-enhanced two-phase evaporative flat-plate loop heat pipe cooling system includes an evaporator, a condenser, a steam pipe, and a return pipe. The steam pipe connects the evaporator and the condenser, and the return pipe connects the condenser and the spray device. The spray device is driven by a liquid-driven magnetic pump located on the return liquid path, and a magnetic pump fluid drive pipe is connected to the liquid-driven magnetic pump.

[0017] Compared with the prior art, the present invention has the following beneficial effects: High heat flux density withstand capability: The optimized evaporator structure combined with active spraying can withstand high heat flux densities of over 300W / cm². Stable nucleate boiling: The liquid-rich state and the double-layer capillary wick ensure a stable evaporation interface and prevent drying out; Low-resistance steam discharge: The tree-like steam trough network and single-end steam collection chamber structure significantly reduce steam pressure drop and minimize temperature penalty; Uniform liquid supply: The coarse-pore distribution layer enables rapid lateral distribution of liquid; Gas-liquid isolation: The baffle plate effectively prevents vapor from entraining liquid; High adaptability to working fluids: It can be adapted to a variety of insulating and environmentally friendly dielectric fluorinated liquids; Redundancy and reliability: When the spray pump is shut down or fails, the system can still operate passively by capillary force, improving the security of data center servers. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the layout of the evaporator substrate and main components of the present invention.

[0019] Figure 2This is a schematic diagram of the evaporator substrate structure of the present invention.

[0020] Figure 3 This is a side view of the heat dissipation structure of the condenser plate and sandwich condenser of the present invention, which uses a dual water-cooled plate.

[0021] Figure 4 This is a top view of the heat dissipation system of the present invention.

[0022] Figure 5 This is a side view of the heat dissipation system of the present invention.

[0023] Explanation of reference numerals in the attached drawings: 001 Heat source, 100 Evaporator substrate, 101 Thermal interface, 102 Liquid collection groove, 103 Fine-pore capillary core layer, 104 Coarse-pore distribution layer, 105 Main steam tank, 106 Baffle plate, 107 Steam convergence zone, 108 Condensate return pipe, 109 Top cover plate, 110 Steam chamber, 111 Spray head, 112 Branch steam tank, 113 Annular shallow steam collection tank, 114 Slope, 200 Condenser, 201 Lower water-cooled microchannel of condenser bottom plate, 202 Upper water-cooled microchannel of condenser top plate, 20 3. Steam pipe, 210. Condensate storage tank, 300. Lower water-cooled plate, 301. Lower water-cooled manifold, 302. Lower water-cooled inlet / outlet pipe, 400. Upper water-cooled plate, 401. Upper water-cooled manifold, 501. Cold water plate inlet, 502. Cold water plate inlet manifold, 503. Cold water plate outlet, 504. Cold water plate outlet manifold, 505. Upper cold water plate inlet pipe, 506. Upper cold water plate outlet pipe, 507. Upper water plate inlet interface, 508. Upper water plate outlet interface, 800. Liquid-driven magnetic pump, 900. Magnetic pump fluid drive pipe. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Example 1

[0026] Combination Figures 1 to 2This embodiment provides a spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator, including an evaporator substrate 100, a capillary core layer, a baffle plate 106, an upper cover plate 109, and a spray device. The outer side of the evaporator substrate 100 is thermally coupled to a heat source 001, and a liquid collection groove 102 is provided on the inner side corresponding to the high heat flux density region of the heat source 001. A vapor channel network is provided on the evaporator substrate 100 around the liquid collection groove 102 to collect vapors generated around the liquid collection groove 102. The vapor-guiding vapor confluence area 107; a capillary wick layer covers the top of the evaporator substrate 100, a baffle plate 106 is arranged parallel above the capillary wick layer, an upper cover plate 109 covers the baffle plate 106 and is sealed to the outer edge of the evaporator substrate 100 to form a closed vapor chamber 110, and the vapor confluence area 107 is located at one end of the vapor chamber 110; the spray device includes a spray head 111 disposed in the vapor chamber 110, and the spray head 111 is used to actively spray condensate into the liquid collection groove 102.

[0027] This scheme utilizes an active liquid supply system via a spray device, combined with an optimized internal structure of the evaporator (including a liquid collection groove 102, a steam tank network, a double-layer capillary core, and a baffle plate 106), to achieve stable nucleate boiling under high heat flux density and low-resistance steam discharge.

[0028] Specifically, the liquid collecting groove 102 is used to receive the spray liquid and provide transient buffering, while guiding steam away from the vicinity of the capillary zone. The liquid collecting groove 102 is set to correspond to the high-density heat source 001, and its planar size is slightly larger than that of the heat source 001. The steam tank network adopts a tree-like structure of main trunk + branch grooves to achieve rapid steam collection and low pressure drop guidance. The fine-pore capillary core layer 103 in the double-layer capillary core can maintain the stability of the evaporation interface, and the coarse-pore distribution layer 104 can realize the lateral distribution of liquid. The horizontal baffle 106 can isolate the high-speed steam zone and the low-speed liquid zone to prevent high-speed steam from entraining liquid. The single-end steam manifold can reduce the local resistance loss at the end and stabilize the steam output. The spray flow rate is controlled so that the spray flow rate is greater than 1.2-3 times the theoretical lower limit of the complete evaporation flow rate to maintain the liquid-rich nucleus boiling state.

[0029] During operation, the spray head 111 actively sprays the condensate into the liquid collection groove 102. The liquid in the groove is drawn into the fine-pore capillary core through capillary action, forming a stable liquid film on the surface of the core layer. The heat generated by the heat source 001 is conducted to the liquid film through the evaporator substrate 100, driving the working fluid to boil and evaporate. The generated steam is quickly discharged through the steam tank network and flows along the low-resistance steam tank to the steam collection area 107. The baffle plate 106 prevents the high-speed steam from entraining the liquid in the capillary core. After the steam is collected in the steam collection area 107, it enters the condenser 200 through the steam outlet for condensation. The condensate is then supplied to the spray device again through the condensate return pipe 108, completing the cycle.

[0030] In this embodiment, the evaporator substrate 100 is thermally coupled to the heat source via a liquid alloy thermal medium, preferably a dielectric fluorinated liquid with a boiling point selectable within the range of 50–100°C, exhibiting high dielectric strength, chemical inertness, and good thermophysical properties. The evaporator substrate 100 is a rectangular flat plate structure, the size of which can be determined according to the size of the heat source and application requirements, preferably larger than the high-density chip, and the substrate material is a high thermal conductivity material.

[0031] In this embodiment, the liquid collecting groove 102 is located at the center of the upper surface of the evaporator substrate 100, with a depth of 0.25-0.50 mm. The edge of the liquid collecting groove 102 is provided with a slope 114 and rounded corners. An annular shallow vapor collecting groove 113 is provided around the slope 114 to serve as a gas-liquid buffer area. The bottom surface of the liquid collecting groove 102 can be slightly roughened to enhance the consistency of wetting and nucleation.

[0032] In this embodiment, the steam tank network includes multiple main steam tanks 105 and multiple branch steam tanks 112. The main steam tanks 105 converge in a fan shape from the periphery of the liquid collection groove 102 to the steam confluence area 107. The cross-sectional area of ​​the main steam tanks 105 increases monotonically along the steam flow direction to accommodate the accumulation of steam flow and reduce the flow pressure drop. Among them, the branch steam tank 112 is distributed around the annular shallow steam collecting tank 113, which is used to connect the liquid collecting groove 102 and the main steam tank 105, and to guide the steam generated around the annular shallow steam collecting tank 113 into the main steam tank 105 nearby, thereby reducing the travel distance of the steam in the capillary layer. The main steam tank gradually widens as the flow rate increases, and the steam flows along the gradually widening main steam tank 105 towards the steam confluence area 107 with low resistance.

[0033] Specifically, the width of the main steam tank 105 is 0.1-0.5mm and the depth is 0.30-0.55mm.

[0034] In this embodiment, the capillary wick layer covers the entire evaporator substrate 100 area and includes a fine-pore capillary wick layer 103 and a coarse-pore distribution layer 104 arranged sequentially from bottom to top. The thickness of the fine-pore capillary wick layer 103 can be adjusted according to the region. The thickness in the region corresponding to the liquid gathering groove 102 is less than the thickness in the outer region. That is, in the core region of the liquid gathering groove 102, the thickness can gradually increase outward to enhance the lateral spreading ability of the liquid. The function of the coarse-pore distribution layer 104 is to quickly distribute the liquid sprayed into the liquid gathering groove 102 to the entire evaporation area and to act as a liquid buffer layer to cope with transient power fluctuations.

[0035] Specifically, the fine-pore capillary core layer 103 has a pore size of 10-30 μm and a thickness of 0.3-0.8 mm, while the coarse-pore distribution layer has a pore size of 50-100 μm and a thickness of 0.5-2 mm.

[0036] In this embodiment, the baffle plate 106 is parallel to the capillary core layer and is used to isolate the vapor chamber 110 above it from the liquid area below it. Its thickness is 0.2-0.4 mm, and its surface is evenly distributed with through holes. The porosity of the surface through holes is 20%-40%.

[0037] Using this design, the baffle plate 106 can isolate the low-speed liquid zone below and the high-speed vapor zone above, preventing the vapor from carrying away the liquid in the capillary wick. The vapor passes through the through-hole of the baffle plate 106 into the vapor chamber 110, while the liquid is blocked and retained below by the baffle plate, achieving gas-liquid separation. Preferably, the baffle plate covers the entire evaporation area (full coverage) to ensure the gas-liquid separation effect.

[0038] In this embodiment, the height design of the steam chamber 110 needs to balance pressure drop and response speed: too small a height will result in excessive pressure drop and increased temperature penalty; too large a height will result in excessively low steam flow rate and slow response. Specifically, the height in the evaporation area is 1.2-1.8 mm, and it is locally raised to 2.5-3.0 mm in the steam confluence area 107, thereby forming a single-end steam confluence chamber structure.

[0039] In this design, a steam manifold 107 is set at one end of the evaporator. The ends of all main steam tanks 105 directly flow into the steam manifold 107, with smooth transitions to avoid sharp bends or right angles. As a single-end steam collection chamber, the steam manifold can significantly reduce local resistance losses at the end.

[0040] In this embodiment, the spray head 111 is embedded in or passes through the baffle plate 106. The total opening area of ​​the spray head 111 is configured to make it the main throttling element for controlling the spray flow rate, ensuring uniform spraying. The pressure drop of the spray head at the target flow rate is 10-40 kPa, and it is provided with 15-25 spray holes arranged in an array.

[0041] Using this method, for high-density heat dissipation, the spray flow rate is controlled at 1.2-3 times the theoretical lower limit of complete evaporation, which can ensure that the evaporation zone is always in a liquid-rich state, maintain efficient nucleation boiling and prevent drying.

[0042] In this embodiment, for chips with a power output higher than 2000W in a ground-based high-density server, the heat source size is 25×25mm-50×50mm. The following parameters are used: evaporator substrate size 45-65×50×65mm, thickness 1-3mm; liquid collection groove 102 larger than the heat source size, depth 0.1-0.5mm; number of main steam channels 105 6-10, width 0.1-0.5mm, depth 0.1-0.4mm; number of branch steam channels 112 8-20, width 0.3mm-0.5mm, depth 0.1-0.3mm; fine pore capillary core area thickness 0.2-0.7mm, pore diameter 15-35μm; coarse pore distribution layer thickness 0.5-2mm, pore diameter 60-100μm; baffle plate thickness 0.2-0.5mm, opening rate 20%-50%; steam chamber height 1-2.5mm, steam confluence zone height 1-3.5mm; spray orifice plate 15-25 holes, target flow rate 1-3L / min.

[0043] Example 2

[0044] Combination Figures 3 to 5 This embodiment provides a spray-enhanced two-phase evaporative flat-plate loop heat pipe cooling system, including the evaporator, condenser 200, steam pipe 203, and return pipe 108 of Embodiment 1 above. The steam pipe 203 connects the evaporator and the condenser 200, and the return pipe 108 connects the condenser 200 and the spray device. The spray device is driven by a liquid-driven magnetic pump 800 located on the return liquid path, and a magnetic pump fluid drive pipe 900 is connected to the liquid-driven magnetic pump 800. The steam chamber 110 is connected to the condenser 200 through the steam pipe 203. After being collected in the condensate storage tank 210, the condensate is connected to the spray drive pump through the return pipe 108 and pushed to the spray head 111.

[0045] The active fluid supply is powered by a magnetically coupled isolated pump, which includes an external magnetic rotor, an isolation wall, and an internal impeller structure, with no mechanical shaft penetrating the isolation wall. In one embodiment, the external magnetic rotor is driven by an electric motor; in another embodiment, the external magnetic rotor is driven by the fluid kinetic energy of the main cooling circuit.

[0046] In this embodiment, the condenser 200 adopts a sandwich-style double-layer water-cooled plate cooling and condensation structure, including a lower water-cooled plate 300 and an upper water-cooled plate 400. The upper and lower water-cooled plates and the condenser 200 are coupled with a common wall design. The bottom plate of the condenser 200 and the top plate of the lower water-cooled plate share a common wall, and there is a lower water-cooled microchannel 201 on one side of the water-cooled plate. The top plate of the condenser and the bottom plate of the upper water-cooled plate share a common wall, and there is an upper water-cooled microchannel 202 on one side of the water-cooled plate, thereby minimizing thermal resistance. The lower water-cooled plate 300 has a lower water-cooled manifold 301 inside, which is connected to a liquid-cooled distributor through a lower water-cooled inlet / outlet pipe 302. The upper water-cooled plate 400 has an upper water-cooled manifold 401 inside.

[0047] In this embodiment, the system also includes a liquid-cooled distributor for distributing and collecting fluid, and the liquid-cooled distributor is externally connected to a liquid-cooled interface.

[0048] Working principle: The spray head 111 of the spray device actively sprays the condensate into the liquid collection groove 102. The liquid in the groove is drawn into the microporous capillary core layer 103 through capillary action, forming a stable liquid film on the surface of the core layer. The heat generated by the heat source 001 is conducted to the liquid film through the evaporator substrate 100, driving the working fluid to boil and evaporate.

[0049] The generated steam enters the main steam tank 105 through the branch steam tank 112, and flows along the main steam tank at low resistance to the steam confluence area 107. The baffle plate 106 prevents the high-speed steam from entraining the liquid in the coarse-pore distribution layer 104.

[0050] Steam is gathered in steam manifold 107 and then enters condenser 200 through steam pipe 203 for condensation. The condensate enters condensate storage tank 210 and is then fed back to the spray device through condensate return pipe 108 by drive pump, completing the cycle.

[0051] Example 3

[0052] This embodiment provides a two-phase spray evaporation heat dissipation method for high heat flux density chips, based on the evaporator described above, and includes the following steps: (a) The condensate is actively and uniformly sprayed onto the high heat flux density liquid collection area of ​​the evaporator substrate 100 by a spraying device; (b) A stable liquid film distribution is formed on the heated surface by the capillary attraction of the double-layered porous capillary wick; (c) While maintaining a liquid-rich state, the working fluid absorbs heat from the heat source to undergo stable nucleate boiling; (d) The steam generated by boiling is led out to the single-end steam collection area with low resistance through the tree-like steam tank network, and the steam is prevented from entraining liquid by the baffle plate during the process; (e) Dynamic control maintains the spray flow rate at 1.2–3 times the theoretical lower limit of complete evaporation.

[0053] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator, characterized in that, It includes an evaporator substrate (100), a capillary core layer, a baffle plate (106), an upper cover plate (109), and a spray device; The outer side of the evaporator substrate (100) is thermally coupled to the heat source (001), and the inner side is provided with a liquid collection groove (102) corresponding to the high heat flux density area of ​​the heat source (001). A steam channel network is provided on the evaporator substrate (100) at the position outside the liquid collection groove (102) to guide the steam generated around the liquid collection groove (102) to the steam confluence area (107). The capillary core layer covers the top of the evaporator substrate (100), the baffle plate (106) is arranged parallel to the top of the capillary core layer, the upper cover plate (109) covers the top of the baffle plate (106) and is sealed to the outer edge of the evaporator substrate (100) to form a closed steam chamber (110), and the steam confluence area (107) is located at one end of the steam chamber (110). The spraying device includes a spray head (111) disposed in the steam chamber (110), the spray head (111) being used to actively spray condensate into the liquid collection groove (102).

2. The spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 1, characterized in that, The depth of the liquid collection groove (102) is 0.25-0.50mm. The edge of the liquid collection groove (102) is set with a slope (114) and rounded corners. An annular shallow vapor collection groove (113) is set around the slope (114) to serve as a gas-liquid buffer area.

3. The spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 2, characterized in that, The steam tank network includes multiple main steam tanks (105) and multiple branch steam tanks (112). The main steam tanks (105) converge in a fan shape from the periphery of the liquid gathering groove (102) to the steam confluence area (107). The cross-sectional area of ​​the main steam tanks (105) increases monotonically along the steam flow direction to accommodate the accumulation of steam flow and reduce the flow pressure drop. The branch steam tank (112) is distributed around the annular shallow steam collection tank (113) to connect the liquid collection groove (102) and the main steam tank (105), and to introduce the steam generated around the annular shallow steam collection tank (113) into the main steam tank (105) nearby. The steam flows along the main steam tank (105) to the steam confluence area (107) with low resistance.

4. The spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 3, characterized in that, The main steam tank (105) has a width of 0.1-0.5 mm and a depth of 0.30-0.55 mm.

5. The spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 1, characterized in that, The capillary core layer includes a fine-pore capillary core layer (103) and a coarse-pore distribution layer (104) arranged sequentially from bottom to top. The thickness of the fine-pore capillary core layer (103) in the region corresponding to the liquid gathering groove (102) is less than the thickness of the outer region. The pore size of the fine-pore capillary core layer (103) is 10-30 μm and the thickness is 0.3-0.8 mm. The pore size of the coarse-pore distribution layer (104) is 50-100 μm and the thickness is 0.5-2 mm.

6. The spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 1, characterized in that, The baffle plate (106) covers the entire evaporation area and is used to isolate the vapor chamber (110) above it from the liquid area below it. Its thickness is 0.2-0.4 mm and its surface is evenly distributed with through holes. The opening rate of the surface through holes is 20%-40%.

7. The spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 1, characterized in that, The height of the steam chamber (110) in the evaporation area is 1.2-1.8 mm, and it is locally raised to 2.5-3.0 mm in the steam confluence area (107), thereby forming a single-end steam confluence chamber structure.

8. The spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 1, characterized in that, The total opening area of ​​the spray head (111) is configured to make it the main throttling element for controlling the spray flow rate, and the spray flow rate is configured to be 1.2-3 times the theoretical lower limit flow rate, so as to maintain the liquid-rich core boiling state in the evaporation zone and suppress the drying of the capillary wick.

9. A spray-enhanced two-phase evaporation flat-plate loop heat pipe evaporator as described in claim 8, characterized in that, The spray head has a pressure drop of 10-40 kPa at the target flow rate and is provided with an array of spray holes, the number of which is 15-25.

10. A spray-enhanced two-phase evaporative flat-plate loop heat pipe cooling system, comprising the evaporator according to any one of claims 1-9, characterized in that, It also includes a condenser (200), a steam pipe (203), and a return pipe (108). The steam pipe (203) is used to connect the evaporator and the condenser (200). The return pipe (108) is used to connect the condenser (200) and the spray device. The spray device is driven by a liquid-driven magnetic pump (800) located on the return liquid path. The liquid-driven magnetic pump (800) is connected to a magnetic pump fluid drive pipe (900).

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