CN113393971A - High-vacuum multi-layer flexible heat-insulating pipe for high-temperature superconducting cable and manufacturing method thereof - Google Patents
High-vacuum multi-layer flexible heat-insulating pipe for high-temperature superconducting cable and manufacturing method thereof Download PDFInfo
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- CN113393971A CN113393971A CN202110704662.7A CN202110704662A CN113393971A CN 113393971 A CN113393971 A CN 113393971A CN 202110704662 A CN202110704662 A CN 202110704662A CN 113393971 A CN113393971 A CN 113393971A
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Abstract
The high vacuum multi-layer flexible heat insulation pipe for the high temperature superconducting cable comprises an outer pipe, an inner pipe and an interface flange, and is characterized in that: the flexible thermal insulation piping further comprises: a vacuum interlayer (1) located between the inner tube and the outer tube; the multilayer heat insulation material (2) is positioned on one side, close to the outer wall of the inner pipe, in the vacuum interlayer and used for heat insulation; the outer wall of the inner pipe is provided with a bulge (3) to reduce the contact area of the multilayer heat-insulating material and the outer wall of the inner pipe. The method has the advantages of small contact area between the heat insulating material of the heat insulating pipe and the outer wall of the inner pipe, high evacuation efficiency and good heat insulating performance, can accurately calculate and simulate the heat leakage data of different heat insulating pipes, and provides powerful guarantee for the design of the heat insulating pipe and the verification of the performance of the heat insulating pipe.
Description
Technical Field
The present invention relates to the field of superconducting cables, and more particularly, to a high vacuum multi-layer flexible heat insulating pipe for a high temperature superconducting cable and a method of manufacturing the same.
Background
The application of superconducting technology in power systems is various, and is one of the main directions of research on superconducting application in recent years. Compared to power cables, superconducting cables have great advantages, such as: the power transmission capacity 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 capacity is strong; the method allows long-distance power transmission with relatively low voltage, and can also transmit power underground, thereby avoiding noise, electromagnetic pollution and potential safety hazard caused by ultrahigh-voltage high-altitude power transmission and protecting the ecological environment.
As an important component in the high-temperature superconducting cable, the flexible thermal insulation pipe can ensure that the superconducting tape inside the flexible thermal insulation pipe is kept within a fixed ambient temperature for a long time without affecting the transport performance of the superconducting tape due to heat leakage or heat transfer. However, there has not been provided in the prior art a thermal insulation piping design scheme capable of precisely and reasonably addressing the thermal insulation performance of the thermal insulation piping and the design requirements of the superconducting cable.
Therefore, a high vacuum multi-layer flexible heat-insulating pipe for a high temperature superconducting cable and a method for manufacturing the same are needed.
Disclosure of Invention
In order to solve the problems of the prior art, an object of the present invention is to provide a high vacuum multi-layered flexible heat insulating pipe for a high temperature superconducting cable, which has a protrusion on an outer wall of an inner pipe thereof to reduce a contact area between a heat insulating material and the outer wall of the inner pipe, thereby improving an evacuation efficiency of a vacuum interlayer, and a method for manufacturing the same. In addition, the manufacturing method of the invention can accurately estimate the heat leakage of the heat-insulating pipe by calculating the heat leakage of the heat-insulating pipe and obtain the optimal design scheme of the heat-insulating pipe.
The invention adopts the following technical scheme.
The invention relates to a high vacuum multi-layer 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: the vacuum interlayer 1 is positioned between the inner pipe and the outer pipe; the multilayer heat insulating material 2 is positioned on one side, close to the outer wall of the inner pipe, in the vacuum interlayer and used for heat insulation; the outer wall of the inner pipe is provided with a bulge 3 to reduce the contact area of the multilayer 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-layered 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 on the outer wall of the inner tube.
Preferably, the multilayer heat insulating material comprises a plurality of layers of heat insulating units; wherein, each layer of heat insulation unit at least comprises a reflection screen material and a heat insulation material, and the heat insulation material is glass fiber paper or chemical fiber paper.
Preferably, the flexible heat-insulating pipe vacuum interlayer also comprises a support 4 positioned in 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 supporting piece 4 is a polytetrafluoroethylene tube or a polytetrafluoroethylene ring with holes spirally wound outside the heat insulating material.
A second aspect of the present invention relates to a method for manufacturing a high-vacuum multi-layer flexible thermal insulation piping for a high-temperature superconducting cable as in the first aspect of the present invention, comprising the steps of: step 1, obtaining size parameters of a flexible heat insulation pipe for the high-temperature superconducting cable based on a liquid nitrogen flow simulation test in the corrugated pipe and design indexes of the superconducting cable; step 2, placing the pre-designed multilayer heat-insulating material into a calorimeter to obtain the heat leakage quantity of the multilayer heat-insulating material, and simulating to obtain the heat conduction quantity of the supporting piece; and 3, designing the internal structure of the heat-insulating pipe based on the heat-insulating requirement of the heat-insulating pipe, and evaluating the design of the internal structure of the heat-insulating pipe based on 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 pipe and the diameter of the outer pipe of the heat insulation pipe.
Preferably, step 2 further comprises: placing a multi-layer heat-insulating material designed in advance into a measuring cylinder of a calorimeter and a vacuum cavity outside a heat-insulating 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 quantity of the multi-layer heat-insulating materials with different models designed in advance so as to select the optimal model.
Preferably, step 2 further comprises: the structure of the support is simulated to obtain the structural temperature and heat leakage distribution of the support.
Preferably, the heat leakage operation in step 3 is specifically: step 3.1, obtaining the value of the heat radiation quantity of the inner pipe and the outer pipe in the flexible heat-insulating pipe to the inner pipe based on the materials, the sizes and the temperatures of the inner pipe and the outer pipe in the flexible heat-insulating pipe and the number of layers of radiation screens between the inner pipe and the outer pipe; 3.2, acquiring residual gas heat leakage values of the vacuum layer based on the vacuum degree of the vacuum interlayer and the sizes and the temperatures of the inner pipe and the outer pipe; step 3.3, setting a value of the heat leakage quantity of the supporting piece; and 3.4, acquiring the total heat load of the heat insulation pipe based on the value of the heat radiation quantity of the outer pipe to the inner pipe, the value of the residual gas heat leakage quantity of the vacuum layer and the value of the heat leakage quantity of the supporting member.
The present invention has the advantages that, compared with the prior art, the high vacuum multi-layer flexible heat insulation pipe for high temperature superconducting cable and the manufacturing method thereof according to the present invention can reduce the contact area between the heat insulation material and the outer wall of the inner pipe through the protrusion arranged on the outer wall of the inner pipe, improve the evacuation efficiency of the vacuum interlayer, and thus ensure the heat insulation efficiency of the heat insulation pipe. The method for manufacturing the heat-insulating pipe can accurately calculate and simulate the heat leakage data of the heat-insulating pipe in different heat-insulating pipe design schemes, so as to provide powerful guarantee for the design of the heat-insulating pipe and the verification of the performance of the heat-insulating pipe.
Drawings
FIG. 1 is a schematic view showing the construction 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 showing the steps of a method for manufacturing a high-vacuum multi-layer flexible thermal insulation piping for a high-temperature superconducting cable according to the present invention;
FIG. 3 is a schematic view showing the construction of a calorimeter used in the method for producing a high-vacuum multi-layer flexible heat-insulating tube 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 producing a high-vacuum multi-layer flexible heat-insulating pipe for a high-temperature superconducting cable according to the present invention;
FIG. 5 is a schematic view showing a simulation of the outer structural temperature and the heat conduction distribution of the support member of the polytetrafluoroethylene tube in the method for manufacturing the high-vacuum multi-layer flexible heat-insulating tube for a high-temperature superconducting cable according to the invention;
fig. 6 is a schematic view showing a simulation of the internal structural temperature and the heat conduction distribution of the support member of the polytetrafluoroethylene tube in the method for manufacturing the high-vacuum multi-layer flexible heat-insulating tube for a high-temperature superconducting cable according to the present invention.
Reference numerals:
1-vacuum interlayer, namely,
2-a plurality of layers of heat-insulating materials,
3-the protrusions are arranged on the surface of the substrate,
4-a support member for supporting the support member,
5-a hydrogen removing agent, wherein the hydrogen removing agent is a hydrogen removing agent,
6-a low-temperature adsorbent is added,
7-an interface flange, wherein the interface flange is provided with a flange,
8-a vacuum chamber, 9-a measuring cylinder,
10-protection of the copper liquid feeding pipe,
11-a protective cylinder, wherein the protective cylinder is arranged in the protective cylinder,
12-a thermally insulating cover is placed over the top,
13-flow meter.
Detailed Description
The present application is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present application is not limited thereby.
Fig. 1 is a schematic view showing the construction of a high vacuum multi-layer 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 includes an outer pipe, an inner pipe, and an interface flange 7.
The flexible thermal insulation piping further comprises: the vacuum interlayer 1 is positioned between the inner pipe and the outer pipe; the multilayer heat insulating material 2 is positioned on one side, close to the outer wall of the inner pipe, in the vacuum interlayer and used for heat insulation; the outer wall of the inner pipe is provided with a bulge 3 to reduce the contact area of the multilayer heat insulating material and the outer wall of the inner pipe.
In the research process of high vacuum multi-layer heat insulation, it is found that the pressure intensity between each layer of the multi-layer heat insulation material 2 is generally 1-2 orders of magnitude higher than that of the residual interlayer, because the multi-layer heat insulation material 2 still has the non-evacuated interlayer residual gas between the layers. Since the heat conduction of the interlayer residual gas causes the heat insulation effect to be not good enough, it is not negligible how to reduce the interlayer residual gas and increase the vacuum degree between the multiple layers of heat insulation materials. In addition, because the multilayer heat-insulating material has large evacuation resistance, low evacuation efficiency and long evacuation time, energy consumption is caused in the evacuation process, and the evacuation effect is not ideal. Therefore, the invention provides a high vacuum multi-layer heat insulation scheme with bulges (3) on the outer wall of the inner pipe of the heat insulation pipe on the basis of high vacuum multi-layer heat insulation.
The addition of the projections 3 on the outer wall of the thermal insulation pipe effectively reduces the reduction of the contact area between the multi-layer material and the outer wall of the inner pipe, thereby greatly reducing the solid heat conduction. The air gap between the protrusions 3 enables the evacuation device to efficiently evacuate the air present between the multilayer material and the outer wall of the inner tube. Meanwhile, as the pressure between the multiple layers of the heat insulating material is reduced, the heat conduction of the gas is reduced, and the evacuation efficiency is further improved.
Preferably, the height of the protrusions 3 on the outer wall of the inner pipe is between 3 and 5mm for reducing the contact area of the multi-layered insulation material 2 with the outer wall of the inner pipe 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. Specifically, the protrusions 3 are arranged on the outer wall of the inner tube at regular intervals while keeping the remaining structure on the outer wall of the inner tube unchanged.
Preferably, the multilayer insulation material 2 includes a multilayer insulation unit therein; wherein, each layer of heat insulation unit at least comprises a reflection 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 multi-layer thermal insulation material may have three layers, each layer of thermal insulation material has a different structure, and each layer of thermal insulation material may further include a plurality of layers of different materials manufactured by pressing or the like, but all of the layers of thermal insulation material must include a reflective screen layer for achieving radiation reflection and a thermal insulation layer for achieving thermal insulation. In an embodiment of the present invention, each of the plurality of layers of the thermal insulation material has different thermal insulation material and different number of 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 adsorbent material is used to adsorb interlayer gases such as water vapor, nitrogen, oxygen, and the like to increase the degree of vacuum between material layers, thereby reducing interlayer gas heat conduction and improving thermal insulation performance. The radiation-reflecting material may act as a reflective screen to reduce radiative heat transfer. The heat insulating material such as glass fiber paper and chemical fiber paper can be used for spacing 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 insulating material, so that the heat insulating pipe is prevented from being damaged due to falling off of the material, and the firmness and safety of the heat insulating structure are ensured.
Preferably, the flexible heat-insulating tube vacuum interlayer 1 further comprises a support 4 at the middle position of the tube, a hydrogen scavenger 5 at one end of the tube, and a low-temperature adsorbent 6 at the other end of the tube; the support 4 is a polytetrafluoroethylene tube or a perforated polytetrafluoroethylene ring spirally wound around the heat insulating material.
A second aspect of the present invention relates to a method for manufacturing a high-vacuum multi-layer flexible heat-insulating 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 piping for a 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 heat-insulating pipe according to the present invention is based on a heat leakage calculation for the flexible heat-insulating pipe. Generally, there are two methods for calculating the heat leakage of the heat insulating material. The first is to calculate the heat leakage of each layer of material in a multilayer heat insulating material layer by layer. The second is to calculate the radiation, convection and heat conduction of the multilayer insulation material independently and then to algebraically sum the above data. However, since the multilayer insulation material not only involves radiation, convection, and heat conduction between gas and solid, but also causes secondary influence between the radiation and the heat conduction, and since the heat leakage performance of the multilayer insulation material is easily affected by various factors such as a pretreatment process, a wrapping implementation process, and a material vacuum performance, the theoretical calculation result of the multilayer insulation material cannot well meet the requirements of actual engineering.
In practical engineering experience, the method of engineering calorimeter experiment test can be adopted to obtain the heat insulation performance of the multilayer material under high vacuum. Meanwhile, the heat of the structures such as the supporting member, the inner pipeline and the outer pipeline can be calculated based on a heat transfer theory, so that the total heat leakage quantity of the heat insulation pipe can be finally obtained.
Preferably, the dimensional parameters of the flexible thermal insulation piping obtained based on step 1 include at least: the diameter of the inner pipe and the diameter of the outer pipe of the heat insulation pipe. In one embodiment of the present invention, the stainless steel inner tube, which may be provided as the thermal insulation tube, has a diameter of 120mm, the stainless steel outer tube has a diameter of 180mm,
besides, the outer diameter of the cable formed inside the stainless steel inner pipe can be set to be 100mm when the conductor core is formed into the cable according to the design size parameters of the superconducting cable core forming cable. The welding gap of the heat insulation pipe is arranged according to the welding requirement, the protection requirement, the forming requirement and the manufacturing experience of the corrugated pipe. Wherein, the welding gap of the inner pipe can be 20mm, and the welding gap of the outer pipe can be 18 mm. In addition, the thickness of the metal net sleeve is 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 multilayer heat-insulating material into a calorimeter to obtain the heat leakage quantity of the multilayer heat-insulating material, and simulating to obtain the heat conduction quantity of the support member.
Preferably, step 2 further comprises: placing a multi-layer heat-insulating material designed in advance into a measuring cylinder of a calorimeter and a vacuum cavity outside a heat-insulating quilt; injecting a coolant into the protective canister to make a 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 quantity of the multi-layer heat-insulating materials with different models designed in advance so as to select the optimal model.
FIG. 3 is a schematic view showing the construction of a calorimeter used in the method for producing a high-vacuum multi-layer flexible heat-insulating tube 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 producing a high-vacuum multi-layer flexible heat-insulating pipe for a high-temperature superconducting cable according to the present invention. As shown in fig. 3 and 4, the interior of the calorimeter comprises a vacuum chamber 8, a measuring cylinder 9 interconnected with a flow meter 13, and a protective cylinder for introducing a refrigerant liquid and a protective cylinder filler pipe 10. The measuring cylinder 9 and the protective cylinder 11 are cylindrical and are arranged coaxially with the cylindrical housing of the calorimeter. A heat insulation quilt 12 is also arranged on the outside of the protective cylinder and the measuring cylinder.
In step 1, a plurality of different multi-layer insulating materials contemplated for use in the present invention may be sequentially applied to the insulating quilt outer layer. Liquid, such as liquid nitrogen, is added into the protective cylinder through a liquid adding pipe, 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 thus obtaining the heat leakage quantity of the multilayer heat-insulating material.
Three different multilayer heat-insulating materials are designed in advance in the invention. Three different multi-layer insulation materials, namely the first, second and third insulation units shown in fig. 2, may be referred to herein in turn as an empty composite insulation unit, a multi-layer insulation unit, a boss insulation unit. The three kinds of heat insulating materials have different layers and different laying arrangement modes.
After the heat leakage quantity of the three materials is tested, the heat leakage performance of the three multilayer heat-insulating materials can be compared.
TABLE 1 thermal insulation Performance Table for three different multilayer thermal insulation materials designed in advance
The heat leakage amount of the multilayer heat insulating material arranged in a cylindrical environment with the inner pipe diameter of 120mm and the outer pipe diameter of 180mm is measured by a heat radiator. The total heat leakage of the resulting hollow composite insulation material was 250W, the heat leakage of the multilayer insulation material was 103W, and the heat leakage of the projection insulation material was 90W. In addition, the heat transfer areas of the three materials are all equal and are all 150m2Therefore, the specific heat flows of the three materials are respectively 1.67W/m2、0.69W/m2And 0.60W/m2。
Comparing the specific heat flow parameters of the three materials shows that the thermal insulation performance of the bulge thermal insulation material is the best, the thermal insulation performance of the multilayer thermal insulation material is the second best, and the thermal insulation performance of the hollow composite thermal insulation material is the worst. Therefore, a verified insulation material can be selected for use in the insulated pipe according to the above experiment.
In addition, the heat conductivity of the support is checked in step 2. According to the invention, two different bearing configurations can be used. The first is a polytetrafluoroethylene tube with an insulating material helically wound on the outside and the second is a perforated polytetrafluoroethylene ring.
Specifically, the step 2 further comprises: the structure of the support is simulated to obtain the structural temperature and heat leakage distribution of the support. Fig. 5 is a schematic view showing a simulation of the external structural temperature and the heat conduction distribution of the support member of the polytetrafluoroethylene tube in the method for manufacturing the high-vacuum multi-layer flexible heat-insulating tube for a high-temperature superconducting cable according to the present invention. Fig. 6 is a schematic view showing a simulation of the internal structural temperature and the heat conduction distribution of the support member of the polytetrafluoroethylene tube in the method for manufacturing the high-vacuum multi-layer flexible heat-insulating tube for a high-temperature superconducting cable according to the present invention. As shown in fig. 5 and 6, the structure of the support member was simulated by simulation software commonly used in the prior art, and the temperature and heat leakage at different portions of the support member were simulated. The heat leakage of the support used in the present invention was 8.1W.
And 3, designing the internal structure of the heat-insulating pipe based on the heat-insulating requirement of the heat-insulating pipe, and evaluating the design of the internal structure of the heat-insulating pipe based on heat leakage operation.
Comparing the heat insulation requirement of the superconducting cable heat insulation pipe with the heat leakage amount of the multi-layer heat insulation material and the heat conduction amount data of the supporting member obtained in the step 2, the internal structure of the heat insulation pipe can be preliminarily designed.
Specifically, three different design methods can be adopted for the internal structure of the thermal insulation piping in the present invention. The first method is to add multiple layers of heat insulating material and glass wool between the inner and outer pipelines of the heat 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 method is to use a high vacuum multi-layer insulating flexible jacket. A plurality of layers of heat insulating materials, for example, three layers of heat insulating materials, are provided outside the inner pipe, and the space between the inner and outer pipes is sealed and evacuated to a vacuum state, and heat insulation is performed by the vacuum and the heat insulating materials. Since in the second method, a large amount of air is present in the space between the insulation material and the inner pipe and is difficult to extract by the vacuum-pumping equipment. Therefore, in the present invention, the third method is adopted. The third method is to use a high vacuum multi-layer heat insulation flexible sleeve, and the outer wall of the inner pipe is provided with projections according to a certain rule. Due to the existence of the bulges, air between the outer wall of the inner pipe and the multi-layer heat-insulating material is more easily extracted, so that the heat-insulating property of the vacuum interlayer is ensured. Therefore, the third method has a better heat insulating effect than the second method, and can improve the heat insulating efficiency by 8% to 10%, and can improve the evacuation efficiency by about 30%.
Specifically, the calculation of the heat leakage theory may be performed according to the design to evaluate the design.
Preferably, the heat leakage operation in step 3 is specifically as follows:
and 3.1, acquiring the value of the heat radiation quantity of the outer pipe in the flexible heat-insulating pipe to the inner pipe based on the materials, sizes and temperatures of the inner pipe and the outer pipe in the flexible heat-insulating pipe and the number of layers of radiation screens between the inner pipe and the outer pipe.
The calculation formula of the heat radiation quantity of the outer pipe to the inner pipe in the flexible heat insulation pipe is as follows:
wherein ε is the emissivity;
sigma is Stefan-Boltzmann constant, and has a value of 5.67 × 10-8W/(m2·K4)；
A is the surface area of the inner pipe of the flexible heat-insulating pipe;
T2for the outer tube temperature, there is T in the present example2＝300K；
T1For the inner tube temperature, there is T in the present example1＝68K；
F1-2An angular coefficient of heat transfer by radiation and having F1-2＝1；
n is the number of layers of the radiation screen, and is related to the composition of the multilayer heat insulating material.
In addition, for the parameter ε1-2The calculation formula is as follows:
wherein epsilon1And ε2Emissivity of stainless steel 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 pipe to the inner pipe in the heat-insulating pipe1＝0.132W/m。
And 3.2, acquiring the residual gas heat leakage value of the vacuum layer based on the vacuum degree of the vacuum interlayer and the sizes and the temperatures of the inner pipe and the outer pipe.
In the method, the calculation formula of the residual gas heat leakage quantity is as follows:
Q2＝k×a×p×(T2-T1)×A
(3)
wherein k is coefficient, and k is 1.2001;
a is a thermal adaptation coefficient, and a is 1;
p is interlayer vacuum degree, and in the present invention, p is 0.01 Pa.
According to the method of the present invention, Q2＝1.01W/m。
And 3.3, setting a value of the heat leakage quantity of the supporting piece.
In the invention, the value of the heat leakage of the supporting member can be set, or the value of the heat leakage of the supporting member can be approximated by a simulation method. In the present invention, the value of the amount of heat leakage of the supporting member can be set to Q3＝0.713W/m。
And 3.4, acquiring the total heat load of the heat insulation pipe based on the value of the heat radiation quantity of the outer pipe to the inner pipe, the value of the residual gas heat leakage quantity of the vacuum layer and the value of the heat leakage quantity of the supporting member.
In the present invention, the total amount of heat load of the heat-insulating pipe is calculated by the following formula:
Q＝Q1+Q2+Q3 (4)
according to the method of the present invention, the total heat load Q of the heat-insulating pipe is approximately equal to 1.9W/m.
The present invention has the advantages that, compared with the prior art, the high vacuum multi-layer flexible heat insulation pipe for high temperature superconducting cable and the manufacturing method thereof according to the present invention can reduce the contact area between the heat insulation material and the outer wall of the inner pipe through the protrusion arranged on the outer wall of the inner pipe, improve the evacuation efficiency of the vacuum interlayer, and thus ensure the heat insulation efficiency of the heat insulation pipe. The method for manufacturing the heat-insulating pipe can accurately calculate and simulate the heat leakage data of the heat-insulating pipe in different heat-insulating pipe design schemes, so as to provide powerful guarantee for the design of the heat-insulating pipe and the verification of the performance of the heat-insulating pipe.
The present applicant has described and illustrated embodiments of the present invention in detail with reference to the accompanying drawings, but it should be understood by those skilled in the art that the above embodiments are merely 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 for limiting the scope of the present invention, and on the contrary, any improvement or modification made based on the spirit of the present invention should fall within the scope of the present invention.
Claims (10)
1. A high vacuum multi-layer flexible heat insulation pipe for a high temperature superconducting cable comprises an outer pipe, an inner pipe and an interface flange, and is characterized in that:
the flexible thermal insulation piping further comprises:
a vacuum interlayer (1) located between the inner tube and the outer tube;
the multilayer heat insulation material (2) is positioned on one side, close to the outer wall of the inner pipe, in the vacuum interlayer and used for heat insulation;
the outer wall of the inner pipe is provided with a bulge (3) to reduce the contact area of the multilayer heat-insulating material and the outer wall of the inner pipe.
2. The high-vacuum multi-layer flexible heat-insulating pipe for a high-temperature superconducting cable as claimed in claim 1, wherein:
the height of the bulge on the outer wall of the inner pipe is between 3 and 5mm, and the bulge is used for reducing the contact area of the multilayer heat-insulating material and the outer wall of the inner pipe so as to improve the evacuation efficiency of the vacuum interlayer.
3. The high-vacuum multi-layer flexible heat-insulating pipe for a high-temperature superconducting cable as claimed in claim 2, wherein:
the bulges on the outer wall of the inner pipe are distributed on the outer wall of the inner pipe at equal intervals.
4. The high-vacuum multi-layer flexible heat-insulating pipe for a high-temperature superconducting cable as claimed in claim 1, wherein:
the multilayer heat insulation material comprises a plurality of layers of heat insulation units;
each layer of heat insulation unit at least comprises a reflection 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 heat-insulating pipe for a high-temperature superconducting cable as claimed in claim 1, wherein:
the vacuum interlayer of the flexible heat-insulating pipe also comprises a support (4) positioned in the middle of the pipe, a hydrogen remover (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 a hole, which is spirally wound outside the heat-insulating material.
6. The manufacturing method of high vacuum multi-layer flexible thermal insulation piping for high temperature superconducting cable as claimed in claims 1 to 5, characterized by comprising the steps of:
step 1, obtaining size parameters of a flexible heat insulation pipe for the high-temperature superconducting cable based on a liquid nitrogen flow simulation test in the corrugated pipe and design indexes of the superconducting cable;
step 2, placing the pre-designed multilayer heat-insulating material into a calorimeter to obtain the heat leakage quantity of the multilayer heat-insulating material, and simulating to obtain the heat conduction quantity of a support member;
and 3, designing the internal structure of the heat-insulating pipe based on the heat-insulating requirement of the heat-insulating pipe, and evaluating the design of the internal structure of the heat-insulating pipe based on heat leakage operation.
7. The manufacturing method of a high vacuum multi-layer flexible heat-insulating pipe for a high temperature superconducting cable as claimed in claim 6, wherein:
the dimensional parameters of the flexible thermal insulation piping obtained based on step 1 include at least: the diameter of the inner pipe and the diameter of the outer pipe of the heat insulation pipe.
8. The manufacturing method of a high vacuum multi-layer flexible heat-insulating pipe for a high temperature superconducting cable as claimed in claim 6, wherein:
the step 2 further comprises the following steps:
placing the pre-designed multilayer heat-insulating material into a measuring cylinder of a calorimeter and a vacuum cavity outside a heat-insulating quilt;
injecting a coolant into the protective canister 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 quantity of the multi-layer heat-insulating materials with different models designed in advance so as to select the optimal model.
9. The manufacturing method of a high vacuum multi-layer flexible heat-insulating pipe for a high temperature superconducting cable as claimed in claim 6, wherein:
the step 2 further comprises the following steps:
the structure of the support is simulated to obtain the structural temperature and heat leakage distribution of the support.
10. The manufacturing method of a high vacuum multi-layer flexible heat-insulating pipe for a high temperature superconducting cable as claimed in claim 6, wherein:
the heat leakage operation in the step 3 specifically includes:
step 3.1, obtaining the value of the heat radiation quantity of the inner pipe from the outer pipe in the flexible heat-insulating pipe based on the materials, the sizes and the temperatures of the inner pipe and the outer pipe in the flexible heat-insulating pipe and the number of layers of radiation screens between the inner pipe and the outer pipe;
3.2, acquiring residual gas heat leakage values of the vacuum layer based on the vacuum degree of the vacuum interlayer and the sizes and the temperatures of the inner pipe and the outer pipe;
step 3.3, setting a value of the heat leakage quantity of the supporting piece;
and 3.4, acquiring the total heat load of the heat insulation pipe based on the value of the heat radiation quantity of the outer pipe to the inner pipe, the value of the residual gas heat leakage quantity of the vacuum layer and the value of the heat leakage quantity of the supporting member.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| 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 |
| 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 |
| 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 |
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| Application Number | Priority Date | Filing Date | Title |
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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 |
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| CN113393971A true CN113393971A (en) | 2021-09-14 |
| CN113393971B CN113393971B (en) | 2023-04-28 |
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| Country | Link |
|---|---|
| CN (1) | CN113393971B (en) |
| AU (1) | AU2021338587B2 (en) |
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|---|---|---|---|---|
| WO2022267417A1 (en) * | 2021-06-24 | 2022-12-29 | 国网上海市电力公司 | High-vacuum multi-layer flexible thermal insulation tube for high-temperature superconducting cable and fabrication method |
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Also Published As
| Publication number | Publication date |
|---|---|
| AU2021338587B2 (en) | 2023-08-10 |
| AU2021338587A1 (en) | 2023-01-19 |
| CN113393971B (en) | 2023-04-28 |
| WO2022267417A1 (en) | 2022-12-29 |
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