Novel mechanical-pump-free flow boiling radiator

Abstract

The invention discloses a novel mechanical-pump-free flow boiling radiator, and relates to the technical field of heat dissipation of electronic equipment. By means of the injection and pressurization effects of the vapor-liquid two-phase injection booster, the supercooled liquid with the mass being dozens of times or even hundreds of times is effectively pumped into the boiling pool, the efficient flowing and boiling heat dissipation effect is formed in the heat dissipation core area, and therefore effective heat dissipation of the high-heat-flux electronic device is achieved. The radiator comprises an evaporator, a vapor-liquid two-phase injection boosting device, a first condenser, a boiling pool and a second condenser, a steam outlet of the evaporator is communicated with a gas-phase inlet of the vapor-liquid two-phase injection boosting device, and a liquid-phase outlet of the evaporator is communicated with an inlet of the boiling pool; an outlet of the boiling pool is communicated with an inlet of the second condenser, and an outlet of the second condenser is communicated with a liquid phase inlet of the vapor-liquid two-phase injection boosting device; an outlet of the vapor-liquid two-phase injection boosting device is communicated with an inlet of the first condenser, and an outlet of the first condenser is communicated with an inlet of the evaporator.

Description

Technical Field

[0001] This application relates to the technical field of heat dissipation for electronic devices, and particularly to a novel mechanical-pump-free flow boiling radiator. Background Art

[0002] With the rapid development of technology, the integration and performance of electronic devices have been continuously improved, resulting in increasingly prominent heat dissipation problems with high heat flux densities up to the 100 W / cm 2 level. This poses a major challenge to the performance, safety, and reliability of electronic devices. Although the mechanical-pump-driven flow boiling heat dissipation loop can operate effectively at relatively high heat flux densities, it contains high-speed rotating moving parts and liquid storage devices, significantly reducing the reliability of the system and increasing the weight and volume of the device, which limits its application in certain scenarios.

[0003] The mechanical-pump-driven heat dissipation system requires an external power source to maintain fluid circulation. In addition, the risk of wear and failure of the moving parts increases, affecting the stability of its operation. In some high-demand application scenarios, such as space exploration or military equipment, the reliability of the device is crucial for ensuring the success of the mission. Therefore, it is particularly important to seek a heat dissipation solution without an external power source and without moving parts.

[0004] Some existing mechanical-pump-free flow boiling heat dissipation loops have the following defects: First, their operation depends on the support of gravity, which limits their applicability in specific application scenarios; second, when the heat load increases, the liquid supply of the boiling pool may not be able to keep up in time, resulting in dry burning. Summary of the Invention

[0005] The embodiments of this application provide a novel mechanical-pump-free flow boiling radiator, which utilizes the entrainment and boosting effects of a vapor-liquid two-phase ejector booster to effectively suck dozens or even hundreds of times the mass of subcooled liquid into the boiling pool, forming an efficient heat dissipation effect of flow boiling in the heat dissipation core area, thereby achieving effective heat dissipation for high heat flux density electronic devices.

[0006] To achieve the above object, the embodiments of this application provide a novel mechanical-pump-free flow boiling radiator, including an evaporator, a vapor-liquid two-phase ejector booster, a first condenser, a boiling pool, and a second condenser; the steam outlet of the evaporator is connected to the gas-phase inlet of the vapor-liquid two-phase ejector booster, and the liquid-phase outlet of the evaporator is connected to the inlet of the boiling pool; the outlet of the boiling pool is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the liquid-phase inlet of the vapor-liquid two-phase ejector booster; the outlet of the vapor-liquid two-phase ejector booster is connected to the inlet of the first condenser, and the outlet of the first condenser is connected to the inlet of the evaporator.

[0007] Further, the vapor-liquid two-phase ejector boosting device includes a steam nozzle, a liquid nozzle, and a mixing section; the steam nozzle and the liquid nozzle are both connected to the mixing section, and the liquid nozzle is located on the outer periphery of the steam nozzle; the steam nozzle is connected to the steam outlet of the evaporator; the liquid nozzle is connected to the outlet of the second condenser.

[0008] Further, both the steam nozzle and the mixing section are Laval nozzles.

[0009] Further, the mixing section includes a mixing chamber, a throat, and a diffuser section that are connected in sequence; the diffuser section is connected to the inlet of the first condenser; the large-end size of the steam nozzle is 1-2 mm; the throat size of the steam nozzle is 0.6-1.2 mm; the throat size of the mixing section is 1-1.2 mm.

[0010] Further, the liquid nozzle is connected to the second condenser through a second liquid pipeline; the second liquid pipeline is inserted into the vapor-liquid two-phase ejector boosting device at circumferential angles of 30°-60° and axial angles respectively.

[0011] Further, the evaporator includes a bottom plate and a compensation chamber provided on the bottom plate; a capillary wick is provided below the compensation chamber; a steam channel is provided below the capillary wick; a gas collection groove communicating with the steam channel is provided on the side of the steam channel; the gas collection groove is connected to the steam nozzle of the vapor-liquid two-phase ejector boosting device through a first steam pipeline.

[0012] Further, the capillary wick includes an upper layer of the capillary wick and a lower layer of the capillary wick; the lower layer of the capillary wick is sintered with brass powder of 800-1200 meshes; the upper layer of the capillary wick is sintered with nickel powder of 300-500 meshes.

[0013] Further, the capillary wick and the bottom plate are integrally sintered and formed.

[0014] Further, a plurality of square column microstructures are provided on the bottom plate of the boiling pool; there are gaps between adjacent square column microstructures; micron-sized particles are sintered on the surface of the square column microstructures; a microporous structure is formed between the micron-sized particles.

[0015] Further, there are a plurality of evaporators and boiling pools; a plurality of evaporators are arranged in parallel, and a plurality of boiling pools are arranged in series or in parallel.

[0016] The present application has the following beneficial effects compared with the prior art:

[0017] 1. In the embodiment of the present application, by adding a vapor-liquid two-phase ejector booster device at the combined outlet of the evaporator and the boiling pool, not only does the radiator not require an external power source and has no moving parts, greatly increasing the reliability of the device, but also only a small amount of heat needs to be applied to the evaporator to generate steam. Subsequently, the steam enters the ejector compensation chamber of the vapor-liquid two-phase ejector booster device to eject dozens of times of subcooled liquid into the cavity of the boiling pool to form a flow boiling heat transfer effect, successfully solving the problem of insufficient liquid supply in the boiling pool. Furthermore, an excellent flow boiling heat transfer effect is achieved, with a high critical heat flux density, capable of efficiently dissipating heat from high heat flux density electronic devices.

[0018] 2. In the embodiment of the present application, by optimizing the parameters of the internal components of the vapor-liquid two-phase ejector booster, a higher pressure ratio and ejector ratio are achieved, thereby improving the performance and efficiency of the radiator.

[0019] 3. In the embodiment of the present application, by setting up a vapor-liquid two-phase ejector booster device and setting the inlet of the ejected liquid in the compensation chamber on the back of the evaporator, the liquid heated due to "heat leakage" in the compensation chamber is removed through the ejection action of the steam and replaced with fresh cold liquid to form a hot and cold fluid exchange, which can solve the instability problem caused by "heat leakage".

[0020] 4. The vapor-liquid two-phase ejector booster device in the embodiment of the present application is composed of a convergent-divergent steam nozzle and a variable cross-section mixing section connected in series. The steam expands and accelerates in the nozzle to form a local negative pressure, ejecting subcooled liquid into the mixing chamber to directly contact and condense to form a supersonic vapor-liquid two-phase flow, generating a condensation shock wave near the throat to achieve a sudden pressure rise, and then continuously boosting the pressure in the diffusion zone to form high-pressure liquid, completing the conversion of the internal energy of the steam into the pressure energy of the liquid.

[0021] 5. In the boiling pool of the embodiment of the present application, a plurality of square column microstructures are provided, and there are gaps between adjacent square column microstructures; micron-sized particles are sintered on the surface of the square column microstructures, and a microporous structure is formed between the micron-sized particles, with the distribution characteristics of nanoscale clusters. The existence of the nanoclusters forms numerous vaporization nuclei, thus significantly enhancing the convective boiling heat transfer coefficient. At the same time, the micropores between the particles effectively enhance the capillary liquid supply ability of the wall surface, and the gaps between the microcolumns provide channels for the flow of the near-wall micro-liquid layer, significantly increasing the critical heat flux density. In addition, due to the dense distribution of vaporization nuclei in the nanoclusters, small bubbles frequently merge during the growth process, and the excess surface energy is converted into the kinetic energy of the merged large bubbles detaching from the wall surface, thus generating a bubble bounce detachment effect, effectively overcoming the problem of insufficient bubble detachment driving force. Description of the Drawings

[0022] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 It is a schematic diagram of the operation of the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0024] Figure 2 It is a schematic diagram of the structure of the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0025] Figure 3 It is a schematic diagram of the structure of the evaporator in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0026] Figure 4 It is a schematic diagram of the structure of multiple evaporators in parallel in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0027] Figure 5 It is a schematic diagram of the structure of the capillary wick in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0028] Figure 6 It is a schematic diagram of the structure of the vapor-liquid two-phase ejector booster device in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0029] Figure 7 It is a schematic diagram of the circumferential inclination of the vapor-liquid two-phase ejector booster device in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0030] Figure 8 It is a schematic diagram of the axial inclination of the vapor-liquid two-phase ejector booster device in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0031] Figure 9 It is a schematic diagram of the structure of the boiling pool in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0032] Figure 10 It is a schematic diagram of the parallel structure of the boiling pools in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application;

[0033] Figure 11 It is a schematic diagram of the series structure of the boiling pools in the novel mechanical-pump-free flow boiling radiator according to the embodiment of the present application. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0035] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0036] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; for those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0037] The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "plurality" is two or more.

[0038] Refer to Figures 1 to 11 , the embodiments of the present application provide a new type of mechanical pump-free flow boiling radiator, including an evaporator 1, a vapor-liquid two-phase ejector booster device 2, a first condenser 3, a boiling pool 4, and a second condenser 5.

[0039] The steam outlet of the evaporator 1 is connected to the gas-phase inlet of the vapor-liquid two-phase ejector booster device 2 through the first steam pipeline 6, and the liquid outlet of the evaporator 1 is connected to the inlet of the boiling pool 4 through the first liquid pipeline 7. The outlet of the boiling pool 4 is connected to the inlet of the second condenser 5 through the second steam pipeline 8, and the outlet of the second condenser 5 is connected to the liquid-phase inlet of the vapor-liquid two-phase ejector booster device 2 through the second liquid pipeline 9. The outlet of the vapor-liquid two-phase ejector booster device 2 is connected to the inlet of the first condenser 3 through the third liquid pipeline 10, and the outlet of the first condenser 3 is connected to the inlet of the evaporator 1 through the fourth liquid pipeline 11.

[0040] Refer to Figures 1 to 3, the evaporator 1 adopts a square columnar or cylindrical structure. To ensure airtightness, the entire evaporator 1 is diffusion-welded. The evaporator 1 includes a bottom plate 101, a gas collecting groove 102, a steam channel 103, a capillary wick 104, and a compensation chamber 105. The capillary wick 104 is arranged at the central vacancy of the bottom plate, and the compensation chamber 105 is arranged above the capillary wick 104 and is connected to both the bottom plate 101 and the side wall of the evaporator 1. The capillary wick 104 can provide capillary driving force. A steam channel 103 is arranged below the capillary wick 104, and a gas collecting groove 102 communicating with the steam channel 103 is arranged on the right side of the steam channel 103. The gas collecting groove 102 is communicated with the gas phase inlet of the vapor-liquid two-phase ejector booster device 2 through the first steam pipeline 6. The gas collecting groove 102 and the steam channel 103 are precisely machined on the bottom plate by mechanical processing methods.

[0041] Due to the low surface tension of low-boiling-point working fluids, it is difficult to form a stable pressure difference. Therefore, the capillary wick inside the evaporator needs to have the conditions of low heat leakage and large capillary force. Therefore, referring to Figure 5 , in the embodiment of the present application, the capillary wick 104 is arranged in layers during preparation. Specifically, the capillary wick 104 includes an upper capillary wick layer 0141 and a lower capillary wick layer 1042. The lower capillary wick layer 1042 is sintered with high-mesh brass powder of 800 mesh to 1200 mesh. The upper capillary wick layer 0141 is sintered with low-mesh nickel powder of 300 mesh to 500 mesh to reduce heat leakage and the flow resistance inside the capillary wick. In addition, the capillary wick 104 and the bottom plate 101 are combined by an integrated sintering technology. It should be noted that in order to adapt to the conditions of multiple chip heat sources, referring to Figure 4 , in the embodiment of the present application, there can also be multiple evaporators 1, and multiple evaporators 1 are arranged in parallel.

[0042] Referring to Figures 6 to 8 , the vapor-liquid two-phase ejector booster device 2 includes a steam nozzle 21, a liquid nozzle 22, and a mixing section 23. Both the steam nozzle 21 and the liquid nozzle 22 are communicated with the mixing section 23, and the liquid nozzle 22 is located on the outer periphery of the steam nozzle 21, that is, the liquid nozzle 22 is an annular gap formed by the outlet of the steam nozzle 21 and the inlet of the mixing section 23.

[0043] Both the steam nozzle 21 and the mixing section 23 are Laval nozzles. The mixing section 23 includes a mixing chamber 231, a throat 232, and a diffusion zone 233 that are connected in sequence. The mixing chamber 231 is communicated with the outlets of the steam nozzle 21 and the liquid nozzle 22, and the diffusion zone 233 is communicated with the inlet of the first condenser 3 through the third liquid pipeline 10. The inlet of the steam nozzle 21 is communicated with the steam outlet of the evaporator 1 through the first steam pipeline 6, and the inlet of the liquid nozzle 22 is communicated with the outlet of the second condenser 5 through the fourth liquid pipeline 11.

[0044] The large end size of the steam nozzle 21 is 1 - 2 mm, the size of the throat 232 of the steam nozzle 21 is 0.6 - 1.2 mm, and the size of the throat 232 of the mixing section 23 is 1 - 1.2 mm. Thus, a higher pressure boost ratio and entrainment ratio can be achieved, thereby improving the performance and efficiency of the overall equipment.

[0045] In addition, since the size of the vapor-liquid two-phase ejector pressure booster 2 is small to adapt to the narrow space of electronic components, it is difficult to achieve with conventional machining methods. Therefore, the vapor-liquid two-phase ejector pressure booster 2 in the embodiments of this application is processed by precision electric discharge machining or 3D printing.

[0046] Refer to Figure 7 and Figure 8 , the fourth liquid pipeline 11 is inserted into the vapor-liquid two-phase ejector pressure booster 2 at circumferential angles and axial angles of 30° - 60° respectively, that is, the fourth liquid pipeline 11 is arranged at an inclined circumferential angle and axial angle of 30° - 60° towards the liquid inlet direction. Thus, the flow impact during liquid entry can be effectively reduced.

[0047] Refer to Figure 9 , the pool boiling of the boiling pool 4 occurs in a small square column or cylindrical cavity, that is, the boiling pool cavity 41, and the boiling pool 4 is combined by diffusion welding. A plurality of square column microstructures 43 are provided on the bottom surface 42 of the boiling pool 4, and there are gaps between adjacent square column microstructures 43. A capillary structure, that is, micron-sized particles, is sintered on the surface of the square column microstructures 43, and a microporous structure is formed between the micron-sized particles. The cavity of the boiling pool 4 has a gradually expanding, straight, and gradually shrinking shape, which can effectively reduce the flow resistance. Refer to Figure 10 and Figure 11 , in order to adapt to the conditions of multiple chip heat sources, there can also be multiple boiling pools 4 in the embodiments of this application, and the multiple boiling pools 4 can be arranged in series or in parallel.

[0048] The working principle of the embodiments of this application is as follows:

[0049] The wall surface of the evaporator 1 is closely combined with the secondary heat - generating surface of the electronic component, and the heat is conducted through the metal outer wall of the evaporator 1 to the capillary wick 104. On the surface of the capillary wick 104, the liquid is heated and vaporized, and at the same time, a meniscus is formed at the gas - liquid interface, generating capillary force. The resulting vapor enters the first steam pipeline 6 through the steam channel 103 and the gas - collecting tank 102. The speed of the steam at the nozzle quickly increases to supersonic speed, and a low - pressure area is formed at the outlet of the steam nozzle 21, thus effectively ejecting the sub - cooled working fluid that has been condensed in the second condenser 5 and smoothly introducing it into the mixing section 23. In the mixing section 23, the supersonic steam flow directly contacts the sub - cooled liquid and condenses, and then gradually achieves uniform mixing. During this process, a condensation shock wave is formed at the throat 232 or slightly behind it, and the steam releases energy when condensing. After passing through the diffusion section 233, part of the kinetic energy of the single - phase water is converted into potential energy, the flow velocity decreases, and the pressure further increases. Finally, a high - pressure single - phase fluid is formed and flows into the first condenser 3 through the third liquid pipeline 10 for treatment.

[0050] The bottom surface of the boiling pool 4 is in close contact with the main heat - generating surface of the electronic component, and the heat is effectively conducted to the liquid working fluid in the pool through the bottom plate 101 and the square - column micro - structure 42. During this process, the liquid is evaporated due to heating, and then nucleate boiling is formed. The generated steam flows to the second condenser 5 through the second steam pipeline 8, where it releases heat. In the second condenser 5, the cooled liquid is then introduced into the liquid nozzle 22 through the second liquid pipeline 9 to complete the liquid recirculation process. During the working process of the embodiment of the present application, the system mainly relies on two driving force sources. Firstly, it is the capillary force generated by the capillary wick 104, and secondly, it is the pressure - boosting performance provided by the vapor - liquid two - phase ejector booster device 2. These two together provide power support for the system. The evaporator 1, as an auxiliary facility, generates steam at a lower power to drive the normal operation of the vapor - liquid two - phase ejector booster, extracts the liquid - phase working fluid in the compensation chamber to ensure the continuous supply of the liquid - phase working fluid in the boiling pool 4. This mechanism effectively promotes the occurrence of flow boiling, thereby achieving efficient heat dissipation of the electronic device.

[0051] In the prior art, the working fluid of the vapor - liquid two - phase flow jet booster device is mainly water. In order to reduce the operating temperature of the heat pipe in the present invention, the working fluid is a low - boiling - point working fluid, such as HP, 7DA, and EC, etc.

[0052] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any change or replacement within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A new type of mechanical pump-free flow boiling radiator, characterized in that: It includes an evaporator, a vapor-liquid two-phase injection boosting device, a first condenser, a boiling pool and a second condenser; the steam outlet of the evaporator is connected to the vapor phase inlet of the vapor-liquid two-phase injection boosting device, and the liquid phase outlet of the evaporator is connected to the inlet of the boiling pool; the outlet of the boiling pool is connected to the inlet of the second condenser, and the outlet of the second condenser is connected to the liquid phase inlet of the vapor-liquid two-phase injection boosting device; the outlet of the vapor-liquid two-phase injection boosting device is connected to the inlet of the first condenser, and the outlet of the first condenser is connected to the inlet of the evaporator.

2. The novel mechanical pump-free flow boiling radiator according to claim 1 is characterized in that: The vapor-liquid two-phase injection boosting device includes a steam nozzle, a liquid nozzle and a mixing section; the steam nozzle and the liquid nozzle are both connected to the mixing section, and the liquid nozzle is located at the periphery of the steam nozzle; the steam nozzle is connected to the steam outlet of the evaporator; the liquid nozzle is connected to the outlet of the second condenser.

3. The novel mechanical pump-free flow boiling radiator according to claim 2 is characterized in that: The steam nozzle and the mixing section are both Laval nozzles.

4. The novel mechanical pump-free flow boiling radiator according to claim 3 is characterized in that: The mixing section includes a mixing chamber, a throat and a diffusion zone which are connected in sequence; the diffusion zone is connected to the inlet of the first condenser; the large end size of the steam nozzle is 1 to 2 mm; the throat size of the steam nozzle is 0.6 to 1.2 mm; and the throat size of the mixing section is 1 to 1.2 mm.

5. The novel mechanical pump-free flow boiling radiator according to claim 4 is characterized in that: The liquid nozzle is connected to the second condenser through a second liquid pipeline; the second liquid pipeline is inserted into the vapor-liquid two-phase injection boosting device at an annular angle of 30° to 60° and an axial angle respectively.

6. The novel mechanical pump-free flow boiling radiator according to claim 5 is characterized in that: The evaporator includes a bottom plate and a compensation chamber arranged on the bottom plate; a capillary core is arranged below the compensation chamber; a steam channel is arranged below the capillary core; a gas collecting groove connected to the steam channel is arranged on the side of the steam channel; the gas collecting groove is connected to the steam nozzle of the vapor-liquid two-phase injection boosting device through a first steam pipeline.

7. The novel mechanical pump-free flow boiling radiator according to claim 6 is characterized in that: The capillary core comprises a capillary core upper layer and a capillary core lower layer; the capillary core lower layer is sintered with brass powder of 800-1200 meshes; the capillary core upper layer is sintered with nickel powder of 300-500 meshes.

8. The novel mechanical pump-free flow boiling radiator according to claim 7 is characterized in that: The capillary core and the bottom plate are formed by integrating sintering technology.

9. The novel mechanical pump-free flow boiling radiator according to claim 8 is characterized in that: A plurality of square column microstructures are arranged on the bottom plate of the boiling pool; gaps are provided between adjacent square column microstructures; micron-sized particles are sintered on the surfaces of the square column microstructures; and microporous structures are formed between the micron-sized particles.

10. The novel mechanical pump-free flow boiling radiator according to claim 9 is characterized in that: There are multiple evaporators and boiling pools; multiple evaporators are arranged in parallel, and multiple boiling pools are arranged in series or in parallel.

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