An apparatus, method and application for multilayer strand ice adhesion strength testing

Abstract

The present application belongs to the technical field of anti-icing, and particularly relates to a device and method for testing ice adhesion strength of multi-layered stranded wire and application. The present application firstly provides a device for testing ice adhesion strength of multi-layered stranded wire with complex structure, which fully considers the complex structural characteristics of the multi-layered stranded wire and can simulate different icing environment conditions to freeze the stranded wire to be tested, thereby filling the gap in the industry. Secondly, the present application provides a method for testing ice adhesion strength of stranded wire based on the device for testing ice adhesion strength, which not only provides a method for testing and calculating ice adhesion strength by using a sensor, but also provides a judgment method for further confirming the ice adhesion strength value based on the residual ice area on the surface of the stranded wire. Therefore, the result has high reliability and overcomes the problem that the result of testing ice adhesion strength of stranded wire by using an instrument is not completely accurate.

Description

Technical Field

[0001] This invention belongs to the field of anti-icing technology, specifically relating to a device, method, and application for testing the ice adhesion strength of multilayer stranded wires. Background Technology

[0002] Component icing, also known as glazing, refers to the natural phenomenon of water freezing on the surface of components. Component icing is a natural disaster, as seen in aircraft icing in the aviation industry, cable icing in the energy and power sector, and wind turbine icing. In the energy and power sector, icing of transmission lines leads to the superposition of the weight of the ice layer and wind load. If the ice adhesion strength exceeds the conductor's bearing capacity (usually greater than 500 kPa), it can cause accidents such as line breaks and tower collapses. There are three common forms of component icing: precipitation icing, cloud icing, and sublimation icing. Precipitation icing, typically formed by freezing rain and accumulated water freezing, creates a dense icing structure that poses a significant hazard. The construction of my country's planned new power systems will inevitably pass through (ultra)high altitude, heavily iced areas. The adhesion strength between ice and other materials is a crucial indicator for evaluating the effectiveness of anti-icing measures. Therefore, accurately and efficiently testing the ice adhesion strength of equipment icing is of great significance.

[0003] The mainstream methods for testing ice adhesion strength currently include the shear method and the centrifugal method. In the shear method, water is typically injected into the frozen area of ​​the testing device to contact the substrate material, followed by static freezing. The ice is then separated from the substrate material by a traction platform or by applying a load parallel to the substrate material, thus completing the adhesion test. In the centrifugal method, the ice is rotated at a constant acceleration along the axial direction of the testing device. Since the centrifugal force is greater than the adhesion force between the ice and the substrate material, the ice detaches from the substrate surface, and the adhesion force adhering to the workpiece is calculated from the rotation speed. The literature "Ice Adhesion Force Test and Influencing Factor Analysis" discloses a method for measuring the adhesion force between ice and the substrate material using the direct shear method. This literature mainly focuses on testing the ice adhesion force of flat structures made of aluminum, iron, copper, and stainless steel, and does not provide any guidance on testing methods for non-flat materials. Furthermore, while testing methods for ice adhesion strength of materials with flat structures such as aluminum plates are relatively well-established, there are few reports on methods for testing complex multilayer stranded wires. The mainstream method of directly measuring the adhesion force between the ice layer and the substrate material cannot provide accurate guidance on the ice adhesion strength of multilayer stranded wires. This is because multilayer stranded wires often experience ice interlocking in actual applications, and existing ice adhesion strength testing methods can often only detect surface ice.

[0004] In addition, existing testing technologies also have the problem of mismatch between the accuracy of test results and the adaptability of scenarios. That is, many existing test data are based on an ideal model condition, which deviates from the actual application scenario. For example, it is manifested in: (1) poor data reliability: the calculated ice area deviates from the estimated ice area, and the ice thickness cannot be accurately quantified (e.g., CN 102628789 A); due to the large error caused by different pushing rates, the use of manual ice pushing without specifying the pushing rate of the automatic device will lead to inaccurate final results and poor repeatability (e.g., CN 102269691A). (2) crude ice control: the same mold is not used, and the contact area of ​​the same volume of water droplet and the test surface is completely different for materials with different contact angles (especially superhydrophobic materials), which ultimately leads to the uncontrollable size and shape of ice (e.g., CN102269691A). (3) Mechanical loading interference: The traditional centrifugal peeling method causes the internal cracks of the ice layer to expand due to high-speed rotation, and the measured value deviates from the true interface bonding strength; the impregnation and drawing method inevitably forms ice-to-ice connections due to the space left in the aluminum stranded wire. When measuring the maximum pulling force, in addition to the ice-solid adhesion force, there is also a large amount of ice-ice bonding force (such as CN114878457A). (4) Vague parameter definition: International standards (such as SAE ARP 5485) do not clearly define the physical boundary of "ice adhesion strength" (such as interface failure criteria, ice layer cohesion failure compensation method).

[0005] In conclusion, in order to accurately test the ice adhesion strength of multilayer stranded wires and correctly evaluate their anti-icing performance, new methods and strategies are urgently needed to fill the gaps in the industry. Summary of the Invention

[0006] The purpose of this invention is to provide a device and evaluation method for testing the ice adhesion strength of conductors, which partially solves or alleviates the above-mentioned deficiencies in the prior art. The invention specifically adopts the following technical solution.

[0007] One aspect of this invention is to provide a method for testing the ice adhesion strength of multilayer stranded wires.

[0008] A method for evaluating the ice adhesion strength of multilayer stranded wire, the method comprising (directly) testing the ice adhesion strength on the surface of the multilayer stranded wire and evaluating the ice adhesion strength test results based on the residual ice area on the surface of the multilayer stranded wire (evaluating the reliability of the directly tested ice adhesion strength). The multilayer stranded wire ice adhesion strength test is conducted based on an ice adhesion strength test device, which includes a stranded wire placement mold (10), a freezing box (20), a thrust sensor (30), and an experimental platform (40). The strand placement mold (10) is a cubic structure with a semi-circular groove on its surface for placing the strand to be tested. The size of the semi-circular groove is designed to be slightly larger than the diameter of the strand to be tested so that it is not easy to slide. The experimental platform (40) includes a flat plate (41) with movable double rails and a lifting platform (42). The strand placement mold (10) is placed on the lifting platform (42). The freezing box (20) is placed on the flat plate (41) of the experimental platform (40) for freezing the stranded wire to be tested; an insertion hole (21) is provided on the side of the freezing box (20) for the metal push rod (31) of the thrust sensor (30) to be inserted during the test. During testing: S01: Fix the multi-layer stranded wire to be tested on the flat plate (41); place the stranded wire placement mold (10) on the lifting platform (42), and adjust the height of the lifting platform (42) so that the stranded wire placement mold (10) is in close contact with the multi-layer stranded wire to be tested; S02: Add liquid to the stranded wire placement mold (10) and control the highest liquid level H1 and the lowest liquid level H2; H1 is the liquid level height that covers the outermost strand of the multi-layer stranded wire to be tested; H2 is the liquid level height that can wet the outermost strand of the multi-layer stranded wire to be tested. S03: Set the freezing chamber (20) according to the predetermined temperature, humidity and time to freeze the multilayer stranded wire to be tested and the stranded wire placement mold (10). After freezing, insert the metal push rod (31) of the thrust sensor (30) into the insertion hole (21) and adjust the position so that when the metal push rod (31) is inserted into the freezing mold, the rod head is less than or equal to 5 mm below the ice solidification interface. S04: Move the metal push rod (31) along a direction parallel to the longitudinal direction of the multi-layer stranded wire to be tested, set the push rod speed to 0.05~0.5 mm / s to start the test, and when the stranded wire placement mold (10) is completely detached from the multi-layer stranded wire to be tested, read the maximum value F of the thrust sensor (30); calculate the area of ​​residual ice marks on the stranded wire placement mold (10) to obtain the ice adhesion strength σ of the multi-layer stranded wire to be tested; σ = 1000 F / A; Where A represents the area of ​​the remaining ice mark; A=a(1-(2arccos(d / D)) / 360°)xy; Where a represents the number of outermost single filaments, D represents the overall diameter of the stranded wire, d represents the diameter of a single filament in the stranded wire, and x and y represent the length and width of the ice mark area in the mold. S05: (Using an image processing program) Calculate the residual ice mark area on the multilayer stranded wire to be tested, and set the residual ice mark area to level I, level II or level III; evaluate the ice adhesion strength σ value based on the residual ice mark area level (specifically, evaluate whether the ice adhesion strength σ can be adopted based on the residual ice mark area level).

[0009] In some specific embodiments, H1 is less than or equal to 6.06 mm; H2 is greater than or equal to 6.024 mm.

[0010] Furthermore, Level I residual ice area represents less than 10% of the stranded wire; Level II residual ice area represents 10% to 80% of the stranded wire; and Level III residual ice area represents more than 80% of the stranded wire.

[0011] Furthermore, when the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is classified as Grade I, and the result of determining the ice adhesion strength is acceptable. When the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is grade II or III, and the result of judging the ice adhesion strength is not accepted. When the ice adhesion strength σ is 21~100kPa, the residual ice mark area is Grade I, and the result of the ice adhesion strength determination can be adopted. When the ice adhesion strength σ is 21~100kPa, the residual ice mark area is Grade II or III, and the result of judging the ice adhesion strength is not accepted. When the ice adhesion strength σ is 10~20kPa, and the area of ​​the residual ice mark is of level I, II or III, the result of determining the ice adhesion strength can be adopted. When the ice adhesion strength σ is less than 10 kPa, and the area of ​​the residual ice mark is classified as Grade I, Grade II, or Grade III, the result of determining the ice adhesion strength can be adopted.

[0012] Furthermore, the freezing box (20) is also provided with multiple entrances (22) with height differences.

[0013] Furthermore, the multi-layer stranded wire to be tested is fixed on the plate (41) by a clamp (50); the clamp fixing part (51) of the clamp (50) is a disc-like structure with a round hole in the middle for fixing the multi-layer stranded wire to be tested; the clamp fixing part (51) is also provided with multiple bolt inlets (53) for inserting bolts for fastening; the clamp (50) is fixed on the track of the plate (41) by a clamp support part (52).

[0014] Furthermore, the height of the circular hole on the clamp fixing member (51) is set to be basically consistent with the height of the insertion hole (21) on the freezing box (20).

[0015] Furthermore, when used to simulate frost, the temperature of the freezing chamber (20) is set to -10℃ ~ -5℃ and the humidity is not less than 80%RH; or, when used to simulate frost, the temperature of the freezing chamber (20) is set to less than -10℃ and the humidity is less than 50%RH.

[0016] Another aspect of the present invention is to provide an apparatus for testing the ice adhesion strength of multilayer stranded wires.

[0017] An apparatus for testing the ice adhesion strength of multilayer stranded wire, the apparatus comprising a stranded wire placement mold (10), a freezing chamber (20), a thrust sensor (30), and an experimental platform (40). The stranded wire placement mold (10) is a cubic structure with a semi-circular groove on its surface for placing the wire to be tested. The size of the semi-circular groove is designed to be slightly larger than the diameter of the stranded wire to be tested so that it is not easy to slip. The experimental platform (40) includes a flat plate (41) with movable double tracks and a lifting platform (42); the strand placement mold (10) is placed on the lifting platform (42). The freezing box (20) is placed on the flat plate (41) of the experimental platform (40) for freezing the multilayer stranded wire to be tested; an insertion hole (21) is provided on the side of the freezing box (20) for the metal push rod (31) of the thrust sensor (30) to be inserted during the test. The device also includes a clamp (50) for fixing the multi-layer stranded wire to be tested onto a flat plate (41); the clamp fixing part (51) of the clamp (50) is a disc-like structure with a round hole in the middle for fixing the multi-layer stranded wire to be tested; the clamp fixing part (51) is also provided with multiple bolt inlets (53) for inserting bolts; the clamp (50) is fixed on the track of the flat plate (41) by a clamp support (52).

[0018] Furthermore, the height of the circular hole on the clamp fixing member (51) is set to be basically consistent with the height of the insertion hole (21) on the freezing box (20).

[0019] Furthermore, the freezing box (20) is connected to an external power device to circulate the freezing liquid or cold air within the box.

[0020] In another aspect, the present invention can also provide specific applications of the above-described method.

[0021] Application of multilayer stranded wires with acceptable ice adhesion strength results obtained by the above method in the preparation of anti-icing conductors.

[0022] Specifically, using the method described above for testing the ice adhesion strength of multilayer stranded wires, the ice adhesion strength of various multilayer stranded wires with super-lubricated or super-hydrophobic surfaces is tested in the laboratory under simulated outdoor icing conditions. Multilayer stranded wires with acceptable ice adhesion strength results are selected for actual outdoor anti-icing applications.

[0023] On the other hand, the present invention can also provide a method for screening stranded wires that have anti-icing properties outdoors.

[0024] A method for screening stranded wires with anti-icing properties for outdoor use, the method comprising screening stranded wires (for actual outdoor use) whose ice adhesion strength test results are acceptable under laboratory conditions. The ice adhesion strength test is conducted using an ice adhesion strength testing device, which includes a stranded wire placement mold (10), a freezing chamber (20), a thrust sensor (30), and an experimental platform (40). The strand placement mold (10) is a cubic structure with a semi-circular groove on its surface for placing the strand to be tested. The size of the semi-circular groove is designed to be slightly larger than the diameter of the strand to be tested so that it is not easy to slide. The experimental platform (40) includes a flat plate (41) with movable double rails and a lifting platform (42). The strand placement mold (10) is placed on the lifting platform (42). The freezing box (20) is placed on the flat plate (41) of the experimental platform (40) for freezing the stranded wire to be tested; an insertion hole (21) is provided on the side of the freezing box (20) for the metal push rod (31) of the thrust sensor (30) to be inserted during the test. During testing: S01: Fix the multi-layer stranded wire to be tested on the flat plate (41); place the stranded wire placement mold (10) on the lifting platform (42), and adjust the height of the lifting platform (42) so that the stranded wire placement mold (10) is in close contact with the multi-layer stranded wire to be tested; S02: Add liquid to the stranded wire placement mold (10) and control the highest liquid level H1 and the lowest liquid level H2; H1 is the liquid level height that covers the outermost strand of the multi-layer stranded wire to be tested; H2 is the liquid level height that can wet the outermost strand of the multi-layer stranded wire to be tested. S03: Set the freezing chamber (20) according to the predetermined temperature, humidity and time to freeze the multilayer stranded wire to be tested and the stranded wire placement mold (10). After freezing, insert the metal push rod (31) of the thrust sensor (30) into the insertion hole (21) and adjust the position so that when the metal push rod (31) is inserted into the freezing mold, the rod head is less than or equal to 5 mm below the ice solidification interface. S04: Move the metal push rod (31) along a direction parallel to the longitudinal direction of the multi-layer stranded wire to be tested, set the push rod speed to 0.05~0.5 mm / s to start the test, and when the stranded wire placement mold (10) is completely detached from the multi-layer stranded wire to be tested, read the maximum value F of the thrust sensor (30); calculate the area of ​​residual ice marks on the stranded wire placement mold (10) to obtain the ice adhesion strength σ of the multi-layer stranded wire to be tested; σ = 1000 F / A; Where A represents the area of ​​the remaining ice mark; A=a(1-(2arccos(d / D)) / 360°)xy; Where a represents the number of outermost single filaments, D represents the overall diameter of the stranded wire, d represents the diameter of a single filament in the stranded wire, and x and y represent the length and width of the ice mark area in the mold. S05: (Using an image processing program) Calculate the residual ice mark area on the multilayer stranded wire to be tested, and set the residual ice mark area to level I, level II or level III; evaluate whether the ice adhesion strength σ can be adopted based on the residual ice mark area level.

[0025] Furthermore, Level I residual ice area represents less than 10% of the stranded wire; Level II residual ice area represents 10% to 80% of the stranded wire; and Level III residual ice area represents more than 80% of the stranded wire.

[0026] Furthermore, the evaluation rules are as follows: When the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is classified as Level I, and the result of determining the ice adhesion strength is acceptable. When the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is grade II or III, and the result of judging the ice adhesion strength is not accepted. When the ice adhesion strength σ is 21~100kPa, the residual ice mark area is Grade I, and the result of the ice adhesion strength determination can be adopted. When the ice adhesion strength σ is 21~100kPa, the residual ice mark area is Grade II or III, and the result of judging the ice adhesion strength is not accepted. When the ice adhesion strength σ is 10~20kPa, and the area of ​​the residual ice mark is of level I, II or III, the result of determining the ice adhesion strength can be adopted. When the ice adhesion strength σ is less than 10 kPa, and the area of ​​the residual ice mark is classified as Grade I, Grade II, or Grade III, the result of determining the ice adhesion strength can be adopted.

[0027] Beneficial technical effects: This invention first provides a device for testing the ice adhesion strength of multi-layer stranded wires with complex structures. The device is designed to fully consider the complex structural characteristics of multi-layer stranded wires and can simulate different icing environmental conditions to freeze the stranded wires under test, filling a gap in the industry. Secondly, this invention provides a method for testing the ice adhesion strength of stranded wires based on this device. This method, combined with the structural features of the device, involves pushing ice onto the surface of the stranded wire, reading the ice-pushing reading, and then calculating the ice adhesion strength on the stranded wire surface. However, this invention not only provides a method for testing and calculating ice adhesion strength using sensors, but also provides a method for further confirming the ice adhesion strength value based on the area of ​​residual ice on the stranded wire surface. Therefore, the method for testing the ice adhesion strength of stranded wires provided by this invention has high reliability, overcoming the problem that the results of testing the ice adhesion strength of stranded wires solely through instruments are not entirely accurate.

[0028] Based on the method provided by this invention, different icing conditions can be simulated in the laboratory, and then stranded wires suitable for use under these conditions can be selected for practical outdoor applications based on the results. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0030] Figure 1 This is a schematic diagram of the mold structure for placing stranded wires in one embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the freezing box for freezing strands in one embodiment of the present invention; Figure 3 This is a schematic diagram of the overall equipment for testing the ice adhesion strength of stranded wire in one embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a clamp for fixing stranded wires in one embodiment of the present invention; Figure 5 This is a schematic diagram of a strand ice adhesion strength test in one embodiment of the present invention; Figure 6 This is a physical image of the equipment used for testing the ice adhesion strength of stranded wire according to the present invention; Figure 7 This is a flowchart of the method for testing the ice adhesion strength of stranded wire according to the present invention; Figure 8 This is a schematic diagram of the water level of a multilayer stranded wire tested in one embodiment of the present invention; Figure 9 This is a physical diagram of the residual ice area of ​​Level I (a) and Level II (b) in one embodiment of the present invention; Figure 10 This is a photograph of residual ice marks on the SLIPS wire 2 in one embodiment of the present invention; Figure 11 This is a photograph of residual ice marks on the SHP conductor 2 in one embodiment of the present invention; Figure 12 This is a schematic diagram of the testing process for a strand with low ice adhesion strength but a large amount of ice residue in one embodiment of the present invention (a is a schematic diagram of the surface of the super-lubricated strand; b is water droplets piercing the super-lubricated oil layer; c is water contacting the rough structure inside the oil and starting to freeze and form an interlock; d is a complete ice layer forming on the outside of the oil layer and locally connecting with the ice inside the oil layer; e is the ice pushing process; f is some ice residue remaining on the surface of the strand after the ice pushing is completed). Figure 13 This is the result of testing the ice adhesion strength of each strand outdoors in one embodiment of the present invention; Figure 14 This is a photograph of a test piece taken outdoors to measure the ice adhesion strength of each strand in one embodiment of the present invention.

[0031] Summary of attached labeling and identification: Wire placement mold-10, marking-11, freezing box-20, insertion hole-21, inlet-outlet-22, first inlet-outlet-22a, second inlet-outlet-22b, thrust sensor-30, metal push rod-31, experimental platform-40, flat plate-41, lifting platform-42, clamp-50, clamp fixing component-51, clamp support component-52, bolt inlet-53. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] In this document, "and / or" includes any and all combinations of one or more of the listed related items.

[0034] In this article, "multiple" means two or more, that is, it includes two, three, four, five, etc.

[0035] As used in this specification, the term "about" typically means + / -5% of the value, more typically + / -4% of the value, more typically + / -3% of the value, more typically + / -2% of the value, even more typically + / -1% of the value, and even more typically + / -0.5% of the value.

[0036] In this specification, certain embodiments may be disclosed in a range-bound format. It should be understood that this "range-bound" description is merely for convenience and brevity and should not be construed as a rigid limitation on the disclosed range. Therefore, the description of a range should be considered as having specifically disclosed all possible subranges and the individual numerical values ​​within those ranges. For example, a description of the range 1-6 should be considered as having specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and the individual numbers within those ranges, such as 1, 2, 3, 4, 5, and 6. This rule applies regardless of the breadth of the range.

[0037] The main experimental materials and equipment involved in this invention are as follows: Aluminum plate (manufacturer), aluminum wire model: JL / LB20A-240 / 30; Other equipment: temperature controller, cooling circulation device, electronically controlled tensile testing machine, humidity controller, humidifier, wire clamps, test molds, and lifting platform.

[0038] Example 1 This embodiment provides an example of a device for testing the ice adhesion strength of aluminum conductors (multilayer aluminum stranded wires).

[0039] Figure 1 A stranded wire placement mold 10 for placing aluminum stranded wire is shown. The mold is a cubic structure with a wall thickness of 5mm, and a semi-circular groove is provided on the surface for placing the aluminum stranded wire to be tested. The size of the semi-circular groove is set to better fix the aluminum stranded wire and prevent it from slipping. The stranded wire placement mold 10 is provided with a mark 11 for marking the ice-free interface.

[0040] Figure 2A double-layered freezing chamber 20 is shown, which has an insertion hole 21 for inserting the metal push rod 31 of the thrust sensor 30 during testing; when not testing, the insertion hole 21 is plugged. The freezing chamber 20 also has multiple inlets and outlets 22 with different heights, allowing for the introduction of refrigerant or air cooling. In some embodiments, the refrigerant enters from the lower first inlet / outlet 22a and exits from the higher first inlet / outlet 22b. The freezing chamber 20 is powered and cooled by an external power unit. In some embodiments, the external power unit can be an external pump for circulating the refrigerant in the freezing chamber 20.

[0041] Figure 3 A schematic diagram of the entire apparatus for testing the ice adhesion strength of aluminum stranded wire is shown. The diagram shows the entire testing apparatus, including a freezing chamber 20, a thrust sensor 30, an experimental platform 40, and a wire clamp 50. The thrust sensor 30 includes a metal push rod 31. During testing, the plug on the insertion hole 21 is opened, and the metal push rod 31 is inserted through the insertion hole 21. The inserted metal push rod 31 enters the ice-solidified interface of the stranded wire through the mark 11 on the mold 10; the mark 11 is located less than or equal to 5 mm below the frozen stranded wire. The experimental platform 40 consists of a thickened flat plate 41 with movable double tracks and a lifting platform 42. The stranded wire placement mold 10 is placed on the lifting platform 42, and the height of the lifting platform 42 is adjusted to ensure good contact between the stranded wire placement mold 10 and the aluminum stranded wire to be tested. Furthermore, both ends of the aluminum stranded wire to be tested are fixed with clamps 50.

[0042] Figure 4 The structure of the clamp 50 for fixing the aluminum stranded wire to be tested is shown. The clamp fixing member 51 of the clamp 50 is a disc-like structure with a thickness of approximately 1 to 1.5 cm; it has a circular hole in the center for fixing the aluminum stranded wire, and the diameter (inner diameter) of the circular hole is set to be 1 cm larger than the diameter of the test stranded wire; the clamp fixing member 51 is also provided with multiple bolt inlets 53 for inserting bolts to tighten the aluminum stranded wire. In addition, the clamp 50 is provided with a clamp support member 52 fixed on the track of the plate 41. The overall height of the clamp 50 corresponds to the hole on the right side of the freezing box 20, thus allowing the thrust sensor 30 to be accurately pushed onto the mold 0.5 to 1 mm below the ice-solid interface.

[0043] The process for testing the ice adhesion strength of aluminum stranded wire using the aforementioned equipment is as follows: The stranded wire to be tested is fixed using two clamps 50. Then, the height of the lifting platform 42 is adjusted, and the stranded wire placement mold 10, filled with distilled water, is placed on it to ensure close contact with the fixed stranded wire. The test environment and time are set for freezing. After freezing, the plug on the side of the freezing chamber 20 is opened, and the metal push rod 31 of the thrust sensor 30 is pushed into the chamber through the insertion hole 21 and stopped just before contacting the mold 10. The position of the push rod is adjusted to ensure that the tip of the metal push rod 31 is below the ice-freezing interface. The push rod speed is set to 0.05~0.5 mm / s along a direction parallel to the longitudinal direction of the aluminum stranded wire to begin the test. The stroke-thrust curve and the maximum thrust value are recorded, and the maximum ice adhesion strength is calculated. A simplified schematic diagram based on the equipment test is shown below. Figure 5 ; Figure 6 This is a physical image of the device used for testing the ice adhesion strength of aluminum stranded wire according to the present invention.

[0044] Example 2 This embodiment provides a specific example of testing the ice adhesion strength of aluminum stranded wire.

[0045] The multilayer aluminum stranded wire used in this embodiment is JL / LB20A-240 / 30.

[0046] Test environment settings: (1) Temperature -10℃~-5℃, humidity not less than 80%RH (for simulating rime ice).

[0047] (2) Temperature below -10℃ and humidity below 50%RH (for simulating frost).

[0048] Freezing time: 30 minutes to 3 hours from the initial temperature to the set temperature.

[0049] In this embodiment, the strand placement mold for placing the aluminum strand to be tested has the following dimensions: length (x), width (y), and height (z): x = 4~6 cm, y = 3~10 cm, z = 1~2 cm. The surface of the mold has a semi-circular groove with a radius of 1.34 cm, and the angle between the two vertices of the semi-circular groove and the center of the aluminum strand to be tested is 120°.

[0050] It is understood that the size of the semi-circular groove in this embodiment is only suitable for JL / LB20A-240 / 30 wires or wires with the same outer diameter. When used for measuring other sizes of stranded wires, molds with different radii can be customized.

[0051] The flowchart of the method for testing the ice adhesion strength of aluminum stranded wire in this embodiment is shown below. Figure 7 .

[0052] Test method: S01: Pre-process the stranded wire to be tested by cutting it into test samples of 30-40 cm in length, then mounting them on the test platform and securing both ends with clamps. Place the test mold on the lifting platform and adjust the lifting platform until the mold and stranded wire are in close contact.

[0053] S02: Add the test liquid (usually distilled water) to the mold. A diagram showing the water addition amount is provided. Figure 8 As shown. Strict control of water addition is required during use. The minimum water level is H2, and the maximum water level should not exceed H1. H2 is the liquid level height sufficient to wet the outermost aluminum wire of the stranded wire; H1 is the liquid level height above the outermost aluminum wire. In some specific implementation scenarios, such as testing blanks and surface-treated JL / LB20A-240 / 30 aluminum-clad steel-core stranded wire, H1 is approximately 6 mm, and the water volume in the mold is approximately 12 mL.

[0054] S03: Freeze according to the set temperature, humidity, and time. After freezing is complete, open the side plug of the freezing chamber, push the metal push rod of the thrust sensor into the chamber through the insertion hole and stop when it is about to contact the mold. Adjust the position of the push rod to ensure that the rod head is ≤5 mm below the ice-solid interface when the metal push rod is inserted into the ice mold. Start the test by setting the push rod speed to 0.05~0.5 mm / s along a direction parallel to the longitudinal direction of the aluminum stranded wire. Record the stroke-thrust curve and the maximum thrust value, and calculate the maximum ice adhesion strength.

[0055] Data processing and results: Ice adhesion strength σ, in kPa.

[0056] (1) σ = 1000 F / A; F: Destructive force, measured in Newtons (N); A: Ice mark area, in square millimeters (mm) 2 ).

[0057] The area of ​​ice marks is calculated based on the ice marks remaining inside the mold, using the following formula: (2) A=a(1-(2arccos(d / D)) / 360°)xy.

[0058] a: Number of aluminum monofilaments in the outermost layer; D: Overall diameter of the conductor; d: Diameter of aluminum monofilament; x, y: the length and width of the ice mark area, respectively.

[0059] Taking JL / LB 20A 240 / 30 stranded wire as an example. JL / LB 20A 240 / 30 aluminum-clad steel core stranded wire is made by precisely stranding 24 pure aluminum monofilaments with a diameter of 3.60mm and 7 aluminum-clad steel core monofilaments with a diameter of 2.40mm. Its structural feature is that the outermost layer consists of 15 pure aluminum monofilaments tightly wound around it. The overall diameter of this stranded wire is approximately 21.6mm. Furthermore, after ice removal, the mold is separated from the stranded wire, and ImageJ image recognition software is used to further evaluate the residual ice area on the multi-layered stranded wire to determine the reliability of the tested ice adhesion strength (whether it can be adopted).

[0060] Residual ice area rating: assessed according to the following rules.

[0061] Level I – Residual ice area less than 10% (±1%): The adhesion between the strand and the ice is almost completely destroyed, with only a small amount of ice residue remaining on the outermost strand surface.

[0062] In this case, it is indicated that the ice adhesion strength of the test strand is low, and natural de-icing can occur under natural conditions.

[0063] Level II – Residual ice area accounts for 10%~80% (±1%): The adhesion between the strand and the ice is partially damaged, but the outermost visible part of the strand is obviously covered with ice.

[0064] In this case, it indicates that the ice adhesion strength of the test strand is moderate, and further de-icing using other methods and equipment is required.

[0065] Level III – Residual ice area exceeds 80% (±1%): The ice layer between the strand and the mold is broken, but the equipment does not accurately measure the adhesion between the strand and the ice.

[0066] In this case, it indicates that the ice adhesion strength of the tested stranded wire is relatively large, and ice has formed between the outer strands and the inner strands of the multi-layer stranded wire. The measured ice adhesion strength only represents the breakdown of the ice-ice cohesion at multiple locations. Therefore, the surface ice-pushing method is not applicable to this type of wire.

[0067] The percentage of residual ice area was calculated using the image recognition software ImageJ.

[0068] When the residual ice area grades obtained from testing the same type of conductor are inconsistent, the sample preparation and measurement process should be repeated, and the final result should be determined when at least three parallel sample measurement results are consistent.

[0069] Table 1-1 Example of judging ice adhesion strength and residual ice area (1) Table 1-2 Example of judging ice adhesion strength and residual ice area (2) Table 1-3 Examples of judging ice adhesion strength and residual ice area (3) Table 1-4 Examples of judging ice adhesion strength and residual ice area (4) Example 3 Based on the method in Example 2, the ice adhesion strength of several different types of stranded wires was tested.

[0070] In this embodiment, the blank conductor is JL / LB20A-240 / 30; in addition, SLIPS conductors and SHP conductors modified from the blank conductors were also used. SLIPS conductors represent aluminum conductors with a super-lubricating coating, prepared according to conventional techniques in the art. SHP conductors represent aluminum conductors with a superhydrophobic coating, prepared according to conventional techniques in the art.

[0071] The test results of ice adhesion strength (ice adhesion strength + residual ice area level) for several different conductors are shown in Table 2.

[0072] Table 2. Test results of ice adhesion strength of aluminum conductors The surface preparation methods for superhydrophobic wires include: 1. Spraying the surface of aluminum stranded wires with commercially available hydrophobic coatings (according to the spraying process recommended in the product instructions); 2. Constructing a micron-level rough structure on the surface of aluminum stranded wires using chemical etching, laser etching, or plasma etching, and then modifying it with low surface energy compounds to achieve superhydrophobicity; 3. Using anodizing, placing the aluminum stranded wires as anodes in an electrolyte (such as phosphoric acid, oxalic acid, etc.) to be oxidized, forming a dense oxide film on the surface of the aluminum stranded wires, and then modifying it with a modifier to obtain a superhydrophobic effect; 4. Preparing a superhydrophobic film by alternating deposition of polyelectrolytes using a layer-by-layer self-assembly method followed by modification with a hydrophobic agent.

[0073] Surface preparation of super-lubricating wires: A porous structure is constructed on the surface of the wire using anodizing. After modification with a modifier, a lubricant is injected into the porous structure to form a lubricating film layer on the surface.

[0074] In Table 2 above, SLIPS wire 1 is an aluminum wire with a super-lubricating coating prepared by a single anodizing process followed by lubricant infusion; SLIPS wire 2 is an aluminum wire with a super-lubricating coating prepared by a double anodizing process followed by lubricant infusion. SHP wire 1 is an aluminum wire with a super-hydrophobic coating prepared by spraying a commercially available superhydrophobic and anti-icing coating. SHP wire 2 is an aluminum wire with a super-hydrophobic coating prepared by anodizing followed by a low surface energy modification method.

[0075] The physical testing results of this embodiment are shown below. Figures 9-11 Among them, 9(a) shows that the adhesion between SLIPS conductor 1 and the mold is completely destroyed, and the residual ice area level is I; 9(b) shows that the ice layer between the blank stranded wire and the mold is broken, and the residual ice area level is III.

[0076] See the actual image of residual ice marks on SLIPS wire 2. Figure 10 Image J calculations show that the residual ice area is approximately 26%, classifying it as Level II. A photograph of the residual ice marks on SHP conductor 2 is available. Figure 11 According to Image J calculations, the residual ice area is approximately 17%, and the residual ice area level is Class II.

[0077] Comparative example: While superhydrophobic or superlubricated stranded wires prepared using conventional methods or commercially available coatings theoretically possess anti-icing properties, there are exceptions. For example, with superlubricated stranded wires, see... Figure 12 Under certain extreme climatic conditions, the following situation may occur: some water penetrates the surface oil layer (yellow part), comes into contact with the rough structure inside the oil and begins to freeze to form an interlock, and then the water continues to freeze outside the oil layer; after freezing, a complete ice layer is formed outside the oil layer and there is a local connection with the ice inside the oil layer. During the ice pushing process, although the maximum pushing force is relatively small, after the ice pushing is completed, it is easy to have (1) a local missing area of ​​ice marks on the mold, and (2) some ice slag remains on the surface of the strand, and this part of the ice slag is located inside the oil layer and is in direct contact with the strand ( Figure 12 f). In this case, although the measured ice adhesion strength value is small, the ice actually breaks during the ice-pushing process, resulting in a large amount of ice remaining on the strand. The above results indicate that the ice adhesion strength value measured by the equipment alone cannot fully guarantee the accuracy of the test results; it is necessary to combine this with the area of ​​ice remaining on the strand for auxiliary confirmation. Experiments have shown that although SLIPS and SHP conductors prepared using conventional methods in the art can be tested for ice adhesion strength using the method of this invention, and most test results are highly reliable, caution is still needed under extreme climatic conditions.

[0078] Based on the results of this embodiment, the implications for practical applications are as follows: different icing conditions can be simulated in the laboratory, and the method of testing ice adhesion strength of this invention can be used to screen stranded wires suitable for use under these conditions. Furthermore, it can guide the practical application of super-lubricating technology in preventing icing of aluminum stranded wires, particularly in the preparation of a rough surface before oil injection. Experiments revealed that if the surface preparation is improper, some water can easily penetrate the oil layer and contact the internal rough structure, freezing and interlocking. After freezing, the ice inside and outside the oil layer connects, resulting in a small pushing force during ice removal, but a missing area of ​​ice marks on the mold afterward. Ice residue remains on the stranded wire surface within the oil layer and directly contacts the stranded wire. Although the ice adhesion strength is low, significant residual ice marks occur due to ice breakage during the ice removal process. To avoid this problem, the surface pretreatment process of the aluminum stranded wire should be optimized, and the surface roughness should be precisely controlled within a suitable range to ensure uniform coverage of the super-lubricating coating, reducing direct contact between ice and the stranded wire and ice residue, thereby improving the anti-icing effect and reliability.

[0079] Example 4 This embodiment provides a method for testing the ice adhesion strength of stranded wire using the method of this invention in a real outdoor environment. (See...) Figure 13 and Figure 14 .

[0080] Among them, coated wires are superhydrophobic wires prepared using commercially available coatings; phosphoric acid wires are superhydrophobic wires prepared using phosphoric acid as an electrolyte; and oxalic acid wires are superhydrophobic wires prepared using oxalic acid as an electrolyte. Figure 13 The blank conductor initially exhibited an ice adhesion strength exceeding 100 kPa, indicating a lack of anti-icing capability. The anti-icing capabilities of the remaining test conductors were ranked as follows: oxalic acid conductor > phosphoric acid conductor > coated conductor.

[0081] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0082] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for testing the ice adhesion strength of multilayer stranded wire, characterized in that, The method includes testing the ice adhesion strength on the surface of a multilayer stranded wire and evaluating the ice adhesion strength test results based on the residual ice area on the surface of the multilayer stranded wire; the multilayer stranded wire includes ordinary multilayer stranded wire, multilayer stranded wire with a superhydrophobic surface, or multilayer stranded wire with a superlubricating surface; The multilayer stranded wire ice adhesion strength test is conducted based on an ice adhesion strength test device, which includes a stranded wire placement mold (10), a freezing box (20), a thrust sensor (30), and an experimental platform (40). The strand placement mold (10) is a cubic structure with a semi-circular groove on its surface for placing the strand to be tested. The size of the semi-circular groove is designed to be slightly larger than the diameter of the strand to be tested so that it is not easy to slide. The experimental platform (40) includes a flat plate (41) with movable double rails and a lifting platform (42). The strand placement mold (10) is placed on the lifting platform (42). The freezing box (20) is placed on the flat plate (41) of the experimental platform (40) for freezing the stranded wire to be tested; an insertion hole (21) is provided on the side of the freezing box (20) for the metal push rod (31) of the thrust sensor (30) to be inserted during the test. During testing: S01: Fix the multi-layer stranded wire to be tested on the flat plate (41); place the stranded wire placement mold (10) on the lifting platform (42), and adjust the height of the lifting platform (42) so that the stranded wire placement mold (10) is in close contact with the multi-layer stranded wire to be tested; S02: Add liquid to the stranded wire placement mold (10) and control the highest liquid level H1 and the lowest liquid level H2; H1 is the liquid level height that covers the outermost strand of the multi-layer stranded wire to be tested; H2 is the liquid level height that can wet the outermost strand of the multi-layer stranded wire to be tested. S03: Set the freezing chamber (20) according to the predetermined temperature, humidity and time to freeze the multilayer stranded wire to be tested and the stranded wire placement mold (10). After freezing, insert the metal push rod (31) of the thrust sensor (30) into the insertion hole (21) and adjust the position so that when the metal push rod (31) is inserted into the freezing mold, the rod head is less than or equal to 5 mm below the ice solidification interface. S04: Move the metal push rod (31) along a direction parallel to the longitudinal direction of the multi-layer stranded wire to be tested, set the push rod speed to 0.05~0.5 mm / s to start the test, and when the stranded wire placement mold (10) is completely detached from the multi-layer stranded wire to be tested, read the maximum value F of the thrust sensor (30); calculate the area of ​​residual ice marks on the stranded wire placement mold (10) to obtain the ice adhesion strength σ of the multi-layer stranded wire to be tested; σ = 1000 F / A; Where A represents the area of ​​the remaining ice mark; A=a(1-(2arccos(d / D)) / 360°)xy; Where a represents the number of outermost single filaments, D represents the overall diameter of the stranded wire, d represents the diameter of a single filament in the stranded wire, and x and y represent the length and width of the ice mark area in the mold. S05: Calculate the residual ice mark area on the multilayer stranded wire to be tested, and set the residual ice mark area to level I, level II or level III; evaluate the ice adhesion strength σ value based on the residual ice mark area level; Residual ice area Level I indicates that the residual ice area on the strand is less than 10%; Residual ice area Level II indicates that the residual ice area on the strand is 10% to 80%; Residual ice area Level III indicates that the residual ice area on the strand exceeds 80%. When the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is classified as Level I, and the ice adhesion strength result obtained from S04 is deemed acceptable. When the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is grade II or III, and the ice adhesion strength result obtained by S04 is not accepted. When the ice adhesion strength σ is 21~100kPa, the residual ice mark area is Grade I, and the ice adhesion strength result obtained by S04 can be adopted. When the ice adhesion strength σ is 21~100kPa, the residual ice mark area is grade II or III, and the ice adhesion strength result obtained by S04 is not accepted. When the ice adhesion strength σ is 10~20kPa, and the residual ice mark area is Grade I, Grade II or Grade III, the ice adhesion strength result obtained by S04 can be adopted. When the ice adhesion strength σ is less than 10 kPa, the residual ice mark area is classified as Grade I or Grade II, and the ice adhesion strength result obtained from S04 is deemed acceptable.

2. The method as described in claim 1, characterized in that, The freezing box (20) is also provided with multiple entrances (22) with height differences.

3. The method as described in claim 1, characterized in that, The multi-layer stranded wire to be tested is fixed on the plate (41) by a clamp (50); the clamp fixing part (51) of the clamp (50) is a disc-like structure with a round hole in the middle for fixing the multi-layer stranded wire to be tested; the clamp fixing part (51) is also provided with multiple bolt inlets (53) for inserting bolts for fastening; the clamp (50) is fixed on the track of the plate (41) by a clamp support part (52).

4. The method as described in claim 3, characterized in that, The height of the circular hole on the clamp fixing member (51) is set to be basically the same as the height of the insertion hole (21) on the freezing box (20).

5. The method as described in claim 1, characterized in that, When used to simulate frost, the temperature of the freezing chamber (20) is set to -10℃ ~ -5℃ and the humidity is not less than 80%RH; or, when used to simulate frost, the temperature of the freezing chamber (20) is set to less than -10℃ and the humidity is less than 50%RH.

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