Measuring device for heat conductivity coefficient of cable

Abstract

The invention relates to the field of spacecraft heat control, and provides a cable heat conductivity coefficient measuring device which comprises a hanging piece, a supporting assembly, a heating belt, a thermocouple, a direct-current power source, a data acquisition instrument, a multi-layer heat insulation assembly and a vacuum heat sink. The hanging piece, the supporting assembly, the heating belt, the thermocouple and the multi-layer heat insulation assembly are all arranged in the vacuum heat sink, one end of the cable is fixed to the hanging piece, and the other end of the cable is fixed to the supporting assembly. The plurality of thermocouples are uniformly arranged on the cable, one end of the cable is circumferentially wound with the heating tape, the outer side of the heating tape is wound with the plurality of layers of heat insulation assemblies, and the direct-current power supply and the data acquisition instrument are electrically connected with the heating tape and the thermocouples respectively. The device is easy to disassemble and assemble, low in cost, suitable for measuring the heat conductivity coefficients of different cables, good in universality and capable of accurately obtaining the heat conductivity coefficients of the cables.

Description

Technical Field

[0001] The present invention relates to the field of spacecraft thermal control, and in particular to a device for measuring the thermal conductivity of a cable. Background Art

[0002] Cables are common components on spacecraft, serving various functions, including power delivery and signal transmission. Cables often have operating temperature limits and must operate at an appropriate temperature. Some cables are located outside the spacecraft cabin, where they are exposed to sunlight and reflections from other components. This heat can occur during operation, posing the risk of exceeding cable temperature limits.

[0003] To ensure that the cable temperature is within the specified range, the cable temperature needs to be simulated. However, the thermal conductivity of the cable is an unknown quantity. The reason is as follows: the cable is a structure composed of multiple layers of materials. Generally speaking, the cross-section of the cable is circular, with the center layer being the inner conductor, the outer layer being the dielectric layer, the outer layer being the outer conductor layer, and the outermost layer being the sheath layer. Each layer is made of a different material, which may be copper or silver with good thermal conductivity, or non-metallic materials with poor thermal conductivity. Therefore, the thermal conductivity of the cable is affected by the combined influence of the thermal conductivity of each layer and the contact derivative coefficient between the layers. In the past, when encountering this problem, the thermal conductivity of the cable was often estimated, which has a large error. Therefore, it is urgent to design a device to measure the thermal conductivity of the cable to solve the above problem. Summary of the Invention

[0004] In view of the defects in the prior art, an object of the present invention is to provide a device for measuring the thermal conductivity of a cable.

[0005] According to the present invention, a device for measuring thermal conductivity of a cable includes a hanger, a support assembly, a heating belt, a thermocouple, a DC power supply, a data acquisition instrument, a multi-layer thermal insulation assembly, and a vacuum heat sink.

[0006] The hanger, support assembly, heating belt, thermocouple, and multi-layer insulation assembly are all arranged inside the vacuum heat sink. The upper end of the hanger is connected to the vacuum heat sink, and the lower end of the hanger is connected to one end of a cable, and the other end of the cable is fixed to the support assembly.

[0007] The plurality of thermocouples are evenly arranged on the cable, the heating tape is wound around one end of the cable close to the hanger, and multiple layers of the thermal insulation assembly are further wound around the outer side of the cable so that the heating tape is not exposed.

[0008] The DC power supply is connected to the heating belt via a cable, and the data acquisition instrument is connected to the thermocouple via a cable.

[0009] Preferably, the support assembly includes a bracket and a tooling plate, the bracket is placed horizontally on the tooling plate, and the other end of the cable is fixed to the top of the bracket.

[0010] Preferably, the tooling plate and the bracket are both made of metal materials.

[0011] Preferably, the tooling plate and the bracket are both made of aluminum alloy 2A12.

[0012] Preferably, the cables are connected via a vacuum flange on the wall of the vacuum heat sink tank.

[0013] Preferably, the heating belt is formed by encapsulating a polyimide film and a constantan wire.

[0014] Preferably, the heating belt winding area accounts for 50% to 80% of the cable surface area.

[0015] Preferably, the multi-layer thermal insulation assembly includes 1 layer of 25 μm polyimide film, 15 layers of double-sided aluminized polyester film, 15 layers of nylon mesh, and 1 layer of 16 μm double-sided aluminized polyester film.

[0016] Preferably, the thermocouple is a T-type thermocouple, which is formed by twisting copper wire and constantan wire into a pair.

[0017] Preferably, the data acquisition instrument is used to convert the original voltage value measured by the thermocouple into a temperature value, and further calculate the thermal conductivity of the cable through the temperature gradient distribution on the cable surface.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention creates a heat source at one end of the cable by wrapping a heating belt around the cable, and the other end of the cable is installed on a bracket as a cold source. Multiple layers of thermal insulation components are wrapped around the surface of the heating belt to prevent the heat from the heat source from directly radiating to the heat sink. When the heating belt is powered, the heat will be transferred from the heat source to the cold source. The temperature distribution on the cable surface during this process is measured by thermocouples, and the thermal conductivity of the cable is further calculated based on the temperature distribution. The present invention is simple to assemble and disassemble, and the required materials are all common materials in the field of spacecraft thermal control. It has low cost and can be applied to the measurement of thermal conductivity of different cables. It has good versatility and can accurately obtain the thermal conductivity of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0021] Figure 1 is a structural diagram of the measuring device;

[0022] Figure 2 The thermocouple temperature is obtained by measuring a certain type of satellite cable using a measuring device.

[0023] The figure shows:

[0024] 1- Cable;

[0025] 2- hanging parts;

[0026] 3- Bracket;

[0027] 4- tooling board;

[0028] 5- Heating belt;

[0029] 6-Thermocouple;

[0030] 7- DC power supply;

[0031] 8-Data acquisition instrument;

[0032] 9-Multi-layer insulation assembly;

[0033] 10- Vacuum heat sink. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0035] The present invention provides a device for measuring the thermal conductivity of a cable, such as Figure 1 As shown, it includes a hanger 2, a support assembly, a heating belt 5, a thermocouple 6, a DC power supply 7, a data acquisition instrument 8, a multi-layer thermal insulation assembly 9 and a vacuum heat sink 10; the hanger 2, the support assembly, the heating belt 5, the thermocouple 6, and the multi-layer thermal insulation assembly 9 are all arranged inside the vacuum heat sink 10, the upper end of the hanger 2 is connected to the vacuum heat sink 10, the lower end of the hanger 2 is connected to one end of the cable 1, and the other end of the cable 1 is fixed to the support assembly. Multiple thermocouples 6 are evenly arranged on the cable 1, and the heating belt 5 is wrapped circumferentially around one end of the cable 1 near the hanger 2 and the multi-layer thermal insulation assembly 9 is continued to be wrapped around the outside of the cable 1 so that the multi-layer thermal insulation assembly 9 covers the heating belt 5. After the winding is completed, the heating belt 5 is not exposed.

[0036] The support assembly includes a bracket 3 and a tooling plate 4. During installation, the bracket 3 and the tooling plate 4 are first placed in the vacuum heat sink 10. The bracket 3 is placed horizontally on the tooling plate 4, and the other end of the cable 1 is fixed to the top of the bracket 3.

[0037] Thermocouples 6 are arranged on the surface of the cable 1 , and a plurality of thermocouples 6 are pasted on the surface of the cable 1 at equal intervals, that is, the plurality of thermocouples 6 are evenly arranged so that the intervals between two adjacent thermocouples 6 are controlled at the same level.

[0038] like Figure 1 As shown, the DC power supply 7 is connected to the heating belt 5 through a cable, and the cable should be transferred through the vacuum flange on the wall of the vacuum heat sink (10). It is used to power the heating belt 5 and serve as a heat source during testing. The data acquisition instrument 8 is connected to the thermocouple 6 through a cable to convert the original voltage value measured by the thermocouple 6 into a temperature value. The thermal conductivity of the cable 1 can be calculated based on the temperature gradient distribution on the surface of the cable 1. The materials used in the present invention are conventional materials in the field of spacecraft thermal control, with low cost, and the device is simple to operate and disassemble, and can be applied to the measurement of thermal conductivity of different cables.

[0039] Specifically, the tooling plate 4 and the bracket 3 are both made of metal materials. Metal materials have good thermal conductivity and can quickly conduct the heat of the cable 1, thereby acting as a cold source.

[0040] For example, in this embodiment, the tooling plate 4 and the bracket 3 are both made of aluminum alloy 2A12. Aluminum alloy is inexpensive and has good thermal conductivity, and can serve as a cold source for the cable 1 .

[0041] For example, in this embodiment, the heating tape 5 is formed by encapsulating a polyimide film and a constantan wire. The heating tape 5 is a polyimide-constantan wire electric heating tape. When powered by a DC power supply, the constantan wire acts as a resistance wire and generates heat. When powered, the heating tape 5 generates heat, thereby heating the cable 1 and serving as a heat source for the cable 1. It should be noted that when the heating tape 5 is wrapped around the surface of the cable 1, the degree of sparseness should be controlled. The wrapped area of ​​the heating tape 5 should preferably account for between 50% and 80% of the surface area of ​​the cable 1.

[0042] Illustratively, in this embodiment, the multi-layer insulation assembly 9 is composed of one layer of 25 μm polyimide film, 15 layers of double-sided aluminized polyester film, 15 layers of nylon mesh, and one layer of 16 μm double-sided aluminized polyester film.

[0043] For example, in this embodiment, the thermocouple 6 is a T-type thermocouple, and is formed by twisting a pair of copper wire and constantan wire. When the multi-layer insulation assembly 9 is wound around the surface of the heating belt 5, it should be wound in a spiral shape, with the last winding of the multi-layer insulation assembly 9 completely covering the previous winding of the multi-layer insulation assembly 9, so that the heating belt 5 is not exposed.

[0044] In a specific embodiment, the thermal conductivity of the cable 1 is tested using the device proposed by the present invention on a certain satellite model. Figure 2After the test reached thermal equilibrium, the temperature values ​​of the six thermocouples 6 on the surface of the cable 1 were obtained, and the thermal conductivity of the cable 1 was calculated to be 0.11 W / m / K.

[0045] This embodiment can use conventional thermal control materials to build a test device. By wrapping a heating tape 5 around one end of the cable 1 as a heat source, the other end of the cable 1 is mounted on a bracket 3 as a cold source. At the same time, a multi-layer thermal insulation component 9 is wrapped around the surface of the heating tape 5 to prevent the heat from the heat source from directly radiating into the vacuum heat sink 10. When the DC power supply 7 supplies power to the heating tape 5, heat is transferred from the heat source to the cold source, thereby creating a temperature gradient on the surface of the cable 1. The temperature gradient on the surface of the cable 1 is measured by the thermocouple 6, and the thermal conductivity of the cable 1 is thus calculated. This device is easy to disassemble and operate, and the required materials are all common materials in the field of spacecraft thermal control. It is low-cost and can accurately obtain the thermal conductivity of the cable 1.

[0046] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0047] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A device for measuring thermal conductivity of a cable, characterized in that: It includes a hanging part (2), a supporting component, a heating belt (5), a thermocouple (6), a DC power supply (7), a data acquisition device (8), a multi-layer thermal insulation component (9) and a vacuum heat sink (10); The hanger (2), the supporting assembly, the heating belt (5), the thermocouple (6), and the multi-layer thermal insulation assembly (9) are all arranged inside the vacuum heat sink (10); the upper end of the hanger (2) is connected to the vacuum heat sink (10); the lower end of the hanger (2) is connected to one end of the cable (1); and the other end of the cable (1) is fixed to the supporting assembly; A plurality of thermocouples (6) are evenly arranged on the cable (1); the heating belt (5) is wound around the circumference of one end of the cable (1) close to the hanger (2); and multiple layers of the thermal insulation assembly (9) are further wound around the circumference of the cable (1) so that the heating belt (5) is not exposed. The DC power supply (7) is connected to the heating belt (5) via a cable, and the data acquisition instrument (8) is connected to the thermocouple (6) via a cable.

2. The device for measuring thermal conductivity of a cable according to claim 1, characterized in that: The support assembly comprises a bracket (3) and a tooling plate (4), wherein the bracket (3) is placed horizontally on the tooling plate (4), and the other end of the cable (1) is fixed to the top of the bracket (3).

3. The device for measuring thermal conductivity of a cable according to claim 2, characterized in that: The tooling plate (4) and the bracket (3) are both made of metal materials.

4. The device for measuring thermal conductivity of a cable according to claim 3, characterized in that: The tooling plate (4) and the bracket (3) are both made of aluminum alloy 2A12.

5. The device for measuring thermal conductivity of a cable according to claim 1, characterized in that: The cables are connected via a vacuum flange on the tank wall of the vacuum heat sink (10).

6. The device for measuring thermal conductivity of a cable according to claim 1, characterized in that: The heating belt (5) is formed by encapsulating a polyimide film and a constantan wire.

7. The device for measuring thermal conductivity of a cable according to claim 6, characterized in that: The proportion of the heating belt (5) winding area to the cable (1) surface area is controlled between 50% and 80%.

8. The device for measuring thermal conductivity of a cable according to claim 1, characterized in that: The multi-layer heat insulation component (9) comprises one layer of 25 μm polyimide film, 15 layers of double-sided aluminized polyester film, 15 layers of nylon wire mesh, and one layer of 16 μm double-sided aluminized polyester film.

9. The device for measuring thermal conductivity of a cable according to claim 1, characterized in that: The thermocouple (6) is a T-type thermocouple, and the thermocouple (6) is formed by twisting copper wire and constantan wire into a pair.

10. The device for measuring thermal conductivity of a cable according to claim 1, characterized in that: The data acquisition instrument (8) is used to convert the original voltage value measured by the thermocouple (6) into a temperature value, and further calculate the thermal conductivity of the cable (1) through the temperature gradient distribution on the surface of the cable (1).

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