Active and passive integrated composite cold plate and preparation method thereof

Abstract

The invention relates to an active and passive integrated composite cold plate which comprises a bottom plate, a water channel cavity is formed in one side of the bottom plate, a liquid cooling cover plate is arranged on the water channel cavity to form a liquid cooling plate, a surrounding plate is arranged on the other side of the bottom plate, a grid plate is arranged in the surrounding plate, and notches are formed in the grid plate to form reinforcing partition ribs so that grid spaces can be communicated. A composite phase change material is filled in an area surrounded by the surrounding plate, and an energy storage cover plate is arranged on the surrounding plate to form an energy storage plate; the high-power-consumption seeker has the active and passive heat dissipation capability at the same time, the transient heat dissipation requirement of short-time work and the long-time steady-state heat dissipation requirement of ground debugging are considered, and effective and feasible heat dissipation is carried out on the whole service cycle of the high-power-consumption seeker. Meanwhile, the invention provides an example of the composite cold plate and a preparation method of the composite cold plate, different characteristics of three welding processes of friction stir welding, vacuum brazing and laser welding are comprehensively utilized, welding of different parts is conducted, and finally preparation of the cold plate is completed.

Description

Technical Field

[0001] The present invention belongs to the technical field of active phased array antennas, and particularly relates to a main - passive integrated composite cold plate and a preparation method thereof. Background Art

[0002] The missile - borne seeker with an active phased array antenna system has the characteristics of high transmitting power, compact structure layout, high heat flux density, etc. The sharp increase in heat dissipation makes the internal electronic devices face increasingly severe thermal reliability problems. Usually, the seeker has a short power - on time during flight. In this mode, the problem to be solved is the transient heat dissipation during short - time operation; at the same time, during long - term ground debugging, testing, and maintenance, it needs to be powered on for a long time and frequently. In this mode, the problem to be solved is the steady - state heat dissipation during long - term stable operation. Currently, the common practice is passive heat dissipation by relying on the heat capacity of structural components or the latent heat of phase - change materials during flight mode, and active heat dissipation by introducing an external heat sink such as air cooling or liquid cooling during debugging mode.

[0003] The purpose of the present invention is to solve the problems in the above - mentioned technologies, and provide an integrated composite cold plate that can conduct liquid and store energy through phase change. This cold plate has the ability of both active and passive heat dissipation, taking into account the transient heat dissipation requirements during short - time operation and the steady - state heat dissipation requirements during long - term ground debugging, and effectively and feasibly dissipating heat during the entire service life of a high - power consumption seeker. At the same time, an example of the composite cold plate and its preparation method are provided, comprehensively using the different characteristics of friction stir welding, vacuum brazing, and laser welding processes to complete the welding of different parts, and finally completing the preparation of the cold plate. Summary of the Invention

[0004] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Simplifications or omissions may be made in this part, as well as in the abstract and title of the present application, to avoid obscuring the purpose of this part, the abstract, and the title. However, such simplifications or omissions shall not be used to limit the scope of the present invention.

[0005] In view of the following technical problems in the prior art: Under the requirement of transient heat dissipation during operation, relying solely on the simple means of cooling by the heat capacity of structural components, the heat capacity is limited, and the heat dissipation problem with higher heat dissipation requirements cannot be solved; under the requirement of steady - state heat dissipation during long - term ground debugging, conventional means such as overall air cooling or an outer "water jacket" cannot meet the requirements of high heat dissipation and long working hours, and the temperature at the center of the equipment is often high, and the temperature difference between heat sources at different positions is also large.

[0006] To solve the above - mentioned technical problems, the present invention provides the following technical solutions: A main - passive integrated composite cold plate, comprising,

[0007] A bottom plate, on one side of which a water channel cavity is provided, and a liquid - cooled cover plate is arranged on the water channel cavity to form a liquid - cooled plate.

[0008] On the other side of the bottom plate, a surrounding plate is provided. A grid plate is arranged in the surrounding plate. Notches are formed on the grid plate to form reinforcing partition ribs so that each grid space communicates with each other. The area surrounded by the surrounding plate is filled with a composite phase change material. A storage cover plate is arranged on the surrounding plate to form a storage plate.

[0009] As a preferred technical solution of the active and passive integrated composite cold plate, the composite phase change material uses expanded graphite as the carrier and paraffin as the phase change working medium.

[0010] As a preferred technical solution of the active and passive integrated composite cold plate, two perfusion ports are arranged on the side wall of the surrounding plate, and plugs are arranged at the perfusion ports.

[0011] As a preferred technical solution of the active and passive integrated composite cold plate, the water channel cavity is in an "S" shape and has a rectangular cross-section.

[0012] This application also discloses a preparation method of a main passive integrated composite cold plate based on the foregoing main passive integrated composite cold plate, including

[0013] S1: CNC process an integrated bottom plate with a water channel cavity on one side and a storage cavity on the other side, and the reinforcing partition ribs arranged in the storage cavity;

[0014] S2: Select the friction stir welding process to weld the liquid cooling cover plate;

[0015] S3: Produce expanded graphite

[0016] S4: Weld the storage cover plate by using the vacuum brazing process;

[0017] S5: Pour paraffin into the expanded graphite, and use laser welding to weld the plug at the perfusion port.

[0018] As a preferred technical solution of the preparation method of the active and passive integrated composite cold plate, the friction stir welding process includes selecting a conical stirring head with a needle length of 4 mm, a needle diameter of 2 mm, a root diameter of 4 mm, and a shoulder diameter of 12 mm, a rotation speed of 1000 rpm, a welding speed of 150 - 200 mm / min, and a downward pressure of 0.2 mm for friction welding.

[0019] As a preferred technical solution of the preparation method of the active and passive integrated composite cold plate, the production of expanded graphite includes: putting expanded graphite with a density of 2 - 4 kg / m 3 into the storage cavity of the integrated bottom plate, compressing it at a compression rate of 12 mm / min, and finally obtaining expanded graphite with a density of 100 - 400 kg / m 3 and filling the storage cavity.

[0020] As a preferred technical solution of the preparation method of the active and passive integrated composite cold plate, the welding of the energy storage cover plate includes: selecting an aluminum-magnesium-silicon alloy as the solder, with a welding vacuum of 5×10-3-10-3Pa, rapidly heating the temperature to 400°C in the initial stage of welding and holding for 40 minutes; then heating at a rate of 5-8°C / min to 540°C and holding for 30 minutes, ensuring that the temperature difference in the furnace is <±10°C in this stage; then heating at a rate of 5°C / min to 610°C and holding for 5-10 minutes, ensuring that the temperature difference in the furnace is <±5°C in this stage; then stop heating and cool with the furnace.

[0021] As a preferred technical solution of the preparation method of the active and passive integrated composite cold plate, at an ambient temperature of 85°C, the paraffin is filled and poured by means of liquefied perfusion, with a theoretical filling rate of 100%. When pouring, any one of the pouring ports is selected, and the other pouring port is used as an exhaust hole.

[0022] As a preferred technical solution of the preparation method of the active and passive integrated composite cold plate, the laser welding of the plug includes using argon and nitrogen as protective gases, with an air flow range of 10-20L / min, selecting the continuous laser welding mode for the welding mode, selecting 2kW for the welding power, selecting 40mm / s for the welding speed, and tilting the laser welding head by 5°.

[0023] Advantages of the present invention: The present invention provides an integrated composite cold plate that can conduct liquid and has phase change energy storage. This cold plate has the capabilities of both active and passive heat dissipation, taking into account the transient heat dissipation requirements during short-time operation and the steady-state heat dissipation requirements during long-time ground debugging, and effectively and feasibly dissipating heat during the entire service life of a high-power seeker. At the same time, an example of the composite cold plate and its preparation method are provided, comprehensively applying the different characteristics of three welding processes, namely friction stir welding, vacuum brazing, and laser welding, for welding different parts, and finally completing the preparation of the cold plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0025] Figure 1 is a three-dimensional sectional structure schematic diagram of the present invention;

[0026] Figure 2 is a schematic diagram of the overall side structure of the present invention;

[0027] Figure 3 is a schematic diagram of the structure of the water channel cavity in the present invention;

[0028] Figure 4 It is a schematic flow diagram of the method in the present invention;

[0029] Figure 5 It is the thermal simulation result of the present invention.

[0030] Reference numerals: liquid cooling cover plate 102, bottom plate 100, notch 104, reinforcing partition rib 105, energy storage cover plate 107, composite phase change material 106, expanded graphite 106a, paraffin 106b, enclosing plate 103, filling port 103a, plug 103b, water channel cavity 101, liquid cooling plate area 1, energy storage plate area 2. Specific embodiments

[0031] To make the above objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings of the specification.

[0032] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0033] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The "in one embodiment" that appears in different places in this specification does not all refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0034] Furthermore, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally not in accordance with the general scale, and the schematic diagrams are only examples and should not limit the scope of protection of the present invention herein. In addition, in actual production, three-dimensional spatial dimensions including length, width and depth should be included.

[0035] Embodiment 1

[0036] Referring to Figures 1 to 3 , this embodiment provides a main-passive integrated composite cold plate, including

[0037] A bottom plate 100, a water channel cavity 101 is arranged on one side of the bottom plate 100, a liquid cooling cover plate 102 is arranged on the water channel cavity 101 to form a liquid cooling plate, a surrounding plate 103 is arranged on the other side of the bottom plate 100, a grid plate is arranged in the surrounding plate 103, and a notch 104 is arranged on the grid plate to form a reinforcing partition rib 105 to make each grid space communicate with each other. The area surrounded by the surrounding plate 103 is filled with a composite phase change material 106, and an energy storage cover plate 107 is arranged on the surrounding plate 103 to form an energy storage plate.

[0038] The area enclosed by the enclosure 103 is the energy storage chamber. Figure 2 As shown, the bottom plate 100 , the filled composite phase change material 106 , and the energy storage cover plate 107 together constitute the energy storage plate area 2 , the heat source contacts one side of the energy storage cover plate 107 through the heat conductive member, and the bottom plate 100 and the water channel cavity 101 together constitute the liquid cooling plate area 1 .

[0039] In test mode, active liquid cooling is adopted. Liquid is passed through the liquid cooling plate, and the heat is fully exchanged with the liquid cooling medium and then discharged through the liquid cooling medium. In flight mode, transient passive phase change heat storage is adopted. Heat is absorbed through the latent heat of the built-in phase change medium, and the heat source is controlled within the allowable temperature range during a short working time.

[0040] The composite phase change material 106 uses expanded graphite 106a as a carrier and paraffin 106b as a phase change medium.

[0041] Two pouring ports 103a are provided on the side wall of the enclosure 103, and plugs 103b are provided at the pouring ports 103a.

[0042] The water channel cavity 101 is "S"-shaped and has a rectangular cross section.

[0043] An active-passive integrated composite cold plate comprises: a liquid cooling plate and an energy storage plate, wherein the liquid cooling plate realizes active heat dissipation, and the energy storage plate realizes passive heat dissipation.

[0044] The liquid cooling plate includes a liquid cooling plate package and a water channel cavity 101 arranged therein. The liquid cooling plate package is usually made of metal materials with high thermal conductivity and good comprehensive mechanical properties, such as aluminum-magnesium alloy, aluminum-silicon alloy, aluminum-copper alloy, pure copper, copper alloy, titanium alloy, etc., and is formed by reasonably selecting brazing, diffusion welding, stir friction welding, argon arc welding, electron beam welding and other processes to form a closed cavity of a set form inside it, which is used as the water channel cavity 101. The water channel cavity 101 is divided into series and parallel forms according to the specific requirements of heat dissipation.

[0045] The energy storage plate includes an energy storage plate package and an energy storage cavity, as well as a phase change material installed in the energy storage cavity. The energy storage plate package is similar to the liquid cooling plate package molding method. Usually, the corresponding welding process is selected according to different metal materials, and a closed energy storage cavity of a set form is formed inside it to install the phase change material. Phase change materials are mainly divided into two categories: inorganic and organic. Inorganic ones have higher phase change enthalpy, higher thermal conductivity, and fixed phase change temperature, but there are phase separation and supercooling phenomena; organic ones have little or no supercooling, but the phase change enthalpy is relatively low, and the thermal conductivity is also low, which limits their use.

[0046] Reference Figure 4, the present invention also discloses a preparation method of the active and passive integrated composite cold plate according to any one of the foregoing claims. S1: Use CNC machining to produce an integrated bottom plate with a water channel cavity on one side and an energy storage cavity on the other side, and the enhanced partition ribs 105 arranged in the energy storage cavity;

[0047] S2: Select the friction stir welding process to weld the 6063 liquid cooling cover plate;

[0048] S3: Produce expanded graphite

[0049] S4: Use the vacuum brazing process to weld the energy storage cover plate;

[0050] S5: Pour paraffin into the expanded graphite, and use laser welding to weld the plug at the pouring port.

[0051] Specifically,

[0052] S1: Fabrication of the integrated bottom plate 100: To streamline the heat transfer path, reduce the conduction thermal resistance and the temperature rise caused by the thermal resistance, and at the same time reduce the cold plate profile height and weight to improve the product integration, the water channel cavity 101 and the energy storage cavity are integrated on one structural plate for integrated design. Select 6063 aluminum alloy and use CNC machining to produce the integrated bottom plate 100 with a water channel cavity 101 on one side and an energy storage cavity on the other side. The water channel cavity 101 adopts a rectangular cross-section "S-shaped" path to minimize the flow resistance and improve the temperature uniformity; the energy storage cavity integrates a grid-shaped enhanced partition rib 105, which on the one hand plays the role of enhancing heat conduction and temperature uniformity, and on the other hand improves the mechanical properties of the integrated bottom plate 100, making it have good anti-vibration and anti-impact capabilities; several specifications of notches 104 are opened on the enhanced partition rib 105 to connect each grid in space, so that the liquid paraffin can flow fully during pouring to avoid local "cavity" phenomena; two pouring ports 103a are also opened on one side of the integrated bottom plate 100.

[0053] S2: Welding of the liquid cooling cover plate: The requirements for the water channel cavity are high dimensional accuracy and no leakage under long-term impact and vibration conditions. Therefore, the welded joint of the liquid cooling cover plate not only requires reliable connection but also has high strength indicators. Friction stir welding is a solid-phase connection technology with small welding deformation, good welding joint quality, and high welding strength. Therefore, the friction stir welding process is selected to weld the 6063 liquid cooling cover plate. Select a conical stirring head with a needle length of 4 mm, a needle diameter of 2 mm, a root diameter of 4 mm, and a shoulder diameter of 12 mm, a rotation speed of 1000 rpm, a welding speed of 150 - 200 mm / min, and a downward pressure of 0.2 mm for friction welding.

[0054] S3: Preparation of expanded graphite: In order to solve the shortcomings of single organic phase change materials, this example uses composite phase change materials, that is, expanded graphite as a carrier and paraffin as a phase change medium. The composite phase change material composed of the two has the original advantages of organic phase change materials and increases the thermal conductivity by an order of magnitude. 3 The expanded graphite is placed in the energy storage cavity of the integrated bottom plate and compressed at a compression rate of 12 mm / min to obtain a density of 100-400 kg / m 3 of expanded graphite and fill the energy storage cavity.

[0055] S4: Welding of energy storage cover: The energy storage cover is a flat weld, and reliable welding and small deformation after welding are required. Therefore, a mature vacuum brazing process is used to weld the 3A21 energy storage cover. Before welding, the surface of the parts is cleaned to remove the surface oxide film and oil stains. The solder is selected as Al80Si4Mg6, an aluminum-magnesium-silicon alloy with low melting point and good fluidity. The welding vacuum is 5×10-3-10-3Pa. In the initial stage of welding, the temperature is quickly heated to 400℃ and kept warm for 40min; then heated to 540℃ at a rate of 5-8℃ / min and kept warm for 30min. During this stage, the temperature difference in the furnace is guaranteed to be <±10℃; then heated to 610℃ at a rate of 5℃ / min and kept warm for 5-10min. During this stage, the temperature difference in the furnace is guaranteed to be <±5℃; then stop heating and cool with the furnace.

[0056] S5: Paraffin filling: At an ambient temperature of 85°C, the paraffin is filled and filled by liquefied filling. The theoretical filling rate is 100%. When filling, one filling port is selected, and the other filling port also serves as an exhaust hole.

[0057] S6: Welding of plugs: The injection port is on the side of the integrated base plate, which is difficult to perform contact processing. In addition, the paraffin is still in liquid during this process, which requires small thermal deformation, no mechanical stress and deformation. Laser welding is an efficient and precise welding method that uses a focused laser beam with high energy density as a welding heat source. As a non-contact welding, there is no mechanical stress and mechanical deformation. Since the spot size is small after laser focusing, its heat-affected zone is also small, which is suitable for welding plugs made of 4A11 material. Argon and a small amount of nitrogen are used as protective gases during welding. The gas flow range is 10-20L / min. The continuous laser welding mode is selected for the welding mode, the welding power is selected for 2kW, and the welding speed is selected for 40mm / s. Since aluminum alloy has high reflectivity to lasers, in order to prevent the laser from being burned by light, the laser welding head is tilted 5°.

[0058] Example usage effect: refer to Figure 5Simulation diagram. In flight mode, the latent heat of the composite phase change material is used for passive heat storage to control the heat source temperature between 79.9 - 82.7 °C, meeting the requirement that the maximum temperature of the heat source < 85 °C and the temperature difference < ±3 °C. In test mode, active liquid cooling is carried out by passing liquid through the cold plate to control the heat source temperature between 65.55 - 70.79 °C, meeting the requirement that the maximum temperature of the heat source < 85 °C and the temperature difference < ±3 °C.

[0059] The present invention provides an integrated composite cold plate that can pass liquid and has phase change energy storage. This cold plate has the ability of both active and passive heat dissipation, taking into account the transient heat dissipation requirements during short-term operation and the steady-state heat dissipation requirements during long-term ground debugging, and effectively and feasibly dissipating heat throughout the entire service life of a high-power seeker. At the same time, an example of the composite cold plate and its preparation method are provided. By comprehensively applying the different characteristics of three welding processes, namely friction stir welding, vacuum brazing, and laser welding, welding is carried out on different parts, and finally the preparation of the cold plate is completed.

[0060] The key technical points of the present invention are as follows: the cold plate contains a phase change material and can pass liquid; the cold plate has the ability of both active and passive heat dissipation; the cold plate adopts an integrated design; at the same time, an example of the composite cold plate and its preparation method are provided, and three welding processes, namely friction stir welding, vacuum brazing, and laser welding, are comprehensively used to complete the preparation of the cold plate.

[0061] It should be understood that in the development process of any actual implementation, such as in any engineering or design project, a large number of specific implementation decisions can be made. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, without excessive experimentation, such development efforts will be a routine task of design, manufacturing, and production.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. An active and passive integrated composite cold plate, characterized in that: include, A bottom plate (100), wherein a water channel cavity (101) is provided on one side of the bottom plate (100), and a liquid cooling cover plate (102) is provided on the water channel cavity (101) to form a liquid cooling plate. A panel (103) is provided on the other side of the bottom plate (100), a grid plate is provided in the panel (103), a notch (104) is provided on the grid plate to form a reinforcement rib (105) so that each grid space is connected, the area enclosed by the panel (103) is filled with a composite phase change material (106), and an energy storage cover plate (107) is provided on the panel (103) to form an energy storage plate.

2. The active and passive integrated composite cold plate according to claim 1, characterized in that: The composite phase change material (106) uses expanded graphite (106a) as a carrier and paraffin (106b) as a phase change working fluid.

3. The active and passive integrated composite cold plate according to claim 2, characterized in that: The side wall of the enclosure (103) is provided with two pouring ports (103a), and plugs (103b) are provided at the pouring ports (103a).

4. The active and passive integrated composite cold plate according to claim 3, characterized in that: The water channel cavity (101) is S-shaped and has a rectangular cross section.

5. A method for preparing the active-passive integrated composite cold plate according to any one of claims 1 to 4, characterized in that: S1: CNC processes an integrated bottom plate having a water channel cavity on one side and an energy storage cavity on the other side, and a reinforcing rib (105) disposed in the energy storage cavity; S2: The 6063 liquid cooling cover plate is welded by using the friction stir welding process; S3: Filling and making expanded graphite; S4: welding the energy storage cover plate using vacuum brazing process; S5: Pour paraffin wax into the expanded graphite, and weld the plug to the pouring port by laser welding.

6. The method for preparing the active-passive integrated composite cold plate according to claim 5, characterized in that: The friction stir welding process includes selecting a conical stirring head with a needle length of 4 mm, a needle diameter of 2 mm, a root diameter of 4 mm, and a shoulder diameter of 12 mm, a rotation speed of 1000 rpm, a welding speed of 150-200 mm / min, and a downward pressure of 0.2 mm for friction welding.

7. The method for preparing the active-passive integrated composite cold plate according to claim 6, characterized in that: The method for preparing expanded graphite comprises: preparing expanded graphite having a density of 2-4 kg / m 3 The expanded graphite is placed in the energy storage cavity of the integrated bottom plate and compressed at a compression rate of 12 mm / min to obtain a density of 100-400 kg / m 3 of expanded graphite and fill the energy storage cavity.

8. The method for preparing the active-passive integrated composite cold plate according to claim 7, characterized in that: The welding of the energy storage cover plate includes: selecting aluminum-magnesium-silicon alloy as solder, welding vacuum degree 5×10-3-10-3Pa, rapidly heating the temperature to 400°C and keeping it warm for 40min in the initial stage of welding; then heating to 540°C at a rate of 5-8°C / min and keeping it warm for 30min, during which the temperature difference in the furnace is ensured to be <±10°C; then heating to 610°C at a rate of 5°C / min and keeping it warm for 5-10min, during which the temperature difference in the furnace is ensured to be <±5°C; then stopping heating and cooling with the furnace.

9. The method for preparing the active-passive integrated composite cold plate according to claim 8, characterized in that: At an ambient temperature of 85°C, the paraffin is filled and perfused by means of liquefied perfusion, with a theoretical filling rate of 100%. During perfusion, one perfusion port is selected, and the other perfusion port also serves as an exhaust hole.

10. The method for preparing the active-passive integrated composite cold plate according to claim 9, characterized in that: The laser welding of the plug includes using argon and nitrogen as protective gases, the gas flow range is 10-20L / min, the welding mode selects the continuous laser welding mode, the welding power selects 2kW, the welding speed selects 40mm / s, and the laser welding head is tilted 5°.

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