Boiling Enhancement Device

Abstract

The present invention discloses a boiling enhancement device that includes an evaporation chamber having an internal cavity and boiling enhancement fins, the boiling enhancement fins being disposed on the inner wall surface of the evaporation chamber, and a phase change heat exchange medium disposed inside the evaporation chamber. The evaporation chamber absorbs heat from a heat source and transfers it to the phase change heat exchange medium through the inner wall surface. The boiling enhancement fins increase the number of vaporization cores on the inner wall of the evaporation chamber and the boiling heat transfer area, thereby accelerating the boiling vaporization of the phase change heat exchange medium and reducing the boiling thermal resistance. The boiling enhancement device of the present invention has the following advantages: The densely arranged boiling enhancement fins maximize the heat exchange area and reduce the boiling heat exchange thermal resistance; the densely distributed holes or windows in the boiling enhancement fins significantly increase the number of bubble nuclei, reducing the diameter of the bubbles and facilitating bubble formation, thereby reducing the thermal resistance of heat exchange.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat exchange devices, and particularly relates to a boiling enhancement device for electronic devices.

Background Art

[0002] Phase change heat dissipation, which is an efficient heat dissipation method, is becoming increasingly popular. Its principle is to utilize the fact that the phase change heat exchange medium boils and vaporizes at a predetermined temperature to absorb heat, and then the gas condenses and liquefies at another position to release heat, thereby transferring heat. It has a high heat transfer effect and is widely applied. The evaporation and vaporization stage is an important stage for phase change heat transfer, and the heat transfer efficiency directly affects the effect of phase change heat transfer.

[0003] In order to improve the heat transfer efficiency and enhance the effect of boiling heat transfer, the principles for enhancing the effect of boiling heat transfer mainly include increasing the number of boiling bubble nuclei, increasing the heat exchange area, and avoiding transition boiling. Among these, the currently mainly used methods for changing the heat transfer surface structure include machining, laser etching, chemical etching method, sintering, etc. By providing trenches, protruding structures, and porous surfaces on the heat transfer surface, the heat exchange area is increased, and the generation of bubble nuclei is increased to achieve the purpose of enhancing boiling heat transfer.

[0004] The machining method has a good effect on the porous surface to be machined, but there is a limit to the increase in the number of bubble nuclei by this method. It is difficult to process pores less than 0.1 mm, and transition boiling is likely to occur with the increase in heat flux, leading to a decrease in heat transfer capacity. Furthermore, the machining method has a high processing cost, a long manufacturing cycle, and is not suitable for efficient mass production.

[0005] Although the metal sintering method can effectively increase the number of bubble nuclei, the sintered pores affect the thermal conductivity of the material and the effective heat exchange area. Also, other substances remain during sintering, affecting the performance of the phase change medium.

[0006] Laser etching and chemical etching methods have drawbacks such as limited etching depth, insufficient heat exchange area, and a high likelihood of transition boiling.

[0007] Therefore, in this field, it is expected that boiling enhancement equipment will be designed that has low thermal resistance for boiling heat transfer, high heat flux for heat transfer, low production costs, and high production efficiency. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] To solve the problems of the above-mentioned prior art, the present invention provides a boiling enhancement device. [Means for solving the problem]

[0009] To achieve the above objective, the technical proposal for the boiling enhancement apparatus of the present invention is specifically as follows.

[0010] A boiling enhancement apparatus comprising an evaporation chamber having an internal cavity and boiling enhancement fins, The boiling-enhancing fins are provided on the inner wall surface of the evaporation chamber, and a phase transition heat exchange medium is provided inside the evaporation chamber. The evaporation chamber absorbs heat from a heat source and transfers it to the phase transition heat exchange medium via the inner wall surface. The boiling-enhancing fins can increase the number of vaporization cores and the area of ​​boiling heat transfer on the inner wall surface of the evaporation chamber, thereby promoting the boiling vaporization of the phase transition heat exchange medium and reducing the boiling thermal resistance.

[0011] Furthermore, the boiling-enhancing fins are a plurality of sawtooth or wavy, elongated heat-dissipating pieces provided on the inner wall surface of the evaporation chamber.

[0012] Furthermore, the long heat dissipation piece is made up of a combination of multiple sawtooth-shaped or corrugated pieces, and in the sawtooth-shaped long heat dissipation piece, the tooth pitch, which is the smallest repeating unit, is less than 1 mm, and the thickness of the sawtooth-shaped piece is less than 0.2 mm.

[0013] Furthermore, among the sawtooth-shaped long heat dissipation pieces, the tooth pitch, which is the smallest repeating unit, is 0.0001 mm to 1 mm, and the thickness of the sawtooth piece is 0.01 mm to 0.2 mm.

[0014] Furthermore, holes or window structures are formed in the boiling-enhancing fins.

[0015] Furthermore, the boiling-enhancing fins are connected to the inner wall of the evaporation chamber by brazing.

[0016] Furthermore, the serrated long heat dissipation piece is a long heat dissipation piece with a triangular serrated or rectangular serrated shape.

[0017] Furthermore, multiple long heat dissipation pieces are arranged parallel to the inner wall surface of the evaporation chamber. The boiling enhancement device further includes an air-cooled heat dissipation unit, in which the channel direction in which multiple elongated heat dissipation pieces are arranged in parallel is perpendicular to the airflow direction of the air-cooled heat dissipation unit.

[0018] Furthermore, the outer wall surface of the evaporation chamber is positioned in contact with the heat source, and the thickness of the side wall of the evaporation chamber in contact with the heat source is less than 2 mm.

[0019] Furthermore, the evaporation chamber has a contact heat-absorbing surface on the outer surface of its side wall, the heat source has a heat source surface, and the contact heat-absorbing surface of the evaporation chamber and the heat source surface of the heat source are in contact. [Effects of the Invention]

[0020] The boiling enhancement apparatus of the present invention has high heat exchange efficiency, low processing costs, and mainly the following advantages. 1) The densely arranged boiling-enhancing fins maximize the heat exchange area and reduce the thermal resistance of boiling heat transfer. 2) The densely distributed pores or windows in the boiling-enhancing fins significantly increase the number of bubble nuclei, i.e., increase the number of boiling nuclei, reduce the diameter of bubbles, make bubble formation easier, and thereby reduce the thermal resistance of heat exchange. 3) The densely provided holes or windows effectively control the size of the bubbles, prevent the formation of a vapor beam, avoid the formation of an unstable vapor film on the wall surface, thereby avoiding transition boiling, increasing the heat flux of boiling heat transfer, and improving the capillary force of the phase change heat exchange medium. 4) The boiling enhancement fins and the evaporation chamber are connected by brazing, thereby reducing the contact thermal resistance between the fins and the evaporation chamber body. 5) Compared with processes such as machining, laser etching, and chemical etching, the brazing process has high processing efficiency, low cost, a mature process, and is suitable for large-scale mass production.

Brief Description of the Drawings

[0021] [Figure 1] It is a perspective view of the boiling enhancement device of the present invention. [Figure 2] It is an enlarged view of the boiling enhancement device of the present invention. [Figure 3] It is a top view of the boiling enhancement device of the present invention. [Figure 4] It is the window structure of the boiling enhancement device of the present invention.

Modes for Carrying Out the Invention

[0022] To better understand the object, structure, and function of the present invention, the boiling enhancement device of the present invention will be described in more detail below with reference to the drawings.

[0023] The related terms of the present invention are interpreted as follows.

[0024] Boiling heat transfer is a heat transfer process in which heat is transferred from the wall surface to the liquid to vaporize the liquid by boiling.

[0025] The vaporization core is a carrier for initiating liquid boiling.

[0026] Thermal conductivity refers to the internal part of an object, with a distance of 1 m and an area of 1 m 2If we take two parallel planes perpendicular to the direction of heat conduction, and the temperature difference between the two planes is 1 K, the heat conducted from one plane to the other in one second is defined as the thermal conductivity of the material, and its unit is watt-meter. -1 Kelvin meters -1 (W·m -1 ·K -1 )

[0027] Thermal resistance is defined as the ratio between the temperature difference at both ends of an object and the power of the heat source when heat is transferred across the object. Its units are Kelvin meters per watt (K / W) or degrees Celsius per watt (°C / W).

[0028] The heat transfer coefficient is the amount of heat transferred per unit time through a unit area when the temperature difference between the air on both sides of a surrounding structure is 1°C (K or °C) under conditions of stable heat transfer, and its unit is watts / m². 2 The formula is (·°C)(W / ·K, where K can be replaced with °C), and it reflects the strength of the heat transfer process.

[0029] Heat flux is defined as the heat transferred per unit area per unit time. The formula is q = Q / (S*t) - Q is heat, t is time, S is the cross-sectional area, and the unit of heat flux is J / (m²). 2 ·s) is

[0030] Transition boiling occurs when, as the heat flux increases, the vapor ejected from a large vaporization core forms a vapor beam. This vapor flow obstructs the liquid being supplied to the heat transfer surface, causing the liquid on the heat transfer surface to dry out quickly, resulting in a rapid increase in the temperature of the heat transfer surface.

[0031] The boiling enhancement apparatus of the present invention includes an evaporation chamber 10 and boiling enhancement fins 20. The evaporation chamber 10 may be a plate-shaped cavity with a central cavity, or it may include a plurality of sub-cavities communicating with each other. The boiling enhancement fins 20 are provided inside the evaporation chamber 10, that is, connected to the inner wall surface of the evaporation chamber 10. The outer surface of the side wall to which the boiling enhancement fins 20 are connected is connected to a heat source and absorbs heat from the heat source. A phase transition heat exchange medium is provided inside the evaporation chamber 10. The phase transition heat exchange medium inside the evaporation chamber 10 absorbs heat from the heat source and boils and vaporizes. Here, the boiling enhancement fins 20 significantly increase the number of boiling vaporization cores on the side wall of the evaporation chamber 10, increase the heat exchange area, and promote the boiling and vaporization of the phase transition heat exchange medium.

[0032] The boiling-enhancing fins 20 are a plurality of elongated sawtooth-shaped or corrugated heat dissipation pieces provided on the inner wall surface of the evaporation chamber 10, for example, triangular sawtooth-shaped or rectangular sawtooth-shaped elongated heat dissipation pieces, or S-shaped corrugated elongated heat dissipation pieces, and extend along a direction perpendicular to the inner surface of the evaporation chamber 10 so that the surface of the boiling-enhancing fins 20 can easily dissipate heat to the outside. The boiling-enhancing fins 20 can be manufactured from materials such as copper, aluminum, copper alloys, aluminum alloys, and stainless steel.

[0033] Multiple sawtooth-shaped elongated heat dissipation pieces are arranged parallel to the inner surface of the side wall of the evaporation chamber 10. When air-cooled heat dissipation is included, the channel direction in which the multiple sawtooth-shaped elongated heat dissipation pieces are arranged is perpendicular to the airflow direction, and the multiple sawtooth-shaped elongated heat dissipation pieces are arranged at equal intervals, thereby ensuring that the fluid flows uniformly through the boiling-enhancing fins 20. The multiple sawtooth-shaped elongated heat dissipation pieces may be arranged offset from each other.

[0034] The sawtooth-shaped elongated heat dissipation piece includes a plurality of sawtooth-shaped fins or corrugated fins, the sawtooth-shaped fins may be triangular-sawtooth or rectangular-sawtooth in shape, for example, the corrugated fins are smoothly transitioning arc-shaped waves, the plurality of sawtooth-shaped and corrugated fins are densely arranged to form a boiling-enhancing structure, the pitch between two adjacent sawtooth pieces (the pitch between the positions of two adjacent corresponding peaks) is less than 1 mm, for example 0.0001 mm to 1 mm, that is, the pitch of the sawtooth, which is the smallest repeating unit, is less than 1 mm, thereby increasing the heat exchange area, the thickness of the sawtooth-shaped or corrugated piece is less than 0.2 mm, for example 0.01 mm to 0.2 mm, and the porosity of the sawtooth-shaped elongated heat dissipation piece is less than 60%, for example 10% to 60%, and the densely arranged sawtooth-shaped or corrugated elongated heat dissipation piece promotes vaporization boiling and reduces the difficulty of subsequent boiling nucleation by being sawtooth-shaped or corrugated.

[0035] Holes or window structures 21 may be formed in the serrated pieces. The holes and window structures 21 can improve heat transfer performance by disrupting the thermal boundary layer, improve the heat exchange coefficient of the boiling-enhanced fins 20, and enhance the heat exchange effect. The shape of the holes may be circular, rectangular, or elliptical, and the shape of the windows may be rectangular, elliptical, or circular. The more holes or windows there are, the higher the heat dissipation effect. The diameter of boiling bubbles can be effectively reduced, that is, the size of the bubbles can be controlled to prevent the formation of steam beams and avoid the occurrence of transition boiling. The holes or window structures formed in the serrated pieces can improve the heat flux of boiling heat transfer and enhance the capillary force of the phase transition heat exchange medium.

[0036] The boiling-strengthening fins 20 are connected to the inner wall surface of the evaporation chamber 10 by brazing, thereby reducing the contact thermal resistance between the boiling-strengthening fins 20 and the evaporation chamber 10, and minimizing the temperature difference between the two. Compared to processes such as micro-machining, laser etching, and chemical etching, the brazing process is simpler, requires less investment in brazing equipment, and offers higher processing efficiency.

[0037] The evaporation chamber 10 is in direct contact with the heat source; that is, the outer surface of the side wall of the evaporation chamber 10 is in direct contact with the heat source, and the outer surface of the evaporation chamber 10 functions as a substitute for the substrate of a conventional heat dissipation device. In this way, the heat transfer efficiency between the heat source and the evaporation chamber 10 is increased. Preferably, the outer wall surface of the evaporation chamber is provided in contact with the heat source, and the thickness of the side wall of the evaporation chamber that is in contact with the heat source is less than 2 mm. The evaporation chamber 10 is preferably a flat plate-like body with a cavity inside, the internal cavity of the evaporation chamber 10 is a flat cavity, and one side wall of the evaporation chamber 10 has a contact heat-absorbing surface. The heat source has a flat heat source surface, and the contact heat-absorbing surface of the evaporation chamber 10 is provided in contact with the heat source surface of the heat source.

[0038] The area of ​​the heat source surface of the heat source is smaller than the area of ​​the contact heat absorption surface of the evaporation chamber 10, and the internal phase transition heat exchange medium can absorb heat from the heat source through phase transition flow and rapidly transfer it along the two-dimensional direction, thereby ensuring temperature uniformity within the evaporation chamber 10.

[0039] In the boiling enhancement apparatus of the present invention, the evaporation chamber 10 directly dissipates heat from the electronic device, the heat source is directly attached to the evaporation chamber 10, the phase transition heat exchange medium is not in contact with the heat source, heat is conducted to the boiling enhancement fins 20 via the side walls of the evaporation chamber 10, and the boiling enhancement fins 20 are in contact with the side walls of the evaporation chamber 10 and the phase transition heat exchange medium.

[0040] As a result, multiple sawtooth-shaped or corrugated long heat dissipation pieces are densely and evenly arranged within the evaporation chamber 10. This structure is advantageous for the generation of a large number of bubble nuclei, which promote the vaporization and boiling of the phase transition heat exchange medium within the evaporation chamber 10. The boiling-enhancing fins 20 promote the conversion of the phase transition heat exchange medium from liquid to gas, and more heat from the heat source is transferred to the phase transition heat exchange medium quickly and uniformly.

[0041] Although the present invention has been described by several embodiments, as is well known to those skilled in the art, various changes and equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, these features and embodiments may be modified based on the present invention to be applicable to specific situations and materials without departing from the spirit and scope of the invention. For this reason, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments that fall within the claims of this application are included within the scope of the invention.

Claims

1. A boiling enhancement apparatus comprising an evaporation chamber having an internal cavity and boiling enhancement fins, The boiling-enhancing fins are provided on the inner wall surface of the evaporation chamber, and a phase transition heat exchange medium is provided inside the evaporation chamber. The evaporation chamber absorbs heat from a heat source and transfers it to the phase transition heat exchange medium via the inner wall surface. The boiling-enhancing fins can increase the area of ​​boiling heat transfer, thereby promoting the boiling vaporization of the phase transition heat exchange medium and reducing the boiling thermal resistance. The boiling-enhancing fin is configured to have a plurality of serrated pieces, The aforementioned serrated segments are densely arranged by simultaneously satisfying the following conditions: The tooth pitch of the sawtooth-like piece is less than 1 mm, the wall thickness of the sawtooth-like piece is less than 0.2 mm, and the porosity of the sawtooth-like piece is 60% or less. Boiling strengthening device.

2. The boiling enhancement apparatus according to claim 1, characterized in that the tooth pitch of the sawtooth piece is 0.0001 mm to 1 mm, and the wall thickness of the sawtooth piece is 0.01 mm to 0.2 mm.

3. The boiling enhancement apparatus according to claim 1, characterized in that holes or window structures are formed in the boiling enhancement fins.

4. The boiling enhancement apparatus according to claim 1, characterized in that the boiling enhancement fins are connected to the inner wall surface of the evaporation chamber by brazing.

5. The boiling enhancement device according to claim 1, characterized in that the boiling enhancement fins have a triangular sawtooth or rectangular sawtooth shape.

6. The boiling enhancement apparatus according to claim 1, characterized in that the outer wall surface of the evaporation chamber is provided in contact with a heat source, and the thickness of the side wall of the evaporation chamber in contact with the heat source is less than 2 mm.

7. The boiling enhancement apparatus according to claim 6, characterized in that the outer surface of the side wall of the evaporation chamber has a contact heat absorption surface, the heat source has a heat source surface, and the contact heat absorption surface of the evaporation chamber and the heat source surface of the heat source are in contact.

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