A device and method for testing magnetic field angle dependence and torsion of high-temperature superconducting tape

Abstract

The present invention belongs to the technical field of high-temperature superconductivity, and specifically relates to a device and method for testing the angle dependence and torsion of a magnetic field of a high-temperature superconducting tape. In the present invention, an upper support plate is connected to a lower support plate, a lower rotating table is fixed at the center of the lower support plate, an upper rotating table is installed at the center of the upper support plate, a circular arc opening is opened on the upper support plate, and the upper rotating table and the lower rotating table are connected by a connecting rod; a lower pressing plate and an upper pressing plate are respectively installed on the top of the lower rotating table and the bottom of the upper rotating table; a fixed rod is installed on the upper rotating table and is located above the upper support plate, and a lower current lead is L-shaped, one end is fixed on the lower rotating table, and the other end passes through the opening of the upper support plate and is fixed on the fixed rod or the fixed block; a triangular pull rod is installed on the lower surface of the upper support plate, and a background field magnet is fixedly connected to the upper support plate through the triangular pull rod. The present invention is used to test the angle dependence of a superconducting tape under an external magnetic field and the influence of tape torsion on the critical current.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature superconductivity, and in particular relates to a device and method for testing the angle dependence and torsion of a high-temperature superconducting tape magnetic field. Background Art

[0002] When the temperature drops to a certain level, the resistance of the material suddenly becomes zero or disappears. This phenomenon is called superconductivity, and the temperature at this time is called the critical transition temperature (T c ). Currently, it is usually T c = 30K is the dividing line between low temperature superconductivity and high temperature superconductivity, T c <30K is low temperature superconductivity, T c ≥30K is high temperature superconductivity.

[0003] With the rapid development of high-temperature superconducting materials, the second-generation REBCO high-temperature superconducting tapes have great application prospects in the fields of energy, electricity, medicine and military industry due to their high operating temperature, current carrying capacity and critical magnetic field, and have been widely used in these fields.

[0004] Compared with conventional wires, the critical current of high-temperature superconducting tape is one of the important indicators for judging its quality. High-temperature superconducting tape is made of different materials stacked on top of each other, such as superconducting layer, substrate layer, buffer layer and copper layer. The coherence length and penetration depth in each direction have different values, so high-temperature superconductivity has obvious anisotropy. In terms of macroscopic electromagnetic performance, it is reflected in the fact that the tape has different critical current characteristics under magnetic fields of different amplitudes and angles.

[0005] At the same time, when high-temperature superconducting tapes are used to prepare cables, conductors or magnets, the tapes will inevitably undergo corresponding twisting, which will have a certain impact on the current-carrying capacity (critical current) of the superconducting tapes, causing their critical current to decrease, thereby affecting the normal operation of related superconducting devices.

[0006] The angular dependence of high-temperature superconducting tapes under external magnetic fields and the effect of torsion on critical current are essential parameters in the design and application of superconducting magnets, cables or conductors. Existing technologies can only test the angular dependence of high-temperature superconducting tapes under background fields of different sizes, but cannot simultaneously test the critical performance of the tapes under torsion, let alone test the angular dependence of high-temperature superconducting tapes with different torques under different background fields; or can only test the critical current under torsion of the tape, but cannot test the effect of background field changes on the critical current. Summary of the invention

[0007] The purpose of the present invention is to provide a REBCO high-temperature superconducting tape magnetic field angle dependence and torsion testing device in a liquid nitrogen environment, which is used to test the angle dependence of the superconducting tape under an external magnetic field and the influence of the tape torsion on the critical current, thereby providing a more reliable experimental basis for the design and manufacture of high-temperature superconducting magnets, cables or conductors.

[0008] The technical solution adopted by the present invention is:

[0009] A high-temperature superconducting strip magnetic field angle dependence and torsion test device, comprising an upper support plate, a lower support plate, an upper rotating platform, a lower rotating platform, a lower current lead, a lower pressing plate, an upper pressing plate, a fixing rod, and a background magnet; the upper support plate and the lower support plate are connected and fixed by support rods and nuts, the lower rotating platform is fixed to the center of the lower support plate by screws, the upper rotating platform is installed at the center of the upper support plate, a circular arc opening is opened on the upper support plate, the upper rotating platform and the lower rotating platform are connected by a connecting rod to ensure rigid rotation during the angle dependence measurement of the strip; the lower pressing plate is fixed to the center of the lower support plate by screws, the upper rotating platform is installed at the center of the upper supporting plate, a circular arc opening is opened on the upper supporting plate, and the upper rotating platform and the lower rotating platform are connected by a connecting rod to ensure rigid rotation during the angle dependence measurement of the strip; the lower pressing plate is fixed to the center of the lower support plate by screws, and the upper rotating platform is fixed to the center of the lower support plate by screws. The sheet and the upper pressing sheet are respectively installed on the top of the lower rotating table and the bottom of the upper rotating table, and are used to fix the strip sample; the fixing rod is installed on the upper rotating table and is located above the upper supporting plate; the lower current lead is L-shaped, one end of which is fixed on the lower rotating table, and the other end passes through the opening of the upper supporting plate and is fixed on the fixing rod during angle dependence measurement; a fixing block is installed on the upper supporting plate, and the other end of the lower current lead is fixed on the fixing block during torsion test; a triangular pull rod is installed on the lower surface of the upper supporting plate, and the background field magnet is fixedly connected to the upper supporting plate through the triangular pull rod.

[0010] In angle-dependent measurements, the lower current lead moves in a circular open track as the rotation angle changes.

[0011] A rotating rod is installed on the upper rotating platform, and the upper current lead is installed in the central opening on the top of the upper rotating platform and is tightly matched with the opening.

[0012] A scale plate is installed at the center of the upper support plate and at a position that coincides with the center opening, and the scale plate is used to mark angle changes during testing.

[0013] The background field magnet is composed of a self-made separated high-temperature superconducting coil. The symmetrical central area of ​​the separated magnet can form a certain magnetic field uniformity area after power is turned on for measuring the magnetic field angle dependence.

[0014] The materials of the upper supporting plate, the lower supporting plate, the upper rotating platform, the lower rotating platform, the fixing rod, the fixing block, the lower pressing sheet and the upper pressing sheet are insulating epoxy resin.

[0015] The connecting rod material is non-magnetic aluminum alloy, which can avoid measurement errors caused by magnetization after power is turned on.

[0016] A method for testing the magnetic field angle dependence and torsion of a high temperature superconducting tape comprises the following steps:

[0017] Step 1: Low temperature marking of the magnetic field size in the uniform area of ​​the background magnet and recording the current size required for different magnetic field strengths;

[0018] Step 2: Angle dependence test of the strip under external magnetic field:

[0019] Step 2.1: Install the high-temperature superconducting tape sample on the current leads of the upper rotating table and the upper rotating table through the lower pressing plate and the upper pressing plate, ensure that both ends of the sample are in good contact with the lower current lead and the upper current lead respectively, and make the tape have a certain tensile stress and be in a vertical state;

[0020] Step 2.2: Lead out the voltage lead at a certain position away from the two ends of the crimping point between the sample and the current lead, insert the lower end of the connecting rod connecting the upper rotating stage and the lower rotating stage into the groove of the lower rotating stage and fix the upper end on the upper rotating stage;

[0021] Step 2.3: Connect the power line to the lower current lead and the upper current lead, place it in the liquid nitrogen dewar and cool it to the superconducting state; manually rotate the rotating rod to make the sample strip at the specified magnetic field angle;

[0022] Step 2.4: The current source energizes the background field magnet to a specified magnetic field to obtain a uniform magnetic field. At this time, the strip sample is energized through the power cord to start the test;

[0023] Step 3: Torsion Test

[0024] After step 2.4 is completed, lift the test part out of the Dewar, fix the lower rotating table and remove the connecting rod, and re-fix the lower current lead on the fixed block. When completed, put it back into the Dewar and repeat step 2.4.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention provides a high-temperature superconducting tape angle dependence and torsion testing device and method, which provides a uniform magnetic field through a high-temperature superconducting split magnet, and places the high-temperature superconducting tape in the uniform field, and uses a four-lead method and control of the magnetic field size to achieve the influence of the magnetic field angle of the tape or the critical current change of the tape under different external magnetic fields.

[0027] (2) The present invention provides a device and method for testing the angle dependence and torsion of a high-temperature superconducting tape. The magnetic field direction of the background magnet homogeneous zone is perpendicular to the placed test sample, which makes it easy to adjust the angle between the magnetic field and the tape surface, and is conducive to testing the influence of the vertical field on the tape performance.

[0028] (3) The present invention provides a device and method for testing the angle dependence and torsion of a high-temperature superconducting tape. In the separation gap of the background magnet, the REBCO high-temperature superconducting tape can rotate with the connecting rod within the range of 0 to 180 degrees, and the magnetic field angle dependence test is achieved by changing the angle between the tape surface and the magnetic field.

[0029] (4) The present invention provides a device and method for testing the angle dependence and torsion of a high-temperature superconducting tape. The present invention can not only test the angle dependence of a high-temperature superconducting tape under different external fields, but also test the effect of torsion on the critical current of the tape in the presence or absence of a magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the structure of a high-temperature superconducting tape magnetic field angle dependence and torsion testing device provided by the present invention;

[0031] Figure 2 An isometric view of the components used for strip sample fixing and energization testing is shown;

[0032] Figure 3 The four-lead measurement principle of the device of the present invention is shown;

[0033] In the figure: 1-upper support plate, 2-lower support plate, 3-support rod, 4-upper rotating table, 5-lower rotating table, 6-rotating rod, 7-lower current lead, 8-upper current lead, 9-lower pressing sheet, 10-upper pressing sheet, 11-fixing rod, 12-magnet triangular pull rod, 13-connecting rod, 14-background magnet, 15-fixing block, 16-dial. DETAILED DESCRIPTION

[0034] The following is a further detailed description of a high-temperature superconducting tape magnetic field angle dependence and torsion testing device and method provided by the present invention in conjunction with the accompanying drawings and specific embodiments.

[0035] like Figure 1 As shown, a specific embodiment of the present invention is a high-temperature superconducting tape magnetic field angle dependence and torsion test device, comprising: an upper support plate 1, a lower support plate 2, an upper rotating table 4, a lower rotating table 5, a lower current lead 7, a fixing rod 11, and a background magnet 14;

[0036] The upper support plate 1 and the lower support plate 2 are connected and fixed by the support rod 3 and the nut. The lower support plate 2 has an opening in the center for installing the lower rotating table 5. The lower rotating table 5 is fixed on the lower support plate 2 by screws for torsion test of the strip. The upper support plate 1 also has an opening in the center for installing the upper rotating table 4. The upper support plate 1 has a 185° arc opening, such as Figure 2As shown, the upper rotating table 4 and the lower rotating table 5 are connected by a connecting rod 13 to ensure the rigid rotation during the angle dependence measurement of the strip; the lower pressing plate 9 and the upper pressing plate 10 are respectively installed on the top of the lower rotating table 5 and the bottom of the upper rotating table 4, and are used to fix the strip sample; the fixing rod 11 is installed on the upper rotating table 4 and is located above the upper support plate 1, the lower current lead 7 is L-shaped, one end of which is fixed to the lower rotating table 5 by a screw, and the other end passes through the opening of the upper support plate 1 and is fixed to the fixing rod 11 during the angle dependence measurement. During the angle dependence measurement, the lower current lead 7 moves in the circular arc track as the rotation angle changes; a rotating rod 6 is installed on the upper part of the upper rotating table 4, and the upper current lead 8 is installed in the central opening on the top of the upper rotating table 4 and fits tightly with its opening.

[0037] A fixing block 15 is mounted on the upper support plate 1. During the torsion test, the other end of the lower current lead 7 is fixed on the fixing block 15.

[0038] The lower rotating table 5 has grooves and screw holes for fixing the lower current lead 7, and the grooves connecting the upper rotating table 4 and the pressing plate 9 and screw holes for fixing the superconducting tape; the dial 16 is used to mark the angle change during testing, and is installed at the center position of the upper support plate 1 and coincides with the center opening.

[0039] A triangular tie rod 12 is installed on the lower surface of the upper support plate 1, and a background field magnet 14 is fixedly connected to the upper support plate 1 through the triangular tie rod 12. The background field magnet 14 is composed of a homemade separated high-temperature superconducting coil. The symmetrical center area of ​​the separated magnet can form a certain magnetic field uniformity area after power is turned on for measuring the angle dependence of the magnetic field.

[0040] The material of the upper support plate 1, the lower support plate 2, the upper rotating platform 4, the lower rotating platform 5, the fixing rod 11, the fixing block 15, the lower pressing plate 9 and the upper pressing plate 10 is insulating epoxy resin.

[0041] The material of the connecting rod 13 is non-magnetic aluminum alloy, which can avoid measurement errors caused by magnetization after power is turned on.

[0042] The scale 16 of the dial is 0 to 360 degrees, and the smallest scale is 1 degree.

[0043] A method for magnetic field angle dependence and torsion testing, comprising the following steps:

[0044] Step 1: Before the first use, use the Hall sensor probe to mark the magnetic field size of the uniform area of ​​the background magnet 14 with low temperature (liquid nitrogen), and record the current size required for different magnetic field strengths. This is to facilitate the background magnetic field size under the specified current during testing.

[0045] Angle dependence test of strip under external magnetic field:

[0046] Step 2: Install the REBCO high-temperature superconducting tape sample on the current leads of the upper rotating table 4 and the upper rotating table 5 through the lower pressing plate 9, the upper pressing plate 10 and the screws, ensuring that the two ends of the sample are respectively pressed against the lower current lead 7 and the upper current lead 8 (good contact) and that the tape has a certain tensile stress and is in a vertical state.

[0047] Step 3: Draw out the voltage lead at a certain distance from the sample and the current lead crimping point. Figure 3 As shown, the lower end of the connecting rod 13 connecting the upper rotating platform 4 and the lower rotating platform 5 is inserted into the groove of the lower rotating platform 5 and the upper end is fixed on the upper rotating platform 4.

[0048] Step 4: After the above steps are completed, the power line is connected to the lower current lead 7 and the upper current lead 8, and it is placed in the liquid nitrogen dewar and cooled to the superconducting state. Then, by manually rotating the rotating rod 6, the sample strip is placed at a specified magnetic field angle.

[0049] Step 5: The current source energizes the background field magnet 14 to the specified magnetic field to obtain a uniform magnetic field. At this time, the strip sample is energized through the power cord to start the test. During the test, the angle between the strip and the magnetic field is adjusted by rotating the rod 6 according to the test angle requirements for measurement (the angle is determined by the dial 16). After testing a specified background field data, the magnetic field size of the background field magnet 14 can be adjusted to measure the next set of data.

[0050] Torsion test:

[0051] Step 6: If only the strip needs to be subjected to torsion or torsion test under magnetic field, it can be carried out as described in steps 2 to 5. It should be noted that the step of using the connecting rod 13 in step 3 is not required here; in addition, the lower rotating table 5 needs to be fixed on the lower support plate 2, and the upper end of the lower current lead 7 needs to be fixedly connected to the fixing block 15 on the upper support plate 1.

[0052] Step 7: If it is necessary to first test the angle dependence of the strip under an external field and then test its torsion or the critical current of torsion under an external field, after completing step 5, the test part can be taken out of the Dewar tank, the lower rotating table 5 can be fixed and the connecting rod 13 can be removed, and the lower current lead 7 can be re-fixed on the fixed block 15. After completion, put it back into the Dewar and execute according to step 5.

[0053] In particular, the angle-dependent performance under the external magnetic field can meet the test of 0 to 180 degrees, and the strip torsion test can meet the test of any angle.

[0054] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the art who, within the technical scope disclosed by the present invention, makes equivalent substitutions or changes based on the technical scheme and inventive concept of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for testing the angle dependence and torsion of a high-temperature superconducting tape magnetic field, based on a high-temperature superconducting tape magnetic field angle dependence and torsion testing device, comprising an upper support plate (1), a lower support plate (2), an upper rotating platform (4), a lower rotating platform (5), a lower current lead (7), a lower pressing plate (9), an upper pressing plate (10), a fixing rod (11), and a background field magnet (14); the upper support plate (1) and the lower support plate (2) are connected and fixed by a support rod (3) and a nut, the lower rotating platform (5) is fixed to the center of the lower support plate (2) by screws, the upper rotating platform (4) is installed at the center of the upper support plate (1), and the upper support plate (1) has an arc opening, and the upper rotating platform (4) and the lower rotating platform (5) are connected by a connecting rod (13) to ensure rigid rotation during the angle dependence measurement of the strip; the lower pressing plate (9) and the upper pressing plate (10) are respectively installed on the top of the lower rotating platform (5) and the bottom of the upper rotating platform (4) to fix the strip sample; the fixing rod (11) is installed on the upper rotating platform (4) and is located above the upper support plate (1); the lower current lead (7) is L-shaped, one end of which is fixed on the lower rotating platform (5), and the other end passes through the opening of the upper support plate (1) and is fixed on the fixing rod (11) during the angle dependence measurement; A fixing block (15) is installed, and during a torsion test, the other end of the lower current lead (7) is fixed on the fixing block (15); a triangular pull rod (12) is installed on the lower surface of the upper support plate (1), and the background field magnet (14) is fixedly connected to the upper support plate (1) through the triangular pull rod (12); during angle dependence measurement, the lower current lead (7) moves in a circular arc opening track as the rotation angle changes; a rotating rod (6) is installed on the upper part of the upper rotating platform (4), and the upper current lead (8) is installed in the central opening at the top of the upper rotating platform (4) and is tightly matched with the opening; the central position of the upper support plate (1) is aligned with the central opening A scale plate (16) is installed at the hole overlap position, and the scale plate (16) is used to mark the angle change during testing; the background field magnet (14) is composed of a self-made separated high-temperature superconducting coil, and the symmetrical central area of ​​the separated magnet can form a certain magnetic field uniform area after power is turned on for measuring the magnetic field angle dependence; the upper support plate (1), the lower support plate (2), the upper rotating table (4), the lower rotating table (5), the fixed rod (11), the fixed block (15), the lower pressing plate (9), and the upper pressing plate (10) are made of insulating epoxy resin; the connecting rod (13) is made of non-magnetic aluminum alloy, which can avoid measurement errors caused by magnetization after power is turned on. Features: The steps include: Step 1: Low temperature marking of the magnetic field size in the uniform area of ​​the background field magnet (14) and recording the current size required for different magnetic field strengths; Step 2: Angle dependence test of the strip under external magnetic field: Step 2.1: Mount the high-temperature superconducting tape sample on the current leads of the upper rotating table (4) and the lower rotating table (5) through the lower pressing plate (9) and the upper pressing plate (10), ensuring that both ends of the sample are in good contact with the lower current lead (7) and the upper current lead (8) respectively, and that the tape has a certain tensile stress and is in a vertical state; Step 2.2: Lead out the voltage lead at a certain position away from the two ends of the crimping point between the sample and the current lead, insert the lower end of the connecting rod (13) connecting the upper rotating table (4) and the lower rotating table (5) into the groove of the lower rotating table (5) and fix the upper end on the upper rotating table (4); Step 2.3: Connect the power line to the lower current lead (7) and the upper current lead (8), place it in a liquid nitrogen dewar and cool it to a superconducting state; manually rotate the rotating rod (6) to place the sample strip at a specified magnetic field angle; Step 2.4: The current source energizes the background field magnet (14) to a specified magnetic field to obtain a uniform magnetic field, and then the strip sample is energized through the power line to start testing; Step 3: Torsion Test After step 2.4 is completed, lift the test part out of the Dewar, fix the lower rotating table (5) and remove the connecting rod (13), and re-fix the lower current lead (7) on the fixing block (15). After completion, put it back into the Dewar and repeat step 2.4.

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