Adaptive flow distribution joint system of parallel two-phase flow cooling system

Abstract

The invention discloses a flow self-adaptive distribution joint system for a parallel two-phase flow cooling system, which is characterized in that a converging section is connected with an external liquid supply system of the two-phase flow cooling system, a shunting section is connected with a parallel cooling branch of the two-phase flow cooling system, and cooling liquid subjected to self-adaptive distribution flows into the parallel cooling branch; the throttling section and the distribution adjusting section jointly achieve flow self-adaptive distribution of the cooling system. According to the scheme, the flow resistance of the high-flow branch is increased by utilizing the characteristic that the throttling of the throttling section causes large local resistance loss, and then the elastic film is guided to deform by utilizing the flow characteristic that the static pressure of the high-flow branch in the distribution adjusting section is low, so that the flow section of the high-flow branch is reduced, and the flow resistance of the high-flow branch is further increased; and the low-flow branch flow is adaptively improved. The flow self-adaptive joint is simple and compact in structure and high in reliability, is completely decoupled from a rear-end evaporator form, can realize flow regulation and control of a parallel two-phase flow cooling system, and improves the cost-efficiency ratio and the stability of equipment operation.

Description

Technical Field

[0001] This invention belongs to the field of thermal control of electronic devices, and specifically relates to a flow adaptive distribution connector system for a parallel two-phase flow cooling system. Background Technology

[0002] The increasing power and integration of electronic devices present new challenges to cooling technology. Two-phase cooling is a preferred solution for cooling high-power electronic components. Utilizing the isothermal and high heat transfer coefficient characteristics of the circulating working fluid during phase change, two-phase cooling can achieve effective thermal control of high-heat-density power devices under low mass flow rates. Most two-phase cooling systems are parallel systems. For evaporators with different heat loads, the varying heat levels result in different flow resistances within each evaporator. Evaporators with higher heat loads have relatively higher flow resistance, leading to less flow distribution in that branch. This deteriorates heat dissipation in that branch, affecting the performance of electronic devices and potentially causing thermal failure. Therefore, flow distribution in parallel branches is becoming a prominent issue in the research and application of two-phase cooling systems.

[0003] To address the aforementioned issues, the main technical solutions fall into three categories: increasing the total liquid supply flow rate, installing a rectifier at the inlet, and adaptive flow control of the evaporator. Simply increasing the liquid supply flow rate significantly increases the volume of the two-phase flow system, leading to higher energy consumption and negating the inherent advantages of efficient heat dissipation in two-phase flow systems. Installing a rectifier at the inlet is a commonly used solution in industry.

[0004] For example, CN104457046A discloses a rectifier nozzle type equal flow distributor and refrigeration system. By using swirl vanes and a fluid rectifier, the flow pattern of the gas-liquid two-phase refrigerant after expansion and throttling is adjusted to an ideal annular flow. Then, the liquid is uniformly supplied to each flow path of the evaporator through the distribution nozzles in front of each flow path. The gas-liquid two-phase refrigerant in each flow path reaches the critical point of the local speed of sound at the throat of each distribution nozzle, so that the flow rate of each branch is not affected by adverse factors such as the resistance of each flow path of the downstream evaporator and the liquid supply height difference, thereby achieving equal flow liquid supply in each branch and improving the heat exchange performance of the evaporator. Authorization announcement number CN101762201B discloses a flute-shaped flow equalizer for uniform two-phase flow distribution in header branch pipes. By installing concentric flute-shaped tubes inside the header, and connecting the inlet pipe radially or axially from the header body to the flute-shaped tubes, the pressure of the fluid within the header body is kept essentially uniform. Therefore, the flow rate of the fluid flowing into the branch pipes is essentially the same, greatly improving the two-phase flow distribution characteristics in the header branch pipes and achieving uniform two-phase flow distribution. Inlet rectifiers come in various forms, but they generally sacrifice significant resistance losses for uniform branch flow distribution.

[0005] Adaptive flow control of evaporators has become a hot research topic in academia and industry recently. Patent publication CN104457046A discloses a dynamic flow control device for overheating prevention in two-phase flow systems. This device utilizes a spring, a fixed valve core, and a moving valve core to dynamically adjust the flow rate. When changes in evaporator load lead to changes in flow resistance, the spring force dynamically adjusts the flow area of ​​the moving valve core to ensure branch flow. Patent publication CN111629572 discloses an adaptive flow control device for liquid-cooled cold plates in electronic devices. By adding a thermal expansion component to a conventional cold plate structure, the cross-sectional area of ​​the liquid-cooled cold plate's flow channel adapts to the temperature of the electronic components, improving the stability and safety of the phase change cooling system.

[0006] However, the adaptive adjustment mechanism of the aforementioned patent in the prior art is similar to that of traditional refrigeration systems, with a complex structure, large size, and high cost, and is not conducive to integration design with the front end. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a flow adaptive distribution connector system for a parallel two-phase flow cooling system. This connector features a simple and compact structure, high reliability, low resistance loss, and adaptive flow distribution functionality. It adaptively reduces the flow rate of the high-flow-rate fluid by utilizing the difference in local resistance loss caused by throttling and elastic film deformation within the high-flow-rate and low-flow-rate channels.

[0008] The specific technical solution for achieving the objective of this invention is as follows:

[0009] A flow adaptive distribution connector system for a parallel two-phase flow cooling system includes a confluence section, a throttling section, a distribution and adjustment section, and a flow splitting section;

[0010] The confluence section, throttling section, distribution and regulation section, and diversion section are connected in sequence to form a connecting flow channel;

[0011] The confluence section is connected to the external two-phase flow cooling system supply system for receiving coolant.

[0012] The flow divider is connected to the parallel cooling branch of the two-phase flow cooling system, and the adaptively distributed coolant flows into the parallel cooling branch.

[0013] The throttling section and the distribution adjustment section together achieve adaptive flow distribution of the cooling system.

[0014] Furthermore, a partition plate is provided in the center of the flow channel of the throttling section and the distribution adjustment section; the flow channel is divided into two independent chambers, which are respectively connected to two independent flow channels of the diversion section, so that the coolant flows into the parallel cooling branch respectively.

[0015] Furthermore, the partition plate includes a metal structural component and a non-metallic elastic membrane;

[0016] The metal structural component is used to separate the flow channels of the throttling section and the distribution and regulation section. A non-metallic elastic membrane is provided in the metal structural component of the distribution and regulation section. The non-metallic elastic membrane deforms under the pressure difference of the two flow channels, changing the flow cross section of the working fluid, so as to realize the adaptive distribution of the flow rate in the distribution and regulation section.

[0017] Furthermore, the process by which the non-metallic elastic membrane achieves adaptive flow distribution in the distribution regulation section is as follows:

[0018] When the heat load of parallel cooling branches changes, the flow velocity in the branch with higher heat load decreases due to the increased dryness of the working fluid, while the flow velocity in the branch with lower heat load increases.

[0019] The increased flow velocity in the branch with lower heat load leads to higher local resistance loss due to throttling in the distribution and regulation section of the corresponding flow channel, resulting in a larger dynamic head and significantly lower static pressure compared to the other flow channel. Consequently, the non-metallic elastic membrane deforms towards the flow channel side corresponding to the branch with lower heat load, causing compression of the flow channel cross-section on that side and increasing the resistance to fluid flow. Ultimately, the cross-section of the distribution and regulation section of the flow channel corresponding to the branch with higher heat load increases, and the flow rate of the cooling liquid also increases accordingly.

[0020] Furthermore, the material of the non-metallic elastic membrane includes hydrogenated nitrile rubber, neoprene rubber, or other rubber products compatible with the refrigeration system.

[0021] Furthermore, the elastic modulus of the non-metallic elastic membrane ranges from 0.005 GPa to 0.02 GPa.

[0022] Furthermore, the cross-sections of the confluence section, throttling section, distribution and adjustment section, and diversion section are circular, elliptical, and rectangular;

[0023] When the flow channel cross-section is rectangular, the direction perpendicular to the non-metallic elastic membrane in the flow channel is the short side of the rectangle.

[0024] Furthermore, the ratio of the total cross-sectional area of ​​the confluence section to the total cross-sectional area of ​​the distribution and regulating section is 4:1 to 10:1;

[0025] The ratio of the total cross-sectional area of ​​the confluence section to the total cross-sectional area of ​​each branch section is 1.5:1 to 2.5:1.

[0026] Furthermore, the metal structural component is made of copper.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] The solution of the present invention passively increases the flow rate of the low-flow branch in a two-phase parallel branch through the adaptive adjustment of the distributor;

[0029] Specifically, based on the phenomenon that the flow velocity of the high-flow-rate branch is relatively large, the flow resistance of the high-flow-rate branch is first increased by taking advantage of the large local resistance loss caused by the throttling section. Then, the flow characteristics of the low static pressure of the high-flow-rate branch in the distribution and regulation section are used to guide the deformation of the elastic membrane, reduce the flow cross section of the high-flow-rate branch, further increase the flow resistance of the high-flow-rate branch, and adaptively increase the flow rate of the low-flow-rate branch.

[0030] The flow adaptive connector of the present invention has a simple and compact structure, high reliability, and is completely decoupled from the downstream evaporator. It can realize flow regulation of parallel two-phase flow cooling system, improve the cost-effectiveness and stability of equipment operation.

[0031] The present invention will be further described below with reference to specific embodiments. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the flow adaptive distribution connector system of the parallel two-phase flow cooling system of the present invention.

[0033] Figure 2 This is a schematic diagram of the partition plate structure of the present invention.

[0034] Figure 3 This is a schematic diagram illustrating the working principle of the flow adaptive distribution connector system of the parallel two-phase flow cooling system of the present invention. Detailed Implementation

[0035] Example

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0038] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0039] Combination Figure 2 A flow adaptive distribution connector system for a parallel two-phase flow cooling system includes a confluence section 1, a throttling section 2, a distribution and adjustment section 3, and a flow splitting section 4;

[0040] The confluence section 1, throttling section 2, distribution and regulation section 3, and diversion section 4 are connected in sequence to form a connecting flow channel;

[0041] The connection between the confluence section 1 and the external two-phase flow cooling system liquid supply system is used to connect the coolant and form a stable liquid static pressure chamber.

[0042] The flow divider section 4 is connected to the parallel cooling branch of the two-phase flow cooling system, and the adaptively distributed coolant flows into the parallel cooling branch.

[0043] The throttling section 2 and the distribution adjustment section 3 increase the incoming flow velocity, together achieving adaptive flow distribution of the cooling system.

[0044] The ratio of the total cross-sectional area of ​​the confluence section 1 to the total cross-sectional area of ​​the distribution and adjustment section 3 is 4:1 to 10:1; the ratio of the total cross-sectional area of ​​the confluence section 1 to the total cross-sectional area of ​​each branch section 4 is 1.5:1 to 2.5:1.

[0045] Specifically, a partition plate 5 is provided in the center of the flow channel of the throttling section 2 and the distribution regulating section 3; the flow channel is divided into two independent chambers, which are respectively connected to the two independent flow channels of the diversion section 4, so that the coolant flows into the parallel cooling branch respectively.

[0046] Combination Figure 2 The partition plate 5 includes a metal structural component 501 and a non-metallic elastic membrane 502;

[0047] The metal structural component 501 is used to separate the flow channels of the throttling section and the distribution and regulation section. The metal structural component 501 extends from the throttling section to the distribution section. A non-metallic elastic membrane 502 is provided in the metal structural component 501 of the distribution and regulation section. The non-metallic elastic membrane 502 deforms under the pressure difference between the two flow channels, changing the flow cross-section of the working fluid to achieve adaptive flow distribution in the distribution and regulation section. The metal structural component 501 is made of copper.

[0048] The non-metallic elastic membrane 502 is made of hydrogenated nitrile rubber, neoprene rubber, or other rubber products compatible with refrigeration systems, and the elastic modulus of the non-metallic elastic membrane 502 ranges from 0.005 GPa to 0.02 GPa.

[0049] The flow channels of the confluence section 1, throttling section 2, distribution and adjustment section 3, and diversion section 4 have circular, elliptical, and rectangular cross-sections, with a rectangular shape being preferred here, and the shorter side of the rectangle being perpendicular to the direction of the non-metallic elastic membrane.

[0050] In some embodiments, the throttling section 1, the throttling section 2, the distribution and adjustment section 3, and the diversion section 4 are connected by integral welding. In other embodiments, the throttling section 2, the distribution and adjustment section 3, and the diversion section 4 of the two flow channels can be processed into a single component, and then the component of the two flow channels can be screwed together and then welded to the throttling section 1 as a whole. In this case, there are two layers of non-metallic elastic membrane.

[0051] Combination Figure 3 The process by which the non-metallic elastic membrane achieves adaptive flow distribution in the distribution and regulation section is as follows:

[0052] When the heat load of parallel cooling branches changes, the flow velocity in the branch with higher heat load decreases due to the increased dryness of the working fluid, while the flow velocity in the branch with lower heat load increases.

[0053] The increased flow velocity in the branch with lower heat load leads to higher local resistance loss due to throttling in the distribution and regulation section of the corresponding flow channel, resulting in a larger dynamic head and significantly lower static pressure compared to the other flow channel. Consequently, the non-metallic elastic membrane 502 deforms towards the flow channel side corresponding to the branch with lower heat load, causing compression of the flow channel cross-section on that side and increasing the resistance to fluid flow. Ultimately, the cross-section of the distribution and regulation section of the flow channel corresponding to the branch with higher heat load increases, and the flow rate of the cooling liquid also increases accordingly.

[0054] This scheme provides a detailed analysis of the resistance changes during parallel two-phase flow:

[0055] According to Bernoulli's equation, for ideal, steady, incompressible flow, the fluid parameters along the streamline direction follow the following expression:

[0056]

[0057] In the formula: It is the hydrostatic pressure of the fluid; For fluid density, denoted as fluid velocity, g as gravitational acceleration, and h as the height of the fluid's location.

[0058] For actual flow, resistance losses occur due to wall friction and changes in the flow channel cross-section. Ignoring height changes, the pressure expression at a point in the flow channel is:

[0059]

[0060] In the formula: It is the hydrostatic pressure of the fluid; This is the fluid friction resistance loss. This is the loss due to local fluid resistance. This is the friction coefficient. is the local drag coefficient, is the flow channel length, and is the equivalent diameter of the flow channel.

[0061] For parallel systems, the fluid pressure drop in each branch is always consistent due to the presence of distribution and collection lines. For single-phase flow, the velocity (i.e., flow rate) in different branches depends entirely on the flow channel structure; for two-phase flow, the branch pressure drop also depends on the mass fraction of the gas phase in the pipeline, i.e., dryness fraction.

[0062] The formula for calculating friction loss in a two-phase pipeline is:

[0063]

[0064] In the formula, Vs is the apparent velocity of the working fluid, and λs is the apparent friction factor of the working fluid. The calculation formula is as follows:

[0065]

[0066] In the formula, α represents the dryness degree.

[0067] For Res <1500

[0068]

[0069] For Res ≥1500

[0070]

[0071]

[0072] In the above formula, all physical properties are taken as gas physical property parameters.

[0073]

[0074] In the formula, C is determined based on the liquid and gas flow regimes. The value of X can be determined by the following formula:

[0075]

[0076] The formula for calculating local resistance loss in a two-phase pipeline is as follows:

[0077]

[0078] In the formula, α is the dryness fraction, and pj' is the local resistance of the gas pipeline when the gas is in the liquid phase.

[0079] Therefore, in parallel branches of two-phase flow, due to the different heat loads of each branch, more working fluid vaporizes under high heat load, increasing the dryness of that branch. The increase in dryness leads to a significant increase in friction loss and local resistance loss along the branch, passively reducing the flow rate of that branch and further worsening heat transfer.

[0080] Based on this scheme, the joint system has negligible friction loss due to the short pipe length. The static pressure of the two-branch distribution regulating section of the branch with a larger heat load is:

[0081]

[0082] Branch 2 is the branch with a larger heat load. The flow velocity v2 is lower than the fluid flow velocity v1 in branch 1. The static pressure of the fluid in branch 2 is greater than that in branch 1, which compresses the flow cross section of channel 1 and increases the local resistance of the fluid flow in channel 1.

[0083] For example, when the downstream evaporator in channel 2 experiences a higher heat load, leading to increased working fluid dryness and increased flow resistance, the flow rate in channel 2 decreases further, while the flow velocity in channel 1 is significantly higher than in channel 2. This higher velocity results in higher local resistance losses due to throttling in the distribution and regulation section of channel 1, leading to a larger dynamic head and significantly lower static pressure than in channel 2. The non-metallic elastic membrane 502 deforms towards channel 1, compressing the flow cross-section and increasing the local resistance of the fluid flow within channel 1. By leveraging the difference in the increase in local resistance losses caused by throttling and elastic membrane deformation between the high-flow-rate and low-flow-rate channels, the flow rate of the high-flow-rate fluid is adaptively reduced.

[0084] Therefore, the connector system of this solution can be used to achieve adaptive flow regulation of the two downstream cooling branches. Furthermore, the connector system of this solution can be used individually or in series to achieve adaptive flow regulation of multiple branches.

[0085] The embodiments described above are merely one implementation method of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A flow adaptive distribution connector system for a parallel two-phase flow cooling system, characterized in that, This includes the merging section, throttling section, distribution and regulation section, and diversion section; The confluence section, throttling section, distribution and regulation section, and diversion section are connected in sequence to form a connecting flow channel; The confluence section is connected to the external two-phase flow cooling system supply system for receiving coolant. The flow divider is connected to the parallel cooling branch of the two-phase flow cooling system, and the adaptively distributed coolant flows into the parallel cooling branch. The throttling section and the distribution adjustment section together achieve adaptive flow distribution of the cooling system.

2. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to claim 1, characterized in that, A partition plate is provided in the center of the flow channel of the throttling section and the distribution and adjustment section; the flow channel is divided into two independent chambers, which are respectively connected to two independent flow channels of the branch section, so that the coolant flows into the parallel cooling branch respectively.

3. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to claim 2, characterized in that, The partition plate includes metal structural components and a non-metallic elastic membrane; The metal structural component is used to separate the flow channels of the throttling section and the distribution and regulation section. A non-metallic elastic membrane is provided in the metal structural component of the distribution and regulation section. The non-metallic elastic membrane deforms under the pressure difference of the two flow channels, changing the flow cross section of the working fluid, so as to realize the adaptive distribution of the flow rate in the distribution and regulation section.

4. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to claim 3, characterized in that, The process by which the non-metallic elastic membrane achieves adaptive flow distribution in the distribution regulation section is as follows: When the heat load of parallel cooling branches changes, the flow velocity in the branch with higher heat load decreases due to the increased dryness of the working fluid, while the flow velocity in the branch with lower heat load increases. The increased flow velocity in the branch with lower heat load leads to higher local resistance loss due to throttling in the distribution and regulation section of the corresponding flow channel, resulting in a larger dynamic head and significantly lower static pressure compared to the other flow channel. Consequently, the non-metallic elastic membrane deforms towards the flow channel side corresponding to the branch with lower heat load, causing compression of the flow channel cross-section on that side and increasing the resistance to fluid flow. Ultimately, the cross-section of the distribution and regulation section of the flow channel corresponding to the branch with higher heat load increases, and the flow rate of the cooling liquid also increases accordingly.

5. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to claim 3, characterized in that, The material of the non-metallic elastic membrane includes hydrogenated nitrile rubber, neoprene rubber, or other rubber products compatible with the refrigeration system.

6. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to claim 3, characterized in that, The elastic modulus of the non-metallic elastic membrane ranges from 0.005 GPa to 0.02 GPa.

7. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to claim 2, characterized in that, The cross-sections of the confluence section, throttling section, distribution and regulation section, and diversion section are circular, elliptical, and rectangular; When the flow channel cross-section is rectangular, the direction perpendicular to the non-metallic elastic membrane in the flow channel is the short side of the rectangle.

8. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to any one of claims 1-7, characterized in that, The ratio of the total cross-sectional area of ​​the confluence section to the total cross-sectional area of ​​the distribution and regulation section is 4:1 to 10:1; The ratio of the total cross-sectional area of ​​the confluence section to the total cross-sectional area of ​​each branch section is 1.5:1 to 2.5:

1.

9. The flow adaptive distribution connector system for a parallel two-phase flow cooling system according to claim 3, characterized in that, The metal structural component is made of copper.

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