A high-efficiency passive heat dissipation system based on particle movement

Abstract

This invention discloses a high-efficiency passive heat dissipation system based on particle movement, belonging to the field of enhanced boiling heat dissipation. By arranging movable particles at the bottom of the boiling pool, boiling heat transfer is promoted, and the particle movement enhances flow field disturbance and strengthens boiling. The kinetic energy of phase change steam drives the circulation of the working fluid to achieve passive heat dissipation. The microparticles contain a hydrophilic porous structure, maintaining a liquid-wetted state during the boiling phase change heat transfer process, ensuring adhesion and migration to the phase change interface during boiling. The movable particles provide vaporization nuclei for the boiling zone at the heat source point within the boiling pool, carrying heat into the fluid region, thereby enhancing boiling heat transfer. The particle movement causes disturbance to the fluid within the boiling pool; falling particles disrupt large bubbles and vapor films on the heating surface, accelerating bubble detachment and delaying vapor film formation. Simultaneously, this increases the temperature in the fluid region, achieving a continuous boiling effect in the fluid region.

Description

Technical Field

[0001] This invention relates to the field of enhanced boiling heat dissipation technology, and more specifically, to a high-efficiency passive heat dissipation system based on particle movement. Background Technology

[0002] With the soaring integration and power density of electronic chips, heat dissipation has become a critical bottleneck. Conventional air cooling is proving inadequate, failing to meet the temperature control requirements for stable chip operation over extended periods. The miniaturized boiling pool heat dissipation solution has emerged to address this challenge. This solution constructs a microscale boiling pool structure within the chip packaging layer or heat sink. The working fluid boils and vaporizes within this tiny cavity under the influence of the chip's heat source, absorbing a significant amount of heat. It then condenses back into a liquid state and flows back, forming a highly efficient closed-loop heat dissipation system. This solution boasts low thermal resistance and a high heat transfer coefficient, effectively controlling the chip's operating temperature within a safe range. This ensures the continuous and reliable operation of electronic devices such as 5G base stations, high-performance computers, and AI servers, injecting a "cool" driving force into the development of cutting-edge technologies in the digital age.

[0003] Current research indicates that porous structures significantly increase the effective surface area for heat transfer. Their intricate internal structure, with its crisscrossing pores, provides a considerable number of tiny surface areas per unit volume compared to smooth surfaces. When a liquid boils within a porous structure, bubbles are generated on the walls of these abundant pores. These numerous pores act like tiny "boiling points," allowing the vaporization process to unfold simultaneously over a larger area. Therefore, how to effectively enhance the boiling heat transfer process using porous structures has become a hot research topic in the field.

[0004] Existing patent solutions for structures that enhance heat dissipation have been disclosed. For example, patent publication number CN110842202A, published on February 28, 2020, entitled "A Free Particle / Porous Media Composite Enhanced Boiling Structure and Its Preparation Method," describes a porous matrix structure with several pores containing movable free particles. This application utilizes the enhanced characteristics of nucleation point activation and liquid supply from the wick to nucleation sites during boiling heat transfer to separate bubble nucleation and liquid supply, preventing bubble coalescence and reducing liquid backflow resistance. Simultaneously, it leverages the collision of free particles during boiling to enhance heat conduction, micro-layer evaporation, and convective heat transfer within the working fluid, facilitating bubble nucleation, rapid growth, and high detachment frequency, thus achieving enhanced boiling heat transfer. However, this design cannot address the issue of film boiling under high heat flux. Film boiling, forming a drying zone on the heating surface, significantly reduces the effectiveness of boiling heat transfer. Summary of the Invention

[0005] 1. The technical problem that the invention aims to solve

[0006] The purpose of this invention is to overcome the problem of film boiling that easily occurs in the process of enhancing heat dissipation using porous particle structures in the prior art, and to provide a high-efficiency passive heat dissipation system based on particle movement, which can effectively enhance the boiling heat transfer effect.

[0007] 2. Technical Solution

[0008] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0009] A high-efficiency passive heat dissipation system based on particle movement includes a boiling pool, pipes, and a condenser. The boiling pool is filled with a fluid medium, and the bottom wall of the boiling pool has a heat-conducting layer for transferring heat from a heat source into the boiling pool. Movable particles are laid inside the boiling pool. The inlet and outlet of the pipes are connected to the inner cavity of the boiling pool, and a condenser is provided on the outside of the pipes.

[0010] Furthermore, the surface of the movable particles has a hydrophilic porous liquid storage structure.

[0011] Furthermore, the movable particles include a microparticle framework and multiple microparticle pores formed on the surface of the microparticle framework.

[0012] Furthermore, the microparticle skeleton of the movable particle has a hollow microparticle in the middle, and the microparticle pores on the surface are connected to the hollow microparticle in the center.

[0013] Furthermore, the movable particles are metal microparticles, and the thermal conductivity of the metal microparticles is not less than 20 W / (m·K).

[0014] Furthermore, a partition net is provided on the bottom wall of the boiling tank, which evenly divides the bottom of the boiling tank into multiple placement areas, and movable particles are respectively laid in each placement area.

[0015] Furthermore, particle barrier nets are installed at the inlet and outlet of the pipes on the boiling tank. These particle barrier nets can restrict movable particles in the boiling tank from entering the pipes.

[0016] Furthermore, the particle size of the movable particles is 5–250 μm.

[0017] Furthermore, the thermal conductivity of the heat-conducting layer is not less than 100 W / (m·K).

[0018] Furthermore, the liquid level of the fluid medium in the boiling tank is lower than the height of the inner cavity of the boiling tank, and the inlet and outlet positions of the pipes connecting to the boiling tank are all below the liquid level of the fluid medium.

[0019] This invention utilizes movable particles arranged at the bottom of a boiling tank to promote and enhance heat transfer during the formation and development of boiling heat transfer. Simultaneously, the particle movement strengthens flow field disturbance and enhances boiling. The system uses the kinetic energy of phase change steam to drive the circulation of the working fluid within the system, achieving passive heat dissipation. The microparticles contain a hydrophilic porous structure, maintaining a liquid-wetted state during boiling phase change heat transfer, ensuring adhesion and migration to the phase change interface during boiling. The movable particles provide vaporization nuclei for the boiling zone at the heat source point within the boiling tank and carry heat into the flow... The porous particles enhance boiling heat transfer by creating a solid volume. Furthermore, their movement disturbs the fluid within the boiling pool, and their fall carries liquid back to the heating surface for boiling. When they collide with large bubbles, they accelerate bubble detachment. Under high heat flux, the fall of porous particles also disrupts the vapor film formed on the heating surface, causing the carried liquid to boil again. This mitigates localized hot spots in the drying zone, accelerates bubble detachment, and delays vapor film formation. Simultaneously, the arrangement of movable particles increases the temperature of the fluid zone, achieving continuous boiling.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0022] The heat dissipation system of this invention lays multiple layers of movable particles on the bottom wall of the boiling pool, causing heat to accumulate near the particle layer, resulting in faster boiling of the liquid there. This also promotes the preferential formation of vaporization nuclei in the pits and pores between particles and between particles and the boiling pool. Simultaneously, the hydrophilic porous structure of the movable particles maintains a wetted state of the liquid during the boiling phase change heat transfer process, ensuring adhesion and migration to the phase change interface during boiling. Furthermore, due to the excellent thermal conductivity of the movable particles, heat is conducted not only from the bottom micro-liquid layer and nearby superheated liquid to the bubbles, but also from surrounding particles to the bubbles. When particles move and come into contact with bubbles, they transfer the adsorbed heat to the bubbles, enhancing the bubble growth rate. When particles bounce up and down, the impact of the particles causes the bubbles to break, accelerating bubble detachment. Moreover, when particles fall, they bring tiny cold fluids into the superheated fluid, accelerating the detachment of large surface bubble bags and disrupting the vapor film that degrades heat transfer under high surface heat flux, thereby enhancing the overall boiling heat transfer effect of the device and improving its heat transfer capacity. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the heat dissipation system of the present invention;

[0024] Figure 2 This is a schematic diagram of the porous microparticle structure in this invention;

[0025] (a) is the cross-sectional structure of porous microparticles, (b) is the cross-sectional structure of hollow microparticles, and (c) is the surface porous structure of microparticles.

[0026] Figure 3 This is a schematic diagram of bubble nucleation in the present invention;

[0027] Figure 4 This is a schematic diagram of bubble growth in the present invention;

[0028] Figure 4 In this context, q1 represents the heat transferred from the particles to the bubbles, and q2 represents the heat transferred from the bottom of the boiling tank.

[0029] Figure 5 This is a schematic diagram of bubble detachment in the present invention;

[0030] Figure 6 This is a schematic diagram of particle impacting bubbles in this invention;

[0031] Figure 7 This is a top view showing the change and migration of hot spots on the heated wall surface in this invention.

[0032] Explanation of the labels in the diagram:

[0033] 1. Boiling tank; 2. Movable particles; 21. Microparticle skeleton; 22. Porous microparticles; 23. Hollow part of microparticles;

[0034] 3. Heat-conducting layer; 4. Heat source; 5. Pipe; 6. Condenser; 7. Bubble. Detailed Implementation

[0035] To further understand the content of this invention, a detailed description of the invention will be provided in conjunction with the accompanying drawings.

[0036] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] The present invention will be further described below with reference to embodiments.

[0038] Example

[0039] Combination Figures 1-7As shown, this embodiment provides a high-efficiency passive heat dissipation system based on particle movement, including a boiling pool 1, a pipe 5, and a condenser 6. The boiling pool 1 is filled with a fluid medium, such as water, methanol, ethanol, or Freon. The bottom wall of the boiling pool 1 has a heat-conducting layer 3 for transferring heat from the heat source 4. The heat-conducting layer 3 is used to transfer heat from the heat source 4 into the boiling pool 1. In practice, it is preferable to directly use the bottom wall of the boiling pool 1 as the heat-conducting layer 3, receiving and transferring heat through the bottom wall of the boiling pool 1. Movable particles 2 are laid inside the boiling pool 1. The inlet and outlet of the pipe 5 are respectively connected to the inner cavity of the boiling pool 1, and the condenser 6 is provided on the outside of the pipe 5. (See attached diagram.) Figure 1 This system is used to quickly dissipate heat generated by heat source 4. In practice, heat source 4 can be a single group or multiple groups, or can be randomly distributed, etc. The heat is conducted to the boiling pool 1 through the heat-conducting layer 3.

[0040] In practice, the movable particles 2 are metal microparticles with a thermal conductivity of not less than 20 W / (m·K), preferably made of materials such as copper or aluminum. The particle size of the movable particles 2 is 5–250 μm. Furthermore, the thermally conductive layer 3 is also preferably made of a material with high thermal conductivity, with a thermal conductivity of not less than 100 W / (m·K), preferably made of materials such as copper or aluminum.

[0041] Combination Figure 2 As shown, in this embodiment, the surface of the movable particle 2 has a hydrophilic porous liquid storage structure, ensuring liquid wetting to provide continuous particle surface boiling, and allowing free movement during boiling heat transfer. Specifically, the movable particle 2 includes a microparticle framework 21 and multiple microparticle pores 22 formed on the surface of the microparticle framework 21. More preferably, a microparticle hollow portion 23 is formed in the center of the microparticle framework 21 of the movable particle 2, and the surface microparticle pores 22 are connected to the central microparticle hollow portion 23 to further enhance the liquid storage capacity. These surface porous structures help enhance the liquid storage capacity of the movable particle 2 and ensure the wetting of the movable particle 2 to achieve the migration effect of the gas-liquid interface. In addition, while increasing the vaporization core for boiling heat transfer, it is beneficial for reboiling bubbles to drive their free movement in the liquid working medium to further enhance heat transfer.

[0042] In practice, the amount of movable particles 2 should be at least 2-5 layers covering the heating surface, such as 2-5 layers covering the bottom wall of the boiling tank 1. Furthermore, the movement range of the movable particles 2 can be constrained by a frame, and the size of the subdivided areas can be further refined to achieve more precise constraint on the movable particles 2. For example, in this embodiment, a dividing net is preferably provided on the bottom wall of the boiling tank 1, and the dividing net evenly divides the bottom of the boiling tank 1 into multiple placement areas, with the movable particles 2 laid in each placement area. (The last sentence appears to be incomplete and possibly refers to a different embodiment.) Figure 7As shown, the separator can be evenly divided into nine spaces on the bottom wall of the boiling tank 1, which makes it easy for the movable particles 2 to be distributed in each area. By using the jumping of the particles, heat is quickly carried into the fluid to enhance boiling heat transfer. When the particles fall back to the heating surface and collide with the bubbles, the bubbles are accelerated to detach. It can also destroy the vapor film formed under the high heat flow and delay the occurrence of film boiling that deteriorates heat transfer.

[0043] Furthermore, to prevent movable particles 2 from entering the pipe 5, particle barrier nets are installed on the boiling tank 1 at the inlet and outlet positions of the pipe 5. The particle barrier nets can restrict movable particles 2 in the boiling tank 1 from entering the interior of the pipe 5. In addition, the liquid level of the fluid medium in the boiling tank 1 is lower than the height of the inner cavity of the boiling tank 1, and the outlet and inlet positions of the pipe 5 connecting to the boiling tank 1 are both below the liquid level of the fluid medium.

[0044] The purpose of this embodiment is to provide a high-efficiency phase change heat dissipation system. In this system, the phase change component transfers heat to the boiling pool 1 through a heat-conducting layer 3. In the depressions between movable particles 2 and between movable particles 2 and the boiling pool 1, the pores preferentially serve as active vaporization nucleation sites, which is more conducive to the generation of vaporization nuclei. Simultaneously, due to the good thermal conductivity of the movable particles 2, heat is conducted not only from the bottom micro-liquid layer and nearby superheated liquid to the bubbles 7, but also from the surrounding movable particles 2 to the bubbles 7. When the movable particles 2 move and come into contact with the bubbles 7, they transfer the adsorbed heat to the bubbles 7, enhancing the growth rate of the bubbles 7. When the movable particles 2 bounce up and down, the impact of the movable particles 2 causes the bubbles 7 to break, accelerating the detachment of the bubbles 7. The continuous movement of the movable particles 2 within the boiling pool 1 allows for a more uniform distribution of heat throughout the pool, avoiding overheating caused by localized heat accumulation. Moreover, the movable particles 2 form a porous structure between the movable particles 2 and the bubbles 7, which enhances the porous phase change effect. When the liquid is heated and boils to generate bubbles 7, these movable particles 2 will move around with the convection of the liquid and the rising and breaking of the bubbles 7. Their movement will drive the surrounding liquid to flow together, which will enhance the boiling heat transfer in the bottom liquid area.

[0045] The following combination Figures 3-7 The heat dissipation system of this embodiment is described in detail below:

[0046] Figure 3 , 4 Figure 5 shows a schematic diagram of bubble nucleation, growth, and detachment. Figure 1The diagram shows the working state of the heat dissipation system. When heat source 4 is cooled, heat is rapidly transferred to boiling pool 1 through heat-conducting layer 3. Due to the increased heat, a thin fluid layer with drastic temperature changes exists near the heating surface. The movable particles 2 create a porous structure between the particles and bubbles, enhancing the porous phase change effect. Simultaneously, the movement and vertical movement of the movable particles 2 strengthen the flow field disturbance within boiling pool 1, enhancing boiling heat transfer in the bottom liquid region. Furthermore, when the movable particles 2 accumulate on the heating surface to form a porous structure, heat accumulates near the particle layer, causing the liquid near the particles to overheat more quickly, thus accelerating the boiling rate. Heat is not only conducted from the bottom micro-liquid layer and nearby overheated liquid to the bubbles, but also from surrounding particles to the bubbles. When particles come into contact with bubbles during their movement, the particles transfer the adsorbed heat to the bubbles, increasing the bubble growth rate, facilitating bubble detachment, and effectively preventing localized overheating.

[0047] Figure 6 This is a schematic diagram of the impact of movable particle 2 on the bubble. Figure 7 The diagram shows a top view of the hotspot movement on the heated wall surface. Due to the high thermal conductivity of the movable particles 2, the hotspot position migrates as the particles move. Furthermore, because the movable particles 2 move freely, during their vertical movement, they not only disturb the thermal boundary layer and disrupt the vapor film on the heated surface under high heat flux when they collide with it, but also carry cold fluid back to the superheated region, thereby enhancing heat transfer. On the other hand, the arrangement of the movable particles 2 increases the heat transfer area, achieving rapid heat transfer. When steam enters pipe 5, it propels the working fluid to the condenser 6. In the condensation region, the bubbles release heat and then cool and contract, causing a pressure drop. This creates a pressure difference within the flow channel. Combined with the pressure imbalance with adjacent pipes, this causes the working fluid to oscillate randomly between the evaporation and condensation sections, achieving efficient heat transfer through pulsating flow and phase change heat transfer.

[0048] The present invention and its embodiments have been described above illustratively. This description is not restrictive and is merely one embodiment of the present invention, and is not actually limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A high-efficiency passive heat dissipation system based on particle movement, characterized in that: The system includes a boiling tank (1), pipes (5), and a condenser (6). The boiling tank (1) is filled with a fluid medium. The bottom wall of the boiling tank (1) has a heat-conducting layer (3) for transferring heat from the heat source (4). The heat-conducting layer (3) is used to transfer heat from the heat source (4) into the boiling tank (1). Movable particles (2) are laid inside the boiling tank (1). The inlet and outlet of the pipe (5) are connected to the inner cavity of the boiling tank (1), and a condenser (6) is provided on the outside of the pipe (5). The movable particles (2) have a hydrophilic porous liquid storage structure on their surface; A partition net is provided on the bottom wall of the boiling tank (1). The partition net is evenly divided into multiple placement areas at the bottom of the boiling tank (1), and movable particles (2) are laid in each placement area respectively.

2. The high-efficiency passive heat dissipation system based on particle movement according to claim 1, characterized in that: The movable particle (2) includes a microparticle framework (21) and a plurality of microparticle pores (22) formed on the surface of the microparticle framework (21).

3. The high-efficiency passive heat dissipation system based on particle movement according to claim 2, characterized in that: The movable particle (2) has a hollow part (23) formed in the middle of the microparticle skeleton (21), and the microparticle pores (22) on the surface are connected to the hollow part (23) in the center.

4. The high-efficiency passive heat dissipation system based on particle movement according to claim 1, characterized in that: The movable particles (2) are metal microparticles, and the thermal conductivity of the metal microparticles is not less than 20 W / (m·K).

5. A high-efficiency passive heat dissipation system based on particle movement according to any one of claims 1-4, characterized in that: A particle barrier net is provided at the inlet and outlet of the pipe (5) on the boiling tank (1). The particle barrier net can restrict the movable particles (2) in the boiling tank (1) from entering the pipe (5).

6. The high-efficiency passive heat dissipation system based on particle movement according to claim 1, characterized in that: The particle size of the movable particles (2) is 5 ~ 250 μm.

7. The high-efficiency passive heat dissipation system based on particle movement according to claim 1, characterized in that: The thermal conductivity of the thermally conductive layer (3) is not less than 100 W / (m·K).

8. The high-efficiency passive heat dissipation system based on particle movement according to claim 1, characterized in that: The liquid level of the fluid medium in the boiling pool (1) is lower than the height of the inner cavity of the boiling pool (1), and the inlet and outlet positions of the pipe (5) connected to the boiling pool (1) are all below the liquid level of the fluid medium.

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