CN113393971B - High-vacuum multilayer flexible heat insulation pipe for high-temperature superconducting cable and manufacturing method - Google Patents
High-vacuum multilayer flexible heat insulation pipe for high-temperature superconducting cable and manufacturing method Download PDFInfo
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- CN113393971B CN113393971B CN202110704662.7A CN202110704662A CN113393971B CN 113393971 B CN113393971 B CN 113393971B CN 202110704662 A CN202110704662 A CN 202110704662A CN 113393971 B CN113393971 B CN 113393971B
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Abstract
The utility model provides a high vacuum multilayer flexible thermal insulation pipe and manufacturing method for high temperature superconducting cable, includes outer tube, inner tube, interface flange, its characterized in that: the flexible thermal insulation pipe further comprises: a vacuum interlayer (1) located between the inner tube and the outer tube; a plurality of layers of heat insulation materials (2) which are positioned at one side of the vacuum interlayer close to the outer wall of the inner pipe and are used for heat insulation; the outer wall of the inner pipe is provided with a protrusion (3) so as to reduce the contact area between the multi-layer heat insulating material and the outer wall of the inner pipe. The heat insulation pipe heat insulation material has the advantages of small contact area with the outer wall of the inner pipe, high evacuation efficiency and good heat insulation performance, and the method can accurately calculate and simulate the heat leakage data of different heat insulation pipes, thereby providing powerful guarantee for the design of the heat insulation pipes and the verification of the performance of the heat insulation pipes.
Description
Technical Field
The invention relates to the field of superconducting cables, in particular to a high-vacuum multilayer flexible heat insulation pipe for a high-temperature superconducting cable and a manufacturing method thereof.
Background
The application of superconducting technology in power systems is various, and is one of the main directions of superconducting application research in recent years. Compared with the power cable, the superconducting cable has great advantages such as: the power transmission capability is strong, the cost is saved, the occupied space is small, the line impedance is extremely low, the power transmission loss is small, and the anti-magnetic interference capability is strong; the power transmission device allows long-distance power transmission by adopting relatively low voltage, and can also transmit underground power so as to avoid noise, electromagnetic pollution and potential safety hazard caused by ultra-high voltage high-altitude power transmission and protect ecological environment.
As an important component in high-temperature superconducting cables, flexible thermal insulation pipes can ensure that the superconducting tapes inside the flexible thermal insulation pipes are in a fixed ambient temperature for a long time without the transmission performance of the superconducting tapes being affected by heat leakage or heat transfer. However, there is no known design scheme for a thermal insulation pipe which can accurately and reasonably cope with the thermal insulation performance of the thermal insulation pipe and the design requirements of a superconducting cable.
Therefore, there is a need for a high vacuum multi-layer flexible thermal insulation tube for high temperature superconducting cables and a method of manufacturing the same.
Disclosure of Invention
In order to solve the defects in the prior art, the invention aims to provide the high-vacuum multi-layer flexible heat insulation pipe for the high-temperature superconductive cable and the manufacturing method thereof, wherein the outer wall of the inner pipe of the heat insulation pipe is provided with the protrusions, so that the contact area between the heat insulation material and the outer wall of the inner pipe can be reduced, and the evacuation efficiency of a vacuum interlayer is improved. In addition, the manufacturing method of the invention can accurately estimate the heat leakage of the heat insulation pipe by calculating the heat leakage of the heat insulation pipe, and obtain the optimal design scheme of the heat insulation pipe.
The invention adopts the following technical scheme.
The invention relates to a high-vacuum multilayer flexible heat insulation pipe for a high-temperature superconducting cable, which comprises an outer pipe, an inner pipe and an interface flange, wherein the flexible heat insulation pipe further comprises: a vacuum interlayer 1 positioned between the inner tube and the outer tube; a multi-layer heat insulating material 2 which is positioned on one side of the vacuum interlayer close to the outer wall of the inner tube and is used for heat insulation; the outer wall of the inner pipe is provided with a protrusion 3 to reduce the contact area between the multi-layer heat insulating material and the outer wall of the inner pipe.
Preferably, the height of the protrusions on the outer wall of the inner tube is between 3 and 5mm for reducing the contact area of the multi-layer insulation material with the outer wall of the inner tube to improve the evacuation efficiency of the vacuum interlayer.
Preferably, the protrusions on the outer wall of the inner tube are equally spaced apart on the outer wall of the inner tube.
Preferably, the multilayer heat insulating material includes a multilayer heat insulating unit therein; wherein each layer of heat insulation unit at least comprises a reflecting screen material and a heat insulation material, and the heat insulation material is glass fiber paper or chemical fiber paper.
Preferably, the flexible thermal insulation pipe vacuum interlayer further comprises a support 4 positioned at the middle of the pipe, a hydrogen removing agent 5 positioned at one end of the pipe, and a low-temperature adsorbent 6 positioned at the other end of the pipe; the support 4 is a polytetrafluoroethylene tube or polytetrafluoroethylene ring with holes spirally wound outside the heat insulating material.
The second aspect of the present invention relates to a method for manufacturing a high-vacuum multi-layer flexible thermal insulation pipe for a high-temperature superconducting cable, as in the first aspect of the present invention, comprising the steps of: step 1, acquiring dimension parameters of a flexible thermal insulation pipe for a high-temperature superconducting cable based on a liquid nitrogen flow simulation test in a corrugated pipe and superconducting cable design indexes; step 2, placing the pre-designed multi-layer heat insulation material into a calorimeter to obtain the heat leakage quantity of the multi-layer heat insulation material, and obtaining the heat conduction quantity of the supporting piece in a simulation mode; and 3, designing the internal structure of the thermal insulation pipe based on the thermal insulation requirement of the thermal insulation pipe, and evaluating the design of the internal structure of the thermal insulation pipe based on a heat leakage operation.
Preferably, the dimensional parameters of the flexible thermal insulation piping obtained based on step 1 include at least: the diameter of the inner tube and the diameter of the outer tube of the thermal insulation pipe.
Preferably, step 2 further includes: placing a pre-designed multilayer heat insulation material into a measuring cylinder of a calorimeter and a vacuum cavity outside a heat insulation quilt; injecting a coolant into the protective cylinder to make the temperature of the calorimeter equal to that of the high-temperature superconducting cable; and connecting a measuring cylinder in the calorimeter with the flowmeter, and measuring the heat leakage of the multi-layer heat insulation materials which are designed in advance and have different types so as to select the optimal type.
Preferably, step 2 further includes: the structure of the support is simulated to obtain the structural temperature and leakage heat distribution of the support.
Preferably, the heat leak operation in the step 3 is specifically: step 3.1, obtaining a heat radiation value of the inner tube and the outer tube of the flexible heat insulation tube based on the material, the size, the temperature and the radiation screen layer number between the inner tube and the outer tube of the flexible heat insulation tube; step 3.2, obtaining residual gas leakage heat value of the vacuum layer based on the vacuum degree of the vacuum interlayer and the sizes and the temperatures of the inner tube and the outer tube; step 3.3, setting a heat leakage value of the supporting piece; and 3.4, acquiring the total heat load of the heat insulation pipe based on the heat radiation value of the outer pipe to the inner pipe, the residual gas heat leakage value of the vacuum layer and the heat leakage value of the supporting piece.
Compared with the prior art, the high-vacuum multi-layer flexible heat insulation pipe for the high-temperature superconducting cable and the manufacturing method thereof have the advantages that the contact area of the heat insulation material and the outer wall of the inner pipe can be reduced through the protrusions arranged on the outer wall of the inner pipe, the evacuation efficiency of the vacuum interlayer is improved, and therefore the heat insulation efficiency of the heat insulation pipe is ensured. The manufacturing method of the heat insulation pipe can accurately calculate and simulate the heat leakage data of the heat insulation pipes in different heat insulation pipe design schemes, so as to provide powerful guarantee for the design of the heat insulation pipes and the verification of the performance of the heat insulation pipes.
Drawings
FIG. 1 is a schematic view of a high vacuum multi-layer flexible thermal insulation piping for a high temperature superconducting cable according to the present invention;
FIG. 2 is a schematic flow chart of the steps of the method for manufacturing a high vacuum multi-layer flexible thermal insulation pipe for high temperature superconducting cable according to the present invention;
FIG. 3 is a schematic view showing the structure of a calorimeter used in the method for manufacturing a high-vacuum multi-layer flexible thermal insulation pipe for a high-temperature superconducting cable according to the present invention;
FIG. 4 is a schematic view showing the appearance of a calorimeter used in the method for manufacturing a high-vacuum multi-layer flexible thermal insulation pipe for a high-temperature superconducting cable according to the present invention;
FIG. 5 is a schematic diagram showing the simulation of the temperature and heat conduction distribution of the outer structure of the support member of the polytetrafluoroethylene tube in the method for manufacturing a high-vacuum multilayer flexible thermal insulation tube for a high-temperature superconducting cable according to the present invention;
fig. 6 is a schematic diagram showing the temperature and heat conduction distribution simulation of the internal structure of the support member of the polytetrafluoroethylene tube in the method for manufacturing a high-vacuum multi-layer flexible thermal insulation tube for a high-temperature superconducting cable according to the present invention.
Reference numerals:
1-a vacuum interlayer, wherein the vacuum interlayer is formed by a vacuum layer,
2-a multi-layered thermal insulation material,
3-a protrusion of the first material and the second material,
a 4-support member, which is provided with a plurality of support members,
5-a hydrogen-removing agent, wherein the hydrogen-removing agent,
6-a low-temperature adsorbent, wherein the adsorbent is prepared from a low-temperature catalyst,
a 7-port flange, wherein the flange is provided with a plurality of connecting holes,
8-a vacuum chamber, 9-a measuring cylinder,
10-protecting the copper liquid adding pipe,
11-a protective cylinder, wherein the protective cylinder is provided with a plurality of grooves,
12-the heat-insulating quilt is provided with a heat-insulating layer,
13-flowmeter.
Detailed Description
The present application is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present invention and are not intended to limit the scope of protection of the present application.
Fig. 1 is a schematic structural view of a high vacuum multi-layered flexible thermal insulation pipe for a high temperature superconducting cable according to the present invention. As shown in fig. 1, a high vacuum multi-layer flexible thermal insulation pipe for a high temperature superconducting cable comprises an outer pipe, an inner pipe and an interface flange 7.
The flexible thermal insulation pipe further comprises: a vacuum interlayer 1 positioned between the inner tube and the outer tube; a multi-layer heat insulating material 2 which is positioned on one side of the vacuum interlayer close to the outer wall of the inner tube and is used for heat insulation; the outer wall of the inner pipe is provided with a protrusion 3 to reduce the contact area between the multi-layer heat insulating material and the outer wall of the inner pipe.
During the investigation of high vacuum multilayer insulation, it was found that the individual interlayer pressures of the multilayer insulation 2 were typically 1 to 2 orders of magnitude higher relative to the pressure of the residual interlayer, since there was still unaerated interlayer residual gas between the multilayer insulation 2. Since the heat conduction of the interlayer residual gas may result in an insufficient heat insulation effect, how to reduce the interlayer residual gas and increase the vacuum degree between the multi-layered heat insulating materials cannot be neglected. In addition, since the evacuation resistance of the multi-layer heat insulating material is large, the evacuation efficiency is low and the evacuation time is long, which causes not only energy consumption during the evacuation process but also unsatisfactory evacuation effect. Therefore, the invention provides a high-vacuum multilayer heat insulation scheme with the bulges 3 on the outer wall of the inner pipe of the heat insulation pipe on the basis of high-vacuum multilayer heat insulation.
Since the protrusion 3 is added to the outer wall of the thermal insulation pipe, the reduction of the contact area between the multi-layer material and the outer wall of the inner pipe is effectively reduced, thereby greatly reducing the solid heat conduction. The air gap is formed between the protrusions 3, which enables the vacuum-pumping device to effectively evacuate the air present between the multi-layer material and the outer wall of the inner tube. Meanwhile, as the pressure between the multi-layered heat insulating materials decreases, the gas heat conduction decreases and the evacuation efficiency increases further.
Preferably, the height of the protrusions 3 on the outer wall of the inner tube is between 3 and 5mm for reducing the contact area of the multi-layer insulation material 2 with the outer wall of the inner tube to improve the evacuation efficiency of the vacuum interlayer.
Preferably, the protrusions 3 on the outer wall of the inner tube are equally spaced on the outer wall of the inner tube. In particular, the protrusions 3 are arranged on the outer wall of the inner tube at regular intervals, while the remaining structure on the outer wall of the inner tube is kept unchanged.
Preferably, the multilayer heat insulating material 2 includes therein a multilayer heat insulating unit; wherein each layer of heat insulation unit at least comprises a reflecting screen material and a heat insulation material, and the heat insulation material is glass fiber paper or chemical fiber paper. In an embodiment of the present invention, the plurality of layers of heat insulating materials may be three layers, and each layer of heat insulating material has a different structure, and a plurality of layers of different materials may be manufactured by pressing, etc., but each layer of heat insulating material must include a reflective screen layer for realizing anti-radiation and a heat insulating layer for realizing heat insulation. In one embodiment of the present invention, the insulation material is provided in each of the plurality of layers of insulation material with different materials and layers. Specifically, in each layer of the heat insulating material, an adsorbing material, a radiation reflecting material, a heat insulating material, and a fixing material may be included. For example, the adsorption material is used for adsorbing interlayer gases, such as water vapor, nitrogen, oxygen and the like, so as to improve the vacuum degree between the material layers, thereby reducing heat conduction of the interlayer gases and improving heat insulation performance. The anti-radiation material may act as a reflective screen to reflect light to reduce radiative heat transfer. The heat insulating material, such as glass fiber paper and chemical fiber paper, can be used for separating the reflecting screens, preventing direct contact between the reflecting screens and reducing heat conduction. The fixing material such as glass fiber tape can be used for fixing each layer of heat insulation material, so that the heat insulation pipe is prevented from being damaged due to material falling, and the firmness and safety of the heat insulation structure are ensured.
Preferably, the flexible thermal insulation pipe vacuum interlayer 1 also comprises a supporting piece 4 positioned at the middle position of the pipe, a dehydrogenation agent 5 positioned at one end of the pipe and a low-temperature adsorbent 6 positioned at the other end of the pipe; the support 4 is a polytetrafluoroethylene tube or polytetrafluoroethylene ring with holes spirally wound outside the heat insulating material.
The second aspect of the present invention relates to a method for manufacturing a high vacuum multi-layer flexible thermal insulation pipe for a high temperature superconducting cable. Fig. 2 is a schematic flow chart showing the steps of the method for manufacturing a high vacuum multi-layer flexible thermal insulation pipe for high temperature superconducting cable according to the present invention. As shown in fig. 2, the method of the present invention includes steps 1 to 3.
The flexible thermal insulation pipe of the present invention is based on a heat leak operation on the flexible thermal insulation pipe. In general, there are two methods for calculating the heat leak of the heat insulating material. The first is to calculate the heat leak of each layer of material in the multi-layer heat insulating material layer by layer. The second is to calculate the radiation, convection and conduction of the multilayer insulation independently and then algebraically sum the data. However, since the multi-layer heat insulating material not only involves heat conduction between radiation, convection, gas and solid, but also has secondary effects between the radiation and the heat conduction, and since the heat leakage performance of the multi-layer heat insulating material is easily affected by various factors such as a pretreatment process, a binding implementation process, and vacuum performance of the material, the theoretical calculation result of the multi-layer heat insulating material cannot well satisfy the needs of practical engineering.
In practical engineering experience, the method of engineering calorimeter experimental test can be adopted to obtain the heat insulation performance of the multi-layer material under high vacuum. Meanwhile, the heat of the supporting piece, the inner pipeline, the outer pipeline and other structures can be calculated based on a heat transfer theory, so that the total heat leakage of the heat insulation pipe is finally obtained.
And step 1, acquiring the dimension parameters of the flexible thermal insulation pipe for the high-temperature superconducting cable based on a liquid nitrogen flow simulation test in the corrugated pipe and a superconducting cable design index.
Preferably, the dimensional parameters of the flexible thermal insulation piping obtained based on step 1 include at least: the diameter of the inner tube and the diameter of the outer tube of the thermal insulation pipe. In one embodiment of the present invention, the stainless steel inner tube of the thermal insulation pipe may be provided with a diameter of 120mm, the stainless steel outer tube has a diameter of 180mm,
in addition, the outer diameter of the cable formed inside the stainless steel inner pipe is 100mm when the conductor core is formed according to the design size parameter of the cable formed by the superconducting cable core. And setting welding gaps of the heat insulation pipe according to the welding requirements, the protection requirements, the molding requirements and the manufacturing experience of the corrugated pipe. Wherein, the welding gap of the inner tube can be 20mm, and the welding gap of the outer tube can be 18mm. In addition, the thickness of the metal net sleeve can be 1mm, the thickness of the inner support is 5mm, the thickness of the outer support is 6mm, the thickness of the heat insulation layer is 9mm, and the like.
And 2, placing the pre-designed multi-layer heat insulation material in a calorimeter to obtain the heat leakage quantity of the multi-layer heat insulation material, and simulating to obtain the heat conduction quantity of the support.
Preferably, step 2 further includes: placing a pre-designed multilayer heat insulation material into a measuring cylinder of a calorimeter and a vacuum cavity outside a heat insulation quilt; injecting a coolant into the protective cylinder to make the temperature of the calorimeter equal to that of the high-temperature superconducting cable;
and connecting a measuring cylinder in the calorimeter with a flowmeter, and measuring the heat leakage of the pre-designed multi-layer heat insulation materials with different types to select the optimal type.
Fig. 3 is a schematic view showing the structure of a calorimeter used in the method for manufacturing a high-vacuum multi-layer flexible thermal insulation pipe for a high-temperature superconducting cable according to the present invention. Fig. 4 is a schematic view showing the appearance of a calorimeter in the method for manufacturing a high-vacuum multi-layer flexible thermal insulation pipe for a high-temperature superconducting cable according to the present invention. As shown in fig. 3 and 4, the calorimeter comprises a vacuum chamber 8, a measuring cylinder 9 connected with a flowmeter 13, and a protective cylinder filling pipe 10 for filling refrigerating liquid. The measuring cylinder 9 and the protecting cylinder 11 are in the shape of a cylinder and are coaxially arranged with the cylindrical shell of the calorimeter. Outside the protective and measuring cylinders there is also provided a heat insulation quilt 12.
In step 1, a plurality of different multi-layered heat insulating materials, which are expected to be used in the present invention, may be sequentially laid on the heat insulating quilt outer layer. The liquid is added into the protection cylinder through the liquid adding pipe, for example, liquid nitrogen is added, so that the temperature inside the calorimeter is consistent with the normal working state of the superconducting cable under the liquid nitrogen. And acquiring flow data of the measuring cylinder through the flowmeter, and obtaining the heat leakage quantity of the multi-layer heat insulation material.
Since three different multi-layered heat insulating materials are designed in advance in the present invention. Three different multi-layered insulation materials, namely, the first, second and third insulation units shown in fig. 2, may be referred to herein as an empty composite insulation unit, a multi-layered insulation unit, a bump insulation unit, in that order. The layers and the laying arrangement modes of different materials in the three heat insulating materials are different.
By testing the heat leakage of these three materials, the heat leakage performance of the three multi-layer insulation materials can be compared.
Table 1 thermal insulation performance table of three different multi-layered thermal insulation materials designed in advance
The heat leakage of the multilayer heat insulating material provided in a cylindrical environment having an inner tube diameter of 120mm and an outer tube diameter of 180mm was measured by a calorimeter. The total heat leakage of the hollow composite insulation material was 250W, the heat leakage of the multilayer insulation material was 103W, and the heat leakage of the bump insulation material was 90W. In addition, since the heat transfer areas of the three materials are equal and are 150m 2 Thus, it was possible to obtain three materials having specific heat flows of 1.67W/m, respectively 2 、0.69W/m 2 And 0.60W/m 2 。
As can be seen from comparing the specific heat flow parameters of the three materials, the thermal insulation performance of the bump thermal insulation material is best, the thermal insulation performance of the multilayer thermal insulation material is inferior, and the thermal insulation performance of the hollow composite thermal insulation material is worst. Therefore, a verified insulation material can be selected for use in the insulated pipe according to the above-described experiment.
In addition, the heat conduction quantity of the supporting piece is checked in the step 2. The present invention may employ two different support structures. The first is a polytetrafluoroethylene tube externally spirally wound with a heat insulating material, and the second is a polytetrafluoroethylene ring with holes.
Specifically, step 2 further includes: the structure of the support is simulated to obtain the structural temperature and leakage heat distribution of the support. Fig. 5 is a schematic diagram showing the simulation of the temperature and heat conduction distribution of the outer structure of the support member of the polytetrafluoroethylene tube in the method for manufacturing the high-vacuum multi-layer flexible thermal insulation tube for high-temperature superconducting cable according to the present invention. Fig. 6 is a schematic diagram showing the temperature and heat conduction distribution simulation of the internal structure of the support member of the polytetrafluoroethylene tube in the method for manufacturing a high-vacuum multi-layer flexible thermal insulation tube for a high-temperature superconducting cable according to the present invention. As shown in fig. 5 and 6, the structure of the support is simulated by simulation software commonly used in the prior art, and the temperature and heat leakage at different parts of the support are simulated. The support used in the present invention had a heat leak of 8.1W.
And 3, designing the internal structure of the thermal insulation pipe based on the thermal insulation requirement of the thermal insulation pipe, and evaluating the design of the internal structure of the thermal insulation pipe based on a heat leakage operation.
According to the heat leakage quantity of the multi-layer heat insulation material and the heat conduction quantity data of the supporting piece obtained in the step 2, compared with the heat insulation requirement of the superconducting cable heat insulation pipe, the internal structure of the heat insulation pipe can be initially designed.
Specifically, three different design methods can be employed for the internal structure of the thermal insulation piping in the present invention. The first method is to add multiple layers of insulating materials and glass wool between the inner and outer pipes of the insulating pipe. The temperature of the inner pipe and the outer pipe is isolated by two modes of heat insulating materials and superfine glass wool. The second approach is to use a high vacuum multilayer insulating flexible jacket. A plurality of layers of heat insulating materials, for example, three layers of heat insulating materials, are arranged outside the inner tube, and the space between the inner tube and the outer tube is sealed and evacuated, and heat insulation is performed by the vacuum and the heat insulating materials. Since in the second method, a large amount of air exists in the gap between the heat insulating material and the inner tube, and it is difficult to extract it by the vacuum extractor. Thus, in the present invention, the third method is employed. The third method is to use high vacuum multi-layer heat insulation flexible sleeve, and the outer wall of the inner tube is provided with protrusions according to a certain rule. Due to the presence of the protrusions, air between the outer wall of the inner tube and the multi-layer insulation material is more easily extracted, thereby ensuring the insulation performance of the vacuum interlayer. Therefore, the third method has a better heat insulating effect than the second method, can improve the heat insulating efficiency by 8% to 10%, and can improve the evacuation efficiency by about 30%.
Specifically, calculation of the theory of heat leakage may be performed according to the design scheme to evaluate the design scheme.
Preferably, the heat leak operation in step 3 is specifically as follows:
and 3.1, acquiring a heat radiation value of the inner tube and the outer tube of the flexible thermal insulation tube based on the material, the size, the temperature and the radiation screen layer number between the inner tube and the outer tube of the flexible thermal insulation tube.
The heat radiation amount calculation formula of the outer tube to the inner tube in the flexible heat insulation tube is as follows:
wherein epsilon is emissivity;
sigma is a stefin-boltzmann constant and has sigma=5.67×10 -8 W/(m 2 ·K 4 )；
A is the surface area of the inner tube of the flexible thermal insulation tube;
T 2 for the outer tube temperature, there is T in the embodiment of the invention 2 ＝300K；
T 1 For the inner tube temperature, T is present in the examples of the invention 1 ＝68K；
F 1-2 An angular coefficient for radiation heat transfer, and having F 1-2 ＝1；
n is the number of layers of the radiant screen and is related to the composition of the multi-layer insulation material.
In addition, for parameter ε 1-2 The calculation formula is as follows:
wherein ε 1 And epsilon 2 Stainless steel has emissivity at normal and low temperatures (i.e., 68K), respectively.
Substituting the formula (2) into the formula (1) to obtain the heat radiation value Q of the outer tube to the inner tube of the heat insulation pipe 1 ＝0.132W/m。
And 3.2, obtaining residual gas leakage heat value of the vacuum layer based on the vacuum degree of the vacuum interlayer and the sizes and the temperatures of the inner tube and the outer tube.
In the method, the calculation formula of residual gas heat leakage is as follows:
Q 2 ＝k×a×p×(T 2 -T 1 )×A
(3)
where k is a coefficient and there is k= 1.2001;
a is a thermal adaptation coefficient and has a=1;
p is the degree of interlayer vacuum, in the present invention, p=0.01 Pa.
According to the method of the invention, Q 2 ＝1.01W/m。
And 3.3, setting a heat leakage value of the supporting piece.
In the present invention, the heat leak value of the support may be set, or approximated by a simulation method. In the invention, the leakage heat value of the support member can be set to be Q 3 ＝0.713W/m。
And 3.4, acquiring the total heat load of the heat insulation pipe based on the heat radiation value of the outer pipe to the inner pipe, the residual gas heat leakage value of the vacuum layer and the heat leakage value of the supporting piece.
In the invention, the calculation formula of the total heat load of the heat insulation pipe is as follows:
Q＝Q 1 +Q 2 +Q 3 (4)
according to the method of the present invention, the total heat load Q of the thermal insulation pipe is approximately 1.9W/m.
Compared with the prior art, the high-vacuum multi-layer flexible heat insulation pipe for the high-temperature superconducting cable and the manufacturing method thereof have the advantages that the contact area of the heat insulation material and the outer wall of the inner pipe can be reduced through the protrusions arranged on the outer wall of the inner pipe, the evacuation efficiency of the vacuum interlayer is improved, and therefore the heat insulation efficiency of the heat insulation pipe is ensured. The manufacturing method of the heat insulation pipe can accurately calculate and simulate the heat leakage data of the heat insulation pipes in different heat insulation pipe design schemes, so as to provide powerful guarantee for the design of the heat insulation pipes and the verification of the performance of the heat insulation pipes.
While the applicant has described and illustrated the embodiments of the present invention in detail with reference to the drawings, it should be understood by those skilled in the art that the above embodiments are only preferred embodiments of the present invention, and the detailed description is only for the purpose of helping the reader to better understand the spirit of the present invention, and not to limit the scope of the present invention, but any improvements or modifications based on the spirit of the present invention should fall within the scope of the present invention.
Claims (10)
1. A flexible heat-insulating pipe of high vacuum multilayer for high temperature superconducting cable, including outer tube, inner tube, interface flange, its characterized in that:
the flexible thermal insulation pipe further comprises:
a vacuum interlayer (1) located between the inner tube and the outer tube;
a plurality of layers of heat insulation materials (2) which are positioned on one side of the vacuum interlayer close to the outer wall of the inner tube and are used for heat insulation, wherein each layer of the plurality of layers of heat insulation materials comprises an adsorption material, a radiation-reflecting material, a heat insulation material and a fixing material, and the fixing material is used for preventing falling and ensuring the firmness of a heat insulation structure;
the outer wall of the inner pipe is provided with a protrusion (3) so as to reduce the contact area between the multi-layer heat insulating material and the outer wall of the inner pipe.
2. The high vacuum multi-layer flexible thermal insulation pipe for high temperature superconducting cable according to claim 1, wherein:
the height of the protrusions on the outer wall of the inner tube is between 3 and 5mm, and the protrusions are used for reducing the contact area between the multi-layer heat insulation material and the outer wall of the inner tube so as to improve the evacuation efficiency of the vacuum interlayer.
3. The high vacuum multi-layered flexible thermal insulation pipe for high temperature superconducting cable according to claim 2, wherein:
the protrusions on the outer wall of the inner tube are distributed on the outer wall of the inner tube at equal intervals.
4. The high vacuum multi-layer flexible thermal insulation pipe for high temperature superconducting cable according to claim 1, wherein:
the multi-layer heat insulation material comprises a multi-layer heat insulation unit;
wherein each layer of heat insulation unit at least comprises a reflecting screen material and a heat insulation material, and the heat insulation material is glass fiber paper or chemical fiber paper.
5. The high vacuum multi-layer flexible thermal insulation pipe for high temperature superconducting cable according to claim 1, wherein:
the vacuum interlayer of the flexible thermal insulation pipe also comprises a supporting piece (4) positioned in the middle of the pipe, a dehydrogenation agent (5) positioned at one end of the pipe and a low-temperature adsorbent (6) positioned at the other end of the pipe;
the supporting piece (4) is a polytetrafluoroethylene tube or a polytetrafluoroethylene ring with holes which is spirally wound outside the heat insulating material.
6. A method of manufacturing a high vacuum multi-layered flexible thermal insulation pipe for high temperature superconducting cables according to any one of claims 1 to 5, comprising the steps of:
step 1, acquiring dimension parameters of a flexible thermal insulation pipe for a high-temperature superconducting cable based on a liquid nitrogen flow simulation test in a corrugated pipe and superconducting cable design indexes;
step 2, placing a pre-designed multi-layer heat insulation material into a calorimeter to obtain the heat leakage quantity of the multi-layer heat insulation material, and obtaining the heat conduction quantity of a supporting piece in a simulation mode;
and 3, designing the internal structure of the thermal insulation pipe based on the thermal insulation requirement of the thermal insulation pipe, and evaluating the design of the internal structure of the thermal insulation pipe based on a heat leakage operation.
7. The method for manufacturing a high vacuum multi-layered flexible thermal insulation pipe for high temperature superconducting cable according to claim 6, wherein:
the dimensional parameters of the flexible thermal insulation pipe obtained based on the step 1 at least comprise: the diameter of the inner tube and the diameter of the outer tube of the thermal insulation pipe.
8. The method for manufacturing a high vacuum multi-layered flexible thermal insulation pipe for high temperature superconducting cable according to claim 6, wherein:
the step 2 further includes:
placing the pre-designed multi-layer heat insulation material into a measuring cylinder of a calorimeter and a vacuum cavity outside a heat insulation quilt;
injecting a coolant into the protective tube so that the temperature of the calorimeter is equal to that of the high-temperature superconducting cable;
and connecting a measuring cylinder in the calorimeter with a flowmeter, and measuring the heat leakage of the pre-designed multi-layer heat insulation materials with different types to select the optimal type.
9. The method for manufacturing a high vacuum multi-layered flexible thermal insulation pipe for high temperature superconducting cable according to claim 6, wherein:
the step 2 further includes:
the structure of the support is simulated to obtain the structural temperature and leakage heat distribution of the support.
10. The method for manufacturing a high vacuum multi-layered flexible thermal insulation pipe for high temperature superconducting cable according to claim 6, wherein:
the heat leak operation in the step 3 specifically includes:
step 3.1, obtaining a heat radiation value of the outer tube in the flexible heat insulation tube to the inner tube based on the materials, the sizes, the temperatures and the radiation screen layers between the inner tube and the outer tube in the flexible heat insulation tube;
step 3.2, obtaining residual gas leakage heat value of the vacuum layer based on the vacuum degree of the vacuum interlayer and the sizes and the temperatures of the inner tube and the outer tube;
step 3.3, setting a leakage heat value of the supporting piece;
and 3.4, obtaining the total heat load of the heat insulation pipe based on the heat radiation value of the outer pipe to the inner pipe, the residual gas heat leakage value of the vacuum layer and the heat leakage value of the supporting piece.
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| CN202110704662.7A CN113393971B (en) | 2021-06-24 | 2021-06-24 | High-vacuum multilayer flexible heat insulation pipe for high-temperature superconducting cable and manufacturing method |
| PCT/CN2021/142411 WO2022267417A1 (en) | 2021-06-24 | 2021-12-29 | High-vacuum multi-layer flexible thermal insulation tube for high-temperature superconducting cable and fabrication method |
| AU2021338587A AU2021338587B2 (en) | 2021-06-24 | 2021-12-29 | High-vacuum multi-layer flexible heat-insulated pipe for high-temperature superconducting cable and manufacturing method thereof |
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| JP4689984B2 (en) * | 2004-07-20 | 2011-06-01 | 株式会社ワイ・ワイ・エル | DC superconducting power transmission cable and power transmission system |
| JP4565385B2 (en) * | 2004-12-01 | 2010-10-20 | 住友電気工業株式会社 | Vacuum insulation tube |
| JP5505865B2 (en) * | 2010-04-22 | 2014-05-28 | 住友電気工業株式会社 | Insulated tube and superconducting cable |
| JP2012074340A (en) * | 2010-09-01 | 2012-04-12 | Fujikura Ltd | High-temperature superconducting cable |
| CN102705695A (en) * | 2012-05-29 | 2012-10-03 | 张家港市科华化工装备制造有限公司 | Laminated structure and bundling method for multi-layer heat-insulating material in interlayer of low-temperature heat-insulating gas cylinder |
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| CN109411148A (en) * | 2018-11-29 | 2019-03-01 | 深圳供电局有限公司 | A kind of vacuum insulation hyperconductive cable structure |
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