3D vapor chamber based on Bernoulli's principle

Abstract

This invention discloses a 3D vapor chamber based on Bernoulli's principle, comprising a main body with a steam chamber divided into a core area and a non-core area. A connecting unit is provided on the main body, and a steam channel is provided within the connecting unit. The two ends of the steam channel connect the core area and the non-core area of ​​the steam chamber, respectively. The end of the steam channel corresponding to the core area is venturi-shaped along the mainstream steam direction. This invention sets a connecting unit between adjacent steam channels, utilizing a gradually narrowing-expanding cross-section to generate a local low-pressure area during the lateral migration of steam, creating a "suction / guidance" effect on the mainstream steam, shortening the effective flow path, significantly reducing the total steam pressure drop, and reducing the total thermal resistance of the 3D vapor chamber by more than 20%, while improving in-plane temperature uniformity. It is suitable for high heat flux scenarios such as communication equipment and AI computing terminals.

Description

Technical Field

[0001] This utility model relates to the field of radiator technology, and in particular to a 3D vapor chamber based on Bernoulli's principle. Background Technology

[0002] Existing 3D vapor chambers generally employ independent vertical vapor channels. In high power density scenarios: (1) The single path leads to high steam velocity, significant friction and local resistance along the path, and increased steam pressure drop ΔP_v; (2) When the heat source is unevenly distributed, local high pressure zones and flow dead zones are likely to occur, resulting in heat accumulation and poor temperature uniformity; (3) ΔP_v is positively correlated with the total thermal resistance R_total, which becomes the bottleneck restricting the heat dissipation performance of the 3D vapor chamber.

[0003] In existing technologies, most methods reduce resistance by increasing the thickness of the steam chamber, adding micropillars, or optimizing the liquid suction core. However, these methods often conflict with space constraints or weight requirements and do not address the pressure drop problem from the perspective of "actively controlling steam dynamics". Utility Model Content

[0004] The technical problem to be solved by this utility model embodiment is to provide a 3D heat spreader based on Bernoulli's principle, so as to improve the in-plane temperature uniformity and heat dissipation efficiency without increasing the overall thickness or sacrificing mechanical strength.

[0005] To solve the above-mentioned technical problems, this utility model proposes a 3D heat spreader based on Bernoulli's principle, including a body, a steam chamber inside the body, the steam chamber being divided into a core area and a non-core area, a connecting unit on the body, a steam channel inside the connecting unit, the two ends of the steam channel connecting the core area and the non-core area of ​​the steam chamber respectively, and the steam channel being venturi-shaped at one end corresponding to the core area along the main steam flow direction.

[0006] Furthermore, the steam passage is divided into a constriction section, a proximal section, a middle section, and a distal section along the main steam flow direction. The distal section connects to the non-core area of ​​the steam chamber, and the inner walls of the middle and distal sections are provided with a first capillary structure.

[0007] Furthermore, the ratio of the cross-sectional area at the narrowest point of the constricted section to the cross-sectional area of ​​the proximal section is 0.25:0.50.

[0008] Furthermore, the length of the constricted section is ≤ 1.5 mm.

[0009] Furthermore, the narrowing angle of the narrowing section ranges from 5° to 15°.

[0010] Furthermore, the connecting unit is a U-shaped heat pipe.

[0011] Furthermore, a flow-limiting capillary structure is installed at the port of the far-end section connecting to the non-core area of ​​the steam chamber.

[0012] Furthermore, a second capillary structure is provided at the bottom of the steam chamber, and the flow-limiting capillary structure overlaps with the second capillary structure.

[0013] Furthermore, the longitudinal spacing p of the connected units satisfies p = λ / 2 (± 5%), where λ is the half wavelength of the steam pressure pulsation.

[0014] Furthermore, the cross-sectional area at the steam channel port corresponding to the core area of ​​the steam chamber is larger than the cross-sectional area at the port where the steam channel connects to the core area.

[0015] The beneficial effects of this utility model are as follows: 1. Thermal resistance: Under a heat source of ≥ 50 W, simulations show that the total thermal resistance R_total decreases by approximately 20%; 2. Temperature uniformity: The temperature difference at the condenser end face decreases by more than 10%; 3. Process compatibility: Only requires adding U-shaped heat pipe interconnects to the traditional 3D vapor chamber process, with a cost increase of less than 5%. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of a 3D temperature distribution plate based on Bernoulli's principle according to an embodiment of this utility model.

[0017] Figure 2 This is a top view of a 3D heat spreader based on Bernoulli's principle according to an embodiment of this utility model.

[0018] Figure 3 yes Figure 2 Sectional view at point BB.

[0019] Figure 4 yes Figure 3 Enlarged view of point C in the middle.

[0020] Figure 5 yes Figure 3 Enlarged view of point D in the middle.

[0021] Figure 6 This is a partial structural diagram of a 3D heat spreader based on Bernoulli's principle according to an embodiment of this utility model.

[0022] Figure 7 This is a three-dimensional structural diagram of the connecting unit according to an embodiment of the present utility model.

[0023] Figure 8 is a schematic diagram of the test results of an embodiment of the present invention. Figure 8(a) and Figure 8(b) are schematic diagrams of temperature distribution data of the existing 3D heat spreader and the 3D heat spreader of the present invention, respectively. Figure 8(c) and Figure 8(d) are schematic diagrams of pressure distribution data of the existing 3D heat spreader and the 3D heat spreader of the present invention, respectively.

[0024] Explanation of icon numbers 10. Body, 11. Core area, 12. Non-core area, 13. Flow-limiting capillary structure, 14. Second capillary structure, 20. Connecting unit, 21. Narrowing section, 22. Proximal section, 23. Middle section, 24. Distal section, 25. First capillary structure. Detailed Implementation

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] In this embodiment of the invention, directional indicators (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of the components in a specific posture (as shown in the attached figure). If the specific posture changes, the directional indicators will also change accordingly.

[0027] Furthermore, in this utility model, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0028] Please refer to Figures 1 to 7 The 3D vapor chamber based on Bernoulli's principle according to this embodiment of the invention includes a body. The body contains a vapor chamber, which is divided into a core area and a non-core area. A working fluid is contained within the vapor chamber. The body typically consists of an upper cover and a lower cover. Type I heat pipes are typically mounted on the body. This part is common knowledge in the art and will not be described in detail here.

[0029] The main body has one or more connecting units. Each connecting unit is hollow, forming a steam channel. The two ends of the steam channel connect to the core area and the non-core area of ​​the steam chamber, respectively. The axial cross-section of the steam channel at the end corresponding to the core area is Venturi-shaped along the direction of the main steam flow. The main steam flow direction is from the core area to the non-core area. This invention, by setting a Venturi-shaped connecting port, utilizes the Bernoulli effect to create a local low-pressure area to guide the lateral migration of steam and reduce the total pressure drop.

[0030] In one implementation, the connecting unit and steam passage are sequentially divided into a constricted section, a proximal section, a middle section, and a distal section along the main steam flow direction. The distal section connects to the non-core area of ​​the steam chamber. The inner walls of the middle and distal sections are provided with first capillary structures, which overlap each other. Preferably, the first capillary structures are arranged in rings around the inner walls of the middle and distal sections. The constricted section of this invention can increase the flow rate of steam entering the proximal section. The first capillary structure in the middle section can enhance the directionality of steam within the middle section, allowing steam to enter the distal section more smoothly.

[0031] As one implementation, the ratio η of the cross-sectional area at the narrowest point of the constriction (i.e., the Venturi throat A_throat) to the cross-sectional area of ​​the proximal segment (i.e., the Venturi throat outlet A_channel) is 0.25:0.50, which yields the best results. η = A_throat / A_channel ∈ [0.25, 0.50].

[0032] According to Bernoulli's equation P + ½ρv² = const, throat acceleration leads to a decrease in static pressure ΔP_Bernoulli ≈½ρ(v_throat² – v_channel²); This negative pressure, acting as an additional driving force, can reduce the overall pressure drop ΔP_total = ΔP_friction – ΔP_Bernoulli, thus achieving R_vapor↓ → R_total↓.

[0033] As one implementation method, the length of the constricted section L_t ≤ 1.5 mm. If it is too short, it is difficult to process and the lifting effect is not obvious; if it is too long, it also affects the lifting effect.

[0034] In one implementation, the narrowing angle φ of the narrowing section ranges from 5° to 15°.

[0035] In one implementation, the connecting unit is a U-shaped heat pipe. Other similar U-shaped structures may also be used in specific implementations.

[0036] In one implementation, a flow-limiting capillary structure is provided at the port of the distal section connecting to the non-core area of ​​the steam chamber. The flow-limiting capillary structure blocks part of the outlet end of the distal section, thus acting as a barrier to allow the steam flowing into the non-core area to flow back, while not affecting the flow of liquid in the steam channel into the non-core area of ​​the steam chamber.

[0037] In one implementation, a second capillary structure is provided on the bottom side of the steam chamber (i.e., the side facing the heat source). The flow-limiting capillary structure overlaps with the second capillary structure, allowing the liquid in the steam channel to flow rapidly towards the side of the steam chamber facing the heat source. In a specific implementation, the flow-limiting capillary structure can be made by sintering the same copper powder as the second capillary structure together with it.

[0038] As one implementation, the longitudinal spacing p of the connecting units satisfies p ≈ λ / 2 (equal to or approximately equal to), preferably p = λ / 2 (± 5%), where λ is the half wavelength of the steam pressure pulsation, ensuring phase coupling between the low-pressure region and the high-pressure region.

[0039] As one implementation method, the cross-sectional area at the steam channel port corresponding to the core area of ​​the steam chamber is larger than the cross-sectional area at the port connecting the steam channel to the core area, further enhancing the "suction / drainage" effect on the mainstream steam.

[0040] The preparation method of this utility model can adopt conventional preparation methods, and the manufacturing method includes the following steps: a) The connecting opening is processed on a metal substrate (copper, aluminum or its alloy) by laser cutting and stamping or chemical etching to form the top cover; b) The lower cover is formed by die casting, stamping, or machining; c) Encapsulate the top and bottom covers by diffusion solder atomic layer deposition (ALD) or other metal soldering; d) Fit the U-shaped heat pipe, type I, and other shapes into the corresponding holes in the top cover, and achieve the overlap with the top and bottom covers by brazing; e) Inject the working fluid (pure water or dielectric liquid), evacuate, and then seal.

[0041] This invention sets up a connecting unit between adjacent steam channels, and uses the gradually narrowing-expanding cross section to generate a local low-pressure zone when the steam migrates laterally, forming a "suction / guidance" effect on the mainstream steam, shortening the effective flow path, significantly reducing the total steam pressure drop, reducing the total thermal resistance of the 3D heat spreader by more than 20%, and improving the in-plane temperature uniformity. It is suitable for high heat flux scenarios such as communication equipment and AI computing terminals.

[0042] Figure 8 shows a comparison of the simulated pressure drop and thermal resistance data of the 3D vapor chamber of this invention with existing 3D vapor chambers. The test conditions were: heat source power 500W, air temperature 28 degrees Celsius, and air flow rate 10 CFM. The comparison results are shown in Table 1.

[0043]

[0044] Example 1: Substrate material: TU1 oxygen-free copper; U-shaped passage: width 6mm, height > 30mm, U-shaped spacing > 20mm; Constriction angle: η = 0.30, φ = 15°, p = 20 mm; Working fluid: pure water, filling rate 105%; Test results: R_total = 0.03 K / W, temperature uniformity improved by 35%.

[0045] Example 2 (Communication Base Station Power Amplifier): When the 3DVC described in Example 1 is bonded to a 100 W LDMOS power amplifier, the case temperature decreases by 5.3 °C and the MTBF increases by 15%.

[0046] Example 3 (AI Computing Card GPU Module): Replacing traditional heatsinks in AI accelerator cards reduces junction temperature by 6.1 °C, fan speed by 12%, and noise by 2.1 dB(A) when the GPU's continuous power consumption is 300 W.

[0047] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 3D vapor chamber based on Bernoulli's principle, comprising a body, wherein a vapor chamber is provided within the body, the vapor chamber being divided into a core region and a non-core region, characterized in that, The main body is provided with a connecting unit, and a steam channel is provided in the connecting unit. The two ends of the steam channel are respectively connected to the core area and non-core area of ​​the steam chamber. The end of the steam channel corresponding to the core area is venturi-shaped along the main steam direction.

2. The 3D heat spreader based on Bernoulli's principle as described in claim 1, characterized in that, The steam passage is divided into a constriction section, a proximal section, a middle section, and a distal section along the main steam flow direction. The distal section connects to the non-core area of ​​the steam chamber, and the inner walls of the middle and distal sections are provided with a first capillary structure.

3. The 3D heat spreader based on Bernoulli's principle as described in claim 2, characterized in that, The ratio of the cross-sectional area at the narrowest point of the constricted section to the cross-sectional area of ​​the proximal section is 0.25:0.

50.

4. The 3D heat spreader based on Bernoulli's principle as described in claim 2, characterized in that, The length of the constricted section is ≤ 1.5mm.

5. The 3D heat spreader based on Bernoulli's principle as described in claim 2, characterized in that, The narrowing angle of the narrowing section ranges from 5° to 15°.

6. The 3D heat spreader based on Bernoulli's principle as described in claim 2, characterized in that, The connecting unit is a U-shaped heat pipe.

7. The 3D heat spreader based on Bernoulli's principle as described in claim 2, characterized in that, A flow-limiting capillary structure is installed at the port of the far end section connecting to the non-core area of ​​the steam chamber.

8. The 3D heat spreader based on Bernoulli's principle as described in claim 7, characterized in that, A second capillary structure is provided at the bottom of the steam chamber, and the flow-limiting capillary structure overlaps with the second capillary structure.

9. The 3D heat spreader based on Bernoulli's principle as described in claim 1, characterized in that, The longitudinal spacing p of the connected units satisfies p = λ / 2 (± 5%), where λ is the half wavelength of the steam pressure pulsation.

10. The 3D heat spreader based on Bernoulli's principle as described in claim 1, characterized in that, The cross-sectional area at the steam channel port corresponding to the core area of ​​the steam chamber is larger than the cross-sectional area at the port where the steam channel connects to the core area.

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