Aircraft control equipment thermal management device and thermal control method

Abstract

The invention discloses an aircraft control equipment thermal management device and a thermal control method, and belongs to the technical field of aircraft equipment thermal management. The device comprises a soaking unit, a heat storage unit and a pressure relief unit. The heat homogenizing unit conducts heat generated by the aircraft control equipment heating unit into the phase change material in the heat storage unit in a heat transfer mode. The pressure relief unit is located in a shell of the heat storage unit, a dynamic pressure balance method is adopted, the internal pressure of the heat storage unit is adjusted through a piston, and therefore the air pressure dynamic balance problem caused by volume change in the solid-liquid phase change process of the phase change material is solved. The design of soaking and heat storage under the volume constraint of aircraft control equipment is achieved, pressure balance in the heat storage unit is achieved through the pressure relief unit, the heat dissipation and heat storage capacity is effectively improved, and meanwhile safety and reliability can be guaranteed.

Description

Technical Field

[0001] The invention relates to a thermal management device and a thermal control method for aircraft control equipment, belonging to the technical field of thermal management of aircraft equipment. Background Art

[0002] With the increasing demand for integration and miniaturization of aircraft equipment products, the overall power consumption density of the products has increased dramatically, resulting in a harsh thermal environment inside the products. If the heat generated by the long-term operation of the internal electronic devices cannot be removed in time, it will lead to heat accumulation, thus causing thermal failure. In response to this technical problem, Chinese invention patent CN213847341 discloses a pedometer temperature control circuit board for a single-chip microcomputer, in which a heat conducting plate and a plurality of heat sinks are used to dissipate heat from the chip. However, this method relies on air convection to remove heat. Since the aircraft equipment is in a closed fuselage, the air flow speed is slow and the convection heat transfer efficiency is low. Therefore, it is difficult for the heat sink fins to provide sufficient heat dissipation effect under high heat load environment.

[0003] In order to improve the efficiency of thermal management, some existing thermal management devices have introduced phase change materials and sealed them in a metal shell. The heat is transferred from the chip to the phase change material by heat conduction, and a large amount of heat is absorbed and stored during the melting process. For example, Chinese invention patent CN110087438A discloses a heat dissipation and heat storage device for high-power devices in a logging instrument, which transfers the heat of the high-power device to the phase change material through a heat-conducting base and a heat-conducting pipe. However, when this phase change material melts at high temperature, it expands in volume due to the decrease in density, and then squeezes the air in the closed cavity to increase the pressure, which can easily cause leakage of the phase change material. Existing solutions usually add leakage inhibitors to the phase change material. For example, Chinese invention patent CN118085825A discloses a phase change composite material and a preparation method thereof, which mixes a thermally conductive filler with a skeleton carrier to prevent leakage of the phase change material through pore adsorption and hydrogen bonding. However, this type of method has problems such as complex selection and high manufacturing cost, and its effect is not ideal. In addition, due to space limitations of existing equipment, the heat storage unit cannot be directly attached to each module, which also makes it impossible to effectively remove heat.

[0004] Through the above analysis, it can be seen that in the research on thermal management devices, the existing disclosed technologies mainly adopt the heat dissipation fin method based on thermal convection, or the phase change material heat absorption and heat storage method based on thermal conduction. The former relies on air convection heat exchange and has the problem of low efficiency in a high heat load closed environment such as an aircraft, while the latter has the risk of high-pressure leakage caused by the high-temperature expansion of the phase change material, and the existing disclosed technologies usually solve it by adding leakage inhibitors, resulting in high manufacturing costs and unsatisfactory effects, making it difficult for phase change materials to be used in engineering and models in aircraft. The existing disclosed technologies have not proposed an efficient overall thermal management solution for highly integrated and miniaturized aircraft control equipment, and have not fundamentally solved the heat dissipation and phase change material anti-leakage problems in a high heat load environment, and cannot meet the needs of greatly improving the heat dissipation efficiency and reliability of the equipment while taking into account the requirements of system structure, volume weight and cost indicators. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, a thermal management device and a thermal control method for aircraft control equipment are proposed, a heat equalization unit and a heat storage unit are designed under the volume constraint of the aircraft control equipment, and a pressure relief unit is used to achieve internal pressure balance of the heat storage unit, thereby effectively improving the heat dissipation and heat storage capabilities, while ensuring safety and reliability.

[0006] The technical solution of the present invention is:

[0007] A thermal management device for aircraft control equipment comprises a substrate, a heat-saturating unit, a heat storage unit and a pressure relief unit, wherein:

[0008] The substrate is a closed shell, and the inner cavity is used to place the power module and information processing module, heat equalization unit, heat storage unit and pressure relief unit in the aircraft control equipment;

[0009] The heat equalization unit is closely attached to the power module and the heat storage unit, and is used to transfer the heat energy generated by the power module to the heat storage unit;

[0010] The heat storage unit is connected to the information processing module via thermal grease, and the thermal grease transfers the heat energy generated by the information processing module to the heat storage unit; the inner cavity of the heat storage unit encapsulates a phase change material, and the absorbed heat energy causes the phase change material to undergo a solid-liquid phase change;

[0011] The pressure relief unit is interconnected with the heat storage unit, and includes a piston, an elastic member, and a filter. The spring contacts the bottom surface of the piston and is located in the axial direction of the piston. The piston cavity is connected to the inner cavity of the heat storage unit through the filter. The filter is used to prevent the phase change material from flowing into the piston cavity.

[0012] Furthermore, the heat storage unit comprises a heat storage boss, a heat storage shell, a heat storage end cover and a phase change material;

[0013] The heat storage shell and the heat storage end cover are both made of high-temperature resistant titanium alloy, and the two are fixedly connected to form a closed cavity for encapsulating the phase change material;

[0014] A plurality of the heat storage bosses are welded to the upper surface of the heat storage end cover, and each heat storage boss is connected to a chip on the information processing module through thermal conductive silicone grease;

[0015] The phase change material is paraffin, which undergoes solid-liquid changes at high temperatures;

[0016] The heat exchange surface of the heat storage unit includes the contact surfaces of the heat storage boss, the heat storage shell, and the heat storage end cover with the chip, the substrate, and the heat equalizing unit respectively.

[0017] Furthermore, the heat exchange surface of the heat storage unit is processed by coating a graphene coating with a thickness of 1 μm using a chemical vapor deposition method. The graphene purity is not less than 99%, so as to further enhance the thermal conductivity.

[0018] Furthermore, when encapsulating the phase change material, a perfusion hole is drilled on the heat storage end cover, and a high-temperature perfusion process is used to heat the paraffin to 120°C and perfuse it into the closed cavity of the heat storage unit. The perfusion volume fraction is controlled at 80% to 90%. After the perfusion is completed, the perfusion hole is welded and sealed.

[0019] Furthermore, the contact surface between the heat storage shell and the phase change material has a plurality of semi-annular groove structures.

[0020] Furthermore, the heat spreader unit adopts a sandwich design, that is, a high thermal conductivity graphite sheet is sandwiched between two layers of copper alloy; the heat spreader unit structure is designed to be Z-shaped, with the upper and lower end faces tightly fitting with the upper surface of the power module and the lower surface of the heat storage end cover respectively, and the vertical side wall connects the power module and the side of the heat storage shell.

[0021] Furthermore, the method for determining the maximum variable volume required for the piston chamber of the pressure relief unit is:

[0022]

[0023] Where V r is the maximum variable volume of the piston chamber, V i,air 、V i,wax are the initial air volume of the thermal storage unit packaging cavity and the phase change material filling volume respectively; T w , T i , T m are working temperature, initial air temperature, and phase change material filling temperature; β l is the volume expansion coefficient of the liquid phase change material, V i is the packaging volume of the heat storage unit, P i , P max They are the initial pressure of the packaging cavity of the heat storage unit and the maximum pressure of the welding point of the heat storage unit.

[0024] Furthermore, the method for determining the stiffness of the elastic member is:

[0025]

[0026] Where k is the stiffness of the elastic member and A is the area of ​​the piston.

[0027] Furthermore, the filter material is polytetrafluoroethylene, and the pore size of the filter is 0.2 microns.

[0028] A method for thermal control using a thermal management device for aircraft control equipment, comprising:

[0029] S1: Fill the phase change material into the heat storage shell, seal the phase change material in the heat storage shell with a heat storage end cover, and place a filter, an elastic member, and a piston in the hole of the heat storage shell in the axial direction; the hole of the heat storage shell is set at the corner of the heat storage shell and has a cylindrical shape;

[0030] S2: Install the heat storage unit in the base, the information processing module chip and the heat storage boss are tightly fitted through thermal grease, and the power module and the heat storage unit are connected through the heat distribution unit. The heat of the heating unit is transferred to the phase change material in the heat storage unit through heat conduction and stored;

[0031] S3: In the working state, the phase change material and the air in its cavity expand due to the increase in temperature. When the internal pressure exceeds the maximum pressure of the heat storage unit set by the elastic member in the pressure relief unit, the piston opens and the volume of the piston cavity increases, thereby reducing the pressure in the internal cavity of the heat storage unit and preventing the phase change material from leaking at high temperature and high pressure.

[0032] The advantages of the present invention compared with the prior art are:

[0033] (1) The present invention transfers the heat of the heating unit in the aircraft equipment through contact with the heat storage unit, and stores it in the phase change material in the form of heat conduction, which simplifies the heat transfer link and reduces the heat transfer thermal resistance. At the same time, by coating the heat exchange surface of the heat storage shell with a graphene coating, the thermal conductivity efficiency is further enhanced. The present invention has stronger heat dissipation and heat storage capabilities, and can effectively suppress the temperature rise rate of aircraft equipment.

[0034] (2) The present invention designs a Z-shaped heat-averaging unit to achieve flexible connection between the heating unit and the heat storage unit in a limited space, thereby optimizing the heat transfer path. At the same time, a "sandwich" design is adopted to sandwich a high thermal conductivity material between two layers of copper alloy, thereby further enhancing the thermal conductivity of the heat-averaging unit and ensuring uniform and efficient heat transfer.

[0035] (3) The present invention designs a pressure relief unit and adopts a dynamic pressure balance mechanism. The volume of the closed cavity of the heat storage unit is changed by a piston, thereby achieving internal pressure regulation, eliminating the high-pressure leakage problem caused by the high-temperature expansion of the phase change material, reducing the requirements for the welding strength between the heat storage end cover and the heat storage shell, and improving the safety and reliability of the device.

[0036] (4) The present invention adopts module-level thermal management technology, which has a simple and compact structure, is easy to install and disassemble, and occupies a small space. It is suitable for the heat dissipation problem of equipment in narrow spaces such as aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0038] Figure 1 This is an overall schematic diagram of a thermal management device for aircraft equipment according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the structure of a heat storage unit according to an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of a heat soaking unit according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of a pressure relief unit according to an embodiment of the present invention;

[0042] Figure 5 It is a temperature rise curve diagram of the heat dissipation effect of the aircraft equipment according to the embodiment of the present invention. DETAILED DESCRIPTION

[0043] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0044] The present invention provides a thermal management device for aircraft control equipment, comprising a substrate, a heat equalization unit, a heat storage unit and a pressure relief unit.

[0045] The base is connected to the heating unit, the heat absorbing unit, and the heat storage unit, and is used to protect and store various devices and components. The base includes a shell 1 and a cover plate 2. Figure 1 As shown, they are all made of aluminum alloy.

[0046] The heating unit includes a power module 3 and an information processing module 5. The chip 7 in the information processing module 5 is connected to the heat storage boss 6 through thermal grease. The chip 7 transfers heat to the heat storage boss 6 in a heat conduction manner.

[0047] The material of the heat soaking unit 4 is copper alloy, and the structure is designed to be Z-shaped. Figure 3 As shown. The heat-saturating unit 4 adopts a "sandwich" design, that is, a high thermal conductivity graphite sheet is sandwiched between two layers of copper alloy. The two ends of the heat-saturating unit 4 are tightly fitted with the upper surface of the power module 3 and the lower surface of the heat storage end cover 18, respectively, and the middle section of the heat-saturating unit 4 connects the power module 3 and the side of the heat storage shell 8.

[0048] Heat storage unit such as Figure 2 As shown, it includes a heat storage boss 6, a heat storage shell 8, a heat storage end cover 18 and a phase change material 16. The heat storage boss 6 and the upper surface of the heat storage end cover 18 are welded by argon arc welding, and the gap between the heat storage shell 8 and the heat storage end cover 18 is also welded by argon arc welding. The heat storage unit is fastened to the shell 1 through a bolt hole 19. The heat storage shell 8 and the heat storage end cover 18 are made of high-temperature resistant titanium alloy material, and the two form a closed cavity 17 for encapsulating the phase change material 16. The phase change material 16 is paraffin, and the solid density is 0.80g / cm 3 ~0.90g / cm 3 , the melting point is 68℃~72℃, the enthalpy value is ≥240KJ / Kg, and solid-liquid changes occur at high temperatures. When encapsulating the phase change material 16, a perfusion hole is drilled on the heat storage end cover 18, and a high-temperature perfusion process is used to heat the paraffin to 120℃ and perfuse it into the heat storage unit cavity. The perfusion volume fraction is controlled at 80%~90%. After the perfusion is completed, the perfusion hole is welded and sealed. The heat exchange surface of the heat storage unit includes the heat storage boss 6, the heat storage shell 8, the heat storage end cover 18 and the contact surface of the chip 7, the shell 1, and the heat equalization unit 4. The heat exchange surface is processed and coated with a graphene coating by a chemical vapor deposition method. The thickness is 1μm, and the purity of the graphene is not less than 99%, which further enhances the thermal conductivity. Among them, the contact surface between the heat storage shell 8 and the phase change material 16 has multiple semi-annular groove structures, and a hole 12 is opened at the corner of the heat storage shell 8. The shape is a cylindrical tube, and the hole is used to place the pressure relief unit.

[0049] Pressure relief unit such as Figure 4As shown, it includes a filter screen 9, a pressure relief cover 13, a spring 14, a piston 11 and a sealing ring 15. The piston 11 is arranged inside the hole 12 of the heat storage shell 8, the spring 14 contacts the bottom surface of the piston 11 and is located in the axial direction of the piston 11, the pressure relief cover 13 is installed on the top of the hole 12 of the heat storage shell 8 to limit the displacement of the piston 11, the sealing ring 15 realizes the sealing of the hole 12, the piston cavity 10 is connected with the volume cavity of the heat storage shell 8, and the filter screen 9 is arranged in the channel to prevent the phase change material 16 from flowing in. The filter screen 9 is made of polytetrafluoroethylene, the pore size of the filter screen 9 is 0.2 microns, the piston cavity 10 is connected with the closed volume cavity 17, the piston 11 and the pressure relief cover 13 are made of titanium alloy, and the sealing ring 15 is made of high temperature resistant fluororubber.

[0050] The pressure relief air channel is arranged at the top of the heat storage unit and communicates with the piston chamber 10 at the top of the pressure relief unit. At the same time, a filter screen 9 is arranged at the entrance of the piston chamber 10 to prevent the liquid phase change material in the heat storage shell 8 from flowing in at high temperature. The method for determining the maximum variable volume required by the piston chamber 10 is:

[0051]

[0052] Where V r is the maximum variable volume of the piston chamber, V i，air 、V i，wax are the initial air volume of the heat storage unit packaging cavity and the phase change material filling volume, T w , T i , T m They are working temperature, initial air temperature, phase change material filling temperature, β l is the volume expansion coefficient of liquid paraffin, V i is the packaging volume of the heat storage unit, P i , P max They are the initial pressure of the packaging cavity of the heat storage unit and the maximum pressure of the welding point of the heat storage unit.

[0053] The material of the spring 14 is an elastic alloy or other material whose physical and chemical properties change little with temperature. The method for determining the stiffness of the spring 14 is:

[0054]

[0055] Wherein, k is the stiffness of the spring 14, and A is the area of ​​the piston 11.

[0056] The method for thermal control using the thermal management device of aircraft control equipment proposed by the present invention is as follows:

[0057] When the aircraft control device is working, the chip heat of the information processing module 5 is transferred to the heat storage unit by heat conduction through the thermal grease and the heat storage boss 6. The heat of the power module 3 is also transferred to the heat storage unit by heat conduction through the heat equalization unit 4. The phase change material 16 located in the heat storage shell 8 begins to absorb and store heat. As the temperature in the heat storage unit cavity increases, the phase change material 16 and the air begin to expand. When the pressure reaches the maximum pressure that the welding point of the heat storage unit can withstand, the piston 11 in the pressure relief unit moves along the piston cavity 10 to increase the cavity, thereby reducing the internal pressure of the heat storage unit. The present invention reduces the heat transfer link by heat conduction, improves the heat dissipation and heat storage efficiency; adopts a Z-shaped heat equalization unit to optimize the heat conduction path and ensure uniform and efficient heat transfer; at the same time, a pressure relief unit is set to automatically adjust the pressure of the closed cavity 17 of the heat storage unit to achieve pressure balance in the closed cavity 17, prevent high-temperature leakage of the phase change material, and ensure the safety and reliability of the device.

[0058] Figure 5 The temperature rise comparison curve of the phase change material heat storage unit of the present invention and the solid aluminum alloy structural parts with the same external dimensions is reflected when the aircraft equipment works normally for 60 minutes at room temperature. The results show that compared with the solid plate, the temperature of the heat storage unit filled with phase change paraffin wax rises slowly within 60 minutes, and the overall temperature of the heat storage unit is stable at around the phase change point of paraffin wax, with obvious energy storage effect, thus highlighting the effectiveness and superiority of the present invention.

[0059] The above-described embodiments are only preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A thermal management device for aircraft control equipment, characterized in that: It includes a base, a heat-saturating unit, a heat storage unit and a pressure relief unit, wherein: The substrate is a closed shell, and the inner cavity is used to place the power module and information processing module, heat equalization unit, heat storage unit and pressure relief unit in the aircraft control equipment; The heat equalization unit is closely attached to the power module and the heat storage unit, and is used to transfer the heat energy generated by the power module to the heat storage unit; The heat storage unit is connected to the information processing module via thermal grease, and the thermal grease transfers the heat energy generated by the information processing module to the heat storage unit; the inner cavity of the heat storage unit encapsulates a phase change material, and the absorbed heat energy causes the phase change material to undergo a solid-liquid phase change; The pressure relief unit is interconnected with the heat storage unit, and includes a piston, an elastic member, and a filter. The spring contacts the bottom surface of the piston and is located in the axial direction of the piston. The piston cavity is connected to the inner cavity of the heat storage unit through the filter. The filter is used to prevent the phase change material from flowing into the piston cavity.

2. The thermal management device for aircraft control equipment according to claim 1, characterized in that: The heat storage unit comprises a heat storage boss, a heat storage shell, a heat storage end cover and a phase change material; The heat storage shell and the heat storage end cover are both made of high-temperature resistant titanium alloy, and the two are fixedly connected to form a closed cavity for encapsulating the phase change material; A plurality of the heat storage bosses are welded to the upper surface of the heat storage end cover, and each heat storage boss is connected to a chip on the information processing module through thermal conductive silicone grease; The phase change material is paraffin, which undergoes solid-liquid changes at high temperatures; The heat exchange surface of the heat storage unit includes the contact surfaces of the heat storage boss, the heat storage shell, and the heat storage end cover with the chip, the substrate, and the heat equalizing unit respectively.

3. The thermal management device for aircraft control equipment according to claim 2, characterized in that: The heat exchange surface of the heat storage unit is processed and coated with a graphene coating using a chemical vapor deposition method with a thickness of 1 μm and a graphene purity of not less than 99%, further enhancing the thermal conductivity.

4. The aircraft control equipment thermal management device according to claim 2, characterized in that: When encapsulating phase change materials, a perfusion hole is drilled on the heat storage end cover, and a high-temperature perfusion process is used to heat paraffin to 120°C and perfuse it into the closed cavity of the heat storage unit. The perfusion volume fraction is controlled at 80% to 90%. After the perfusion is completed, the perfusion hole is welded and sealed.

5. The thermal management device for aircraft control equipment according to claim 2, characterized in that: The contact surface between the heat storage shell and the phase change material has a plurality of semi-annular groove structures.

6. The thermal management device for aircraft control equipment according to claim 2, characterized in that: The heat spreader unit adopts a sandwich design, that is, a high thermal conductivity graphite sheet is sandwiched between two layers of copper alloy; the heat spreader unit structure is designed to be Z-shaped, with the upper and lower end faces tightly fitting the upper surface of the power module and the lower surface of the heat storage end cover respectively, and the vertical side wall connects the power module and the side of the heat storage shell.

7. The aircraft control equipment thermal management device according to claim 1, characterized in that: The method for determining the maximum variable volume required for the piston chamber of the pressure relief unit is: Where V r is the maximum variable volume of the piston chamber, V i,air 、V i,wax are the initial air volume of the thermal storage unit packaging cavity and the phase change material filling volume respectively; T w , T i , T m are working temperature, initial air temperature, and phase change material filling temperature; β l is the volume expansion coefficient of the liquid phase change material, V i is the packaging volume of the heat storage unit, P i , P max They are the initial pressure of the packaging cavity of the heat storage unit and the maximum pressure of the welding point of the heat storage unit.

8. The thermal management device for aircraft control equipment according to claim 1, characterized in that: The method for determining the stiffness of the elastic member is: Where k is the stiffness of the elastic member and A is the area of ​​the piston.

9. The aircraft control equipment thermal management device according to claim 1, characterized in that: The filter material is polytetrafluoroethylene and the filter pore size is 0.2 microns.

10. A method for thermal control using the thermal management device for aircraft control equipment as claimed in claim 2, characterized in that: include: S1: Fill the phase change material into the heat storage shell, seal the phase change material in the heat storage shell with a heat storage end cover, and place a filter, an elastic member, and a piston in the hole of the heat storage shell in the axial direction; the hole of the heat storage shell is set at the corner of the heat storage shell and has a cylindrical shape; S2: The heat storage unit is installed in the base, the information processing module chip is tightly fitted with the heat storage boss through thermal grease, and the power module is connected with the heat storage unit through a heat-sparing unit; the heat of the heating unit is transferred to the phase change material in the heat storage unit through heat conduction and stored; S3: In the working state, the phase change material and the air in its cavity expand due to the increase in temperature. When the internal pressure exceeds the maximum pressure of the heat storage unit set by the elastic member in the pressure relief unit, the piston opens and the volume of the piston cavity increases, thereby reducing the pressure in the internal cavity of the heat storage unit and preventing the phase change material from leaking at high temperature and high pressure.

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