阅读说明：本技术 超导电缆 (Superconducting cable ) 是由 胡子珩 吴小辰 章彬 汪桢子 汪伟 王哲 林子钊 魏前虎 谭波 马镇威 于 2019-09-24 设计创作，主要内容包括：本申请涉及一种超导电缆。超导电缆包括通电导体、低温杜瓦管、第一流速增强层。低温杜瓦管包围形成容纳腔,通电导体设置于容纳腔内,且容纳腔中灌注有液氮。第一流速增强层覆盖通电导体的外表面,用于增加流经通电导体外表面的液氮的流速。在超导电缆中,通过在通电导体外表面包覆第一流速增强层,可以破坏通电导体外表面形成的边界层,从而增加流经通电导体外表面的液氮流速。因此,第一流速增强层的设置可以保证通电导体外表面流经的液氮的速度,从而提高液氮对通电导体的降温效果,保证通电导体的超导性能。(The present application relates to a superconducting cable. The superconducting cable includes a current-carrying conductor, a cryogenic dewar tube, and a first flow rate enhancing layer. The low temperature dewar pipe surrounds and forms and holds the chamber, and the circular telegram conductor sets up in holding the intracavity, and holds and has filled into the liquid nitrogen in the chamber. The first flow enhancement layer covers the outer surface of the energized conductor for increasing the flow rate of liquid nitrogen flowing over the outer surface of the energized conductor. In the superconducting cable, by coating the first flow velocity reinforcing layer on the outer surface of the current conductor, the boundary layer formed on the outer surface of the current conductor can be broken, thereby increasing the flow velocity of liquid nitrogen flowing through the outer surface of the current conductor. Therefore, the arrangement of the first flow velocity enhancement layer can ensure the speed of liquid nitrogen flowing through the outer surface of the electrified conductor, so that the cooling effect of the liquid nitrogen on the electrified conductor is improved, and the superconducting performance of the electrified conductor is ensured.)

1. A superconducting cable, comprising:

a current-carrying conductor (10);

the low-temperature Dewar pipe (20) surrounds and forms a containing cavity (210), the electrified conductor (10) is arranged in the containing cavity (210), and liquid nitrogen is filled in the containing cavity (210); and

a first flow enhancement layer (30) covering the outer surface of the energized conductor (10) for increasing the flow rate of liquid nitrogen flowing over the outer surface of the energized conductor (10).

2. Superconducting cable according to claim 1,

the energizing conductor (10) includes a cable former (110) and a conductor layer (120), the conductor layer (120) being formed on a surface of the cable former (110) away from an axis thereof;

the superconducting cable further includes a second flow rate enhancing layer (40), the second flow rate enhancing layer (40) covering an inner surface of the cable former (110) away from the conductor layer (120) for increasing a flow rate of liquid nitrogen flowing through the inner surface of the cable former (110).

3. Superconducting cable according to claim 2, characterized in that said energizing conductor (10) further comprises:

the insulating layer (130) is formed on the surface, away from the cable skeleton (110), of the conductor layer (120); and

a shield layer (140) interposed between the insulating layer (130) and the first flow rate enhancing layer (30).

4. Superconducting cable according to claim 2, characterized in that the cable former (110) is a metal bellows.

5. The superconducting cable of claim 1, wherein the first flow rate enhancing layer (30) includes a plurality of adherent particles (310), the plurality of adherent particles (310) being disposed on an outer surface of the current-carrying conductor (10) for enhancing a motive force of liquid nitrogen flowing through the outer surface of the current-carrying conductor (10).

6. The superconducting cable according to claim 5, wherein the first flow rate enhancing layer (30) further includes a sticking layer (320), the sticking layer (320) covers an outer surface of the current-carrying conductor (10), and the plurality of adhesion particles (310) are provided on a surface of the sticking layer (320) away from the current-carrying conductor (10).

7. The superconducting cable of claim 6, wherein the adhesion layer (320) comprises a heat conducting thin film layer (321) and an adhesion layer (322), the heat conducting thin film layer (321) covers the adhesion layer (322), and a surface of the adhesion layer (322) remote from the heat conducting thin film layer (321) covers an outer surface of the current-carrying conductor (10).

8. Superconducting cable according to claim 5, characterized in that said adhesion particles (310) are spherical or cylindrical.

9. Superconducting cable according to claim 5, characterized in that the material of the adhesion particles (310) is a polymeric compound.

10. Superconducting cable according to claim 5, characterized in that said adhesion particles (310) are distributed helically along the outer surface of said current conductor (10).

11. Superconducting cable according to claim 1, characterized in that it further comprises a third flow velocity enhancement layer (50) covering the inner wall of said cryogenic dewar (20) for enhancing the power of the liquid nitrogen flowing through the inner surface of said cryogenic dewar (20).

Technical Field

The application relates to the technical field of power transmission, in particular to a superconducting cable.

Background

In a superconducting cable, a cryogenic dewar tube is generally used, and liquid nitrogen is filled in the cryogenic dewar tube to cool an electrified conductor. In order to achieve a good cooling effect, the liquid nitrogen in the low-temperature dewar tube needs to have certain fluidity.

However, the electrified conductor forms a boundary layer against the surface of the liquid nitrogen, and the liquid nitrogen in the boundary layer has almost no flow velocity. Therefore, the boundary layer on the surface of the electrified conductor greatly influences the cooling effect of the liquid nitrogen on the electrified conductor, so that the superconducting cable is exposed to the risk of quenching.

Disclosure of Invention

In view of this, it is necessary to provide a superconducting cable in order to solve the problem that the boundary layer on the surface of the current-carrying conductor affects the cooling effect of liquid nitrogen on the current-carrying conductor.

The present application provides a superconducting cable, including:

an energizing conductor;

the low-temperature Dewar pipe surrounds to form an accommodating cavity, the electrified conductor is arranged in the accommodating cavity, and liquid nitrogen is filled in the accommodating cavity; and

a first flow enhancement layer covering an outer surface of the energized conductor for increasing a flow rate of liquid nitrogen flowing over the outer surface of the energized conductor.

In one of the embodiments, the first and second electrodes are,

the electrified conductor comprises a cable framework and a conductor layer, and the conductor layer is formed on the surface of the cable framework, which is far away from the axis of the cable framework;

the superconducting cable further includes a second flow rate enhancing layer covering an inner surface of the cable former remote from the conductor layer for increasing a flow rate of liquid nitrogen flowing through the inner surface of the cable former.

In one embodiment, the current-carrying conductor further comprises:

the insulating layer is formed on the surface, far away from the cable framework, of the conductor layer; and

and the shielding layer is clamped between the insulating layer and the first flow velocity enhancement layer.

In one embodiment, the cable framework is a metal corrugated pipe.

In one embodiment, the first flow enhancement layer comprises a plurality of adherent particles disposed on the outer surface of the energized conductor for enhancing the momentum of liquid nitrogen flowing past the outer surface of the energized conductor.

In one embodiment, the first flow rate enhancement layer further comprises an attachment layer covering an outer surface of the current-carrying conductor, and the plurality of attached particles are disposed on a surface of the attachment layer away from the current-carrying conductor.

In one embodiment, the attaching layer comprises a heat-conducting thin film layer and an adhesion layer, the heat-conducting thin film layer covers the adhesion layer, and the surface of the adhesion layer far away from the heat-conducting thin film layer covers the outer surface of the power-on conductor.

In one embodiment, the adherent particles are spherical or cylindrical.

In one embodiment, the material of the attached particles is a polymer compound.

In one embodiment, the adherent particles are distributed helically along an outer surface of the current conductor.

In one embodiment, the superconducting cable further comprises a third flow velocity enhancing layer covering an inner wall of the cryogenic dewar tube for enhancing a motive force of liquid nitrogen flowing through an inner surface of the cryogenic dewar tube.

In the superconducting cable, by coating the first flow velocity reinforcing layer on the outer surface of the current conductor, the boundary layer formed on the outer surface of the current conductor can be broken, thereby increasing the flow velocity of liquid nitrogen flowing through the outer surface of the current conductor. Therefore, the arrangement of the first flow velocity enhancement layer can ensure the flow velocity of liquid nitrogen flowing through the outer surface of the electrified conductor, so that the cooling effect of the liquid nitrogen on the electrified conductor is improved, and the superconducting performance of the electrified conductor is ensured.

Drawings

Fig. 1 is a schematic cross-sectional view of a superconducting cable according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional view of another superconducting cable according to an embodiment of the present invention;

FIG. 3 is a schematic view of a surface structure of a first flow enhancement layer according to an embodiment of the present disclosure;

fig. 4 is a schematic cross-sectional view of a first flow rate enhancing layer according to an embodiment of the present disclosure.

Description of the reference numerals

100 superconducting cable

10 current conductor

110 cable framework

120 conductor layer

130 insulating layer

140 shield layer

20 low-temperature Dewar pipe

210 accommodating chamber

30 first flow rate enhancement layer

310 attached particles

320 adhesive layer

321 heat-conducting film layer

322 adhesion layer

40 second flow rate enhancement layer

50 third flow Rate enhancement layer

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and those skilled in the art will be able to make similar modifications without departing from the spirit of the application and it is therefore not intended to be limited to the embodiments disclosed below.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, the present application provides a superconducting cable 100. Superconducting cable 100 includes a current-carrying conductor 10, a cryogenic dewar tube 20, and a first flow rate enhancing layer 30. The low-temperature Dewar pipe 20 surrounds and forms a containing cavity 210, the electrified conductor 10 is arranged in the containing cavity 210, and liquid nitrogen is filled in the containing cavity 210. The first flow rate enhancement layer 30 covers the outer surface of the electrified conductor 10 for increasing the flow rate of liquid nitrogen flowing through the outer surface of the electrified conductor 10.

It is understood that the low temperature dewar pipe 20 may have a double-layered structure, i.e., divided into an inner pipe and an outer pipe, and a plurality of layers of heat insulating materials may be disposed between the inner pipe and the outer pipe, and the heat insulating materials may insulate the influence of the external environment on the superconducting performance of the current-carrying conductor 10 disposed inside the low temperature dewar pipe 20. Current-carrying conductor 10 is a conductive part in superconducting cable 100, and current-carrying conductor 10 may be a three-phase coaxial cable in the present embodiment. The three-phase coaxial cable is formed by sequentially winding an insulating layer, a three-phase superconducting layer, an insulating layer, a shielding layer and a protective layer on a flexible cable framework from inside to outside, and the insulating layer is also wound between every two superconducting layers in the three-phase superconducting layer. When cooling down three-phase coaxial cable, can pour into the liquid nitrogen in to low temperature dewar pipe 20, the liquid nitrogen can flow in along flexible cable skeleton inner wall to flow out along the passageway between circular telegram conductor 10 surface and the 20 inner tubes of low temperature dewar pipe, thereby accomplish the circulation of liquid nitrogen to circular telegram conductor 10 cooling process.

It is understood that the reynolds number is a dimensionless number that can be used to characterize fluid flow conditions. The use of the reynolds number to distinguish whether the flow of the fluid is laminar or turbulent can also be used to determine the resistance to flow of the object in the fluid. A smaller reynolds number indicates a more significant viscous force effect, and a larger reynolds number indicates a more significant inertial effect. When the reynolds number is small, the influence of the viscous force on the flow field is larger than the inertia, the disturbance of the flow velocity in the flow field is attenuated due to the viscous force, and the fluid flows stably and is laminar. When the reynolds number is larger, the influence of inertia on the flow field is larger than the viscous force, the fluid flow is unstable, small changes of the flow velocity are easy to develop and strengthen, and a turbulent and irregular turbulent flow field is formed.

When liquid nitrogen flows over the outer surface of the current conductor 10, a boundary layer is created on the outer surface of the current conductor 10. The boundary layer is a thin flow layer with non-negligible viscous force close to the object surface in the high-Reynolds number streaming, and is also called as a flow boundary layer or a boundary layer. If the fluid with small viscosity contacts with the object and has relative motion at large Reynolds number, the thin fluid layer close to the object surface is subjected to viscous shear stress to reduce the velocity, i.e. the fluid close to the object surface adheres to the object surface, and the relative velocity with the object surface is equal to zero. Meanwhile, the fluid speed is rapidly increased to the free flow speed, namely the ideal streaming speed, from the object surface to the outside. Therefore, the direction gradient of the velocity in the boundary layer normal to the vertical surface is large, even if the viscosity of the fluid is not large, the viscous force is still large relative to the inertial force, and the viscous flow plays a significant role. While outside the boundary layer, the velocity gradient is small, the viscous forces are negligible, and the flow can be considered as a non-viscous or ideal flow.

Therefore, the boundary layer existing on the outer surface of the electrified conductor 10 can seriously affect the speed of liquid nitrogen flowing through the outer surface of the electrified conductor 10, thereby affecting the cooling effect of the liquid nitrogen on the electrified conductor 10 and the superconducting performance of the electrified conductor 10. By providing the first flow rate enhancement layer 30 on the outer surface of the electrified conductor 10, the boundary layer formed on the outer surface of the electrified conductor 10 can be broken, thereby increasing the flow rate of the liquid nitrogen flowing through the outer surface of the electrified conductor 10. It is understood that the first flow velocity enhancement layer 30 has a rough surface that prevents a boundary layer from being formed on the surface of the energized conductor 10 in contact with liquid nitrogen, thereby increasing turbulence of the surface of the energized conductor 10 in contact with liquid nitrogen. The turbulence increase can improve the cooling effect of the liquid nitrogen on the outer surface of the electrified conductor 10, and ensure the superconducting property of the electrified conductor 10.

In superconducting cable 100, by coating first flow rate enhancement layer 30 on the outer surface of current-carrying conductor 10, the boundary layer formed on the outer surface of current-carrying conductor 10 can be broken, thereby increasing the flow rate of liquid nitrogen flowing through the outer surface of current-carrying conductor 10. In one embodiment, the first flow enhancement layer 30 may be wound around the outer surface of the current conductor 10. Therefore, the first flow velocity enhancement layer 30 can ensure the velocity of the liquid nitrogen flowing through the outer surface of the electrified conductor 10, thereby improving the cooling effect of the liquid nitrogen on the electrified conductor 10 and ensuring the superconducting performance of the electrified conductor 10.

Referring also to fig. 2, in one embodiment, the current conductor 10 includes a cable frame 110 and a conductor layer 120, and the conductor layer 120 is formed on a surface of the cable frame 110 away from an axis thereof. The superconducting cable 100 further includes a second flow rate enhancing layer 40, the second flow rate enhancing layer 40 covering an inner surface of the cable former 110 away from the conductor layer 120 for increasing a flow rate of liquid nitrogen flowing through the inner surface of the cable former 110. In one embodiment, the conductor layer 120 can be wound around the surface of the cable frame 110 away from the axis thereof. It can be understood that, when the three-phase coaxial cable is cooled, the liquid nitrogen can flow in along the inner wall of the cable framework 110 and flow out along the channel between the outer surface of the electrified conductor 10 and the inner pipe of the low-temperature dewar tube 20, so as to complete the circulation of the cooling process of the electrified conductor 10 by the liquid nitrogen. In one embodiment, the cable backbone 110 is a metal corrugated tube. The liquid nitrogen also forms a boundary layer when flowing over the inner surface of the metal bellows. By forming the second flow-rate enhancing layer 40 on the inner surface of the cable framework 110, the boundary layer formed on the surface of the cable framework 110 in contact with the liquid nitrogen can be damaged, so that the turbulence of the surface of the cable framework 110 in contact with the liquid nitrogen is increased, the cooling effect of the liquid nitrogen on the outer surface of the electrified conductor 10 can be improved due to the increased turbulence, and the superconducting characteristic of the electrified conductor 10 is ensured.

In one embodiment, the current conductor 10 further includes an insulating layer 130 and a shielding layer 140. The insulating layer 130 is formed on the surface of the conductor layer 120 away from the cable frame 110. The shielding layer 140 is interposed between the insulating layer 130 and the first flow rate enhancing layer 30. It is understood that the insulating layer 130 can be wound around the surface of the conductive layer 120 away from the cable frame 110, and the shielding layer 140 can be wound around the surface of the insulating layer 130 away from the conductive layer 120. When the shield layer 140 is provided, the magnetic field of the alternating current flowing through the conductor layer 120 can be prevented from leaking to the outside of the superconducting cable 100. The shield layer 140 may be formed using a conductive material. In one embodiment, the copper shield layer can be formed by winding a copper tape around the outer surface of the insulating layer 130. It is understood that a protective layer may be formed on the outer side of the shielding layer 140, and the protective layer may cover the shielding layer 140 and may provide mechanical protection for the shielding layer 140.

In one embodiment, the first flow rate enhancement layer 30 includes a plurality of adherent particles 310, and the plurality of adherent particles 310 are disposed on the outer surface of the electrified conductor 10 for enhancing the momentum of the liquid nitrogen flowing through the outer surface of the electrified conductor 10. It can be understood that by forming the first flow velocity enhancement layer 30 on the outer surface of the electrified conductor 10 by using the plurality of attached particles 310, the boundary layer formed on the outer surface of the electrified conductor 10 can be detached, and the flow velocity of the liquid nitrogen flowing through the outer surface of the electrified conductor 10 is increased, so that the cooling effect of the liquid nitrogen on the electrified conductor 10 is enhanced. It is to be understood that the present application is not limited to the specific shape of the plurality of adhered particles 310, as long as the adhered particles can break away the boundary layer formed on the outer surface of the current-carrying conductor 10. In one embodiment, the plurality of attached particles 310 can be irregular particles that can vary the flow rate in a random manner and can enhance the momentum of the liquid nitrogen flowing through the outer surface of the electrical conductor 10.

In one embodiment, the first flow rate enhancing layer 30 further includes an adhesive layer 320, the adhesive layer 320 covers the outer surface of the current conductor 10, and the plurality of adhesive particles 310 are disposed on the surface of the adhesive layer 320 away from the current conductor 10. It is understood that the plurality of attachment particles 310 may be disposed on the attachment layer 320 in addition to being disposed directly on the outer surface of the current conductor 10. The adhesion layer 320 covers the outer surface of the current conductor 10, and compared with the case where the plurality of adhesion particles 310 are directly disposed on the outer surface of the current conductor 10, the adhesion layer 320 can ensure the connection stability between the plurality of adhesion particles 310 and the outer surface of the current conductor 10.

In one embodiment, the adhesive layer 320 includes a heat conductive film layer 321 and an adhesive layer 322, the heat conductive film layer 321 covers the adhesive layer 322, and a surface of the adhesive layer 322 away from the heat conductive film layer 321 covers an outer surface of the power conductor 10. It is understood that the adhesion layer 322 is an adhesive layer, and the heat conductive film layer 321 can be fixed on the outer surface of the current conductor 10. In one embodiment, the adhesive layer 322 can be applied to the outer side of the current conductor 10, and the heat conductive film layer 321 can be wound around the surface of the adhesive layer 322 away from the current conductor 10. The plurality of attached particles 310 may be attached to the surface of the thermal film 321 away from the adhesive layer 322 regularly or randomly.

In one embodiment, the adherent particles 310 are spherical or cylindrical. When the adhered particles 310 are cylindrical, the bottom surface of the cylindrical particles is flush with the outer surface of the current conductor 10. At the moment, when the liquid nitrogen flows through the first half cylindrical surface of the cylinder, the fluid flows along the cylindrical surface in an acceleration and decompression mode, and the boundary layer gradually increases and develops. When the liquid nitrogen flows through the back half cylindrical surface, the liquid nitrogen performs deceleration pressurization movement, a large amount of kinetic energy is lost due to overcoming of viscous friction in the boundary layer, and sufficient pressure energy cannot be supplemented to balance with the main flow pressure, so that the boundary layer begins to separate, forms a vortex-shaped wake and develops downstream. Since the vortex-like wake can last for a distance of several times the diameter of the cylinder. Therefore, by arranging the cylindrical particles which are continuously and irregularly distributed, the formation of the boundary layer on the outer surface of the electrified conductor 10 can be continuously prevented, so that the turbulence on the surface of the electrified conductor 10 is increased, and the cooling effect on the electrified conductor 10 is improved.

It is to be understood that the material of the attached particles 310 is not limited by the present application. In one embodiment, the material of the adhesive particles 310 is a polymer compound.

Referring also to fig. 3, in one embodiment, the adherent particles 310 are distributed helically along the outer surface of the current conductor 10. It can be understood that by disposing the adhesion particles 310 spirally distributed on the outer surface of the electrified conductor 10, the uniformity of the flow velocity of the liquid nitrogen on the outer surface of the electrified conductor 10 can be ensured, and the cooling effect on the outer surface of the electrified conductor 10 can be ensured. In one embodiment, the adhesive particles 310 may also be distributed spirally on the surface of the adhesive layer 320.

Referring also to fig. 4, in one embodiment, the superconducting cable 100 further includes a third flow velocity enhancing layer 50 covering an inner wall of the cryogenic dewar 20 for enhancing a motive force of the liquid nitrogen flowing through the inner surface of the cryogenic dewar 20. It can be understood that the third flow velocity enhancement layer 50 is formed on the inner wall of the low-temperature dewar tube 20, so that the boundary layer formed on the surface of the low-temperature dewar tube 20 contacting with the liquid nitrogen can be damaged, the turbulence on the surface of the low-temperature dewar tube 20 contacting with the liquid nitrogen is increased, the overall flow velocity of the liquid nitrogen can be increased, the cooling effect on the outer surface of the electrified conductor 10 is ensured, and the superconducting characteristic of the electrified conductor 10 is ensured.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.