Equipment and method for testing ice adhesion strength of multi-layer stranded wire and application

Abstract

The invention belongs to the technical field of icing prevention, and particularly relates to equipment and a method for testing the ice adhesion strength of a multi-layer stranded wire and application. The invention firstly provides the equipment for testing the ice adhesion strength of the multi-layer stranded wire with a complex structure, the design of the equipment fully considers the complex structural characteristics of the multi-layer stranded wire, different icing environment conditions can be simulated to freeze the stranded wire to be tested, and the industry vacancy is filled. Secondly, the invention provides a method for testing the ice adhesion strength of the stranded wire based on the equipment for testing the ice adhesion strength, and the method not only provides a method for testing and calculating the 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 credibility is high, and the problem that the result is not completely accurate when the ice adhesion strength of the stranded wire is tested only through an instrument is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of anti-icing, and particularly relates to a device and method for testing ice adhesion strength of a multi-layered strand and application thereof. BACKGROUND

[0002] Component icing, also known as icing, refers to a natural phenomenon that water freezes on the surface of a component. Component icing is a natural disaster phenomenon, such as aircraft icing in the aviation field, cable icing in the energy and power field, and wind turbine set icing, etc. In the energy and power field, icing of a power transmission line causes the gravity of an ice layer and wind load to be superimposed, and if the ice adhesion strength exceeds the bearing limit of the conductor (usually greater than 500 kPa), accidents such as wire breakage and tower collapse will occur. There are three common forms of component icing, namely, precipitation icing, cloud icing and sublimation icing. Among them, precipitation icing is usually formed by freezing rain and water accumulation, and the formed icing structure is compact and harmful. The planned new power system construction in China will inevitably pass through (super) high altitude and heavy icing areas, and the adhesion between icing and matter is an important indicator for evaluating the effect of anti-icing measures. Therefore, it is of great significance to accurately and efficiently test the ice adhesion strength of the equipment icing.

[0003] The mainstream method for testing ice adhesion strength currently adopted includes a shearing method or a centrifugal method. In the ice adhesion strength test using the shearing method, water is injected into a freezing area of a test device in contact with a base material, and then static ice freezing is performed. The adhesion test is completed by separating the icing from the base material through a traction platform or applying a load parallel to the base material. In the ice adhesion strength test using the centrifugal method, the ice rotates in the axial direction of the test device at a constant acceleration, and the ice falls off from the surface of the base material due to the centrifugal force being greater than the adhesion between the ice and the base material, and the adhesion force attached to the workpiece is calculated from the rotation speed. The document "Ice Adhesion Test and Influence Factor Analysis" discloses a method for measuring the adhesion between the ice layer and the base material by a direct shearing method. The document is mainly directed to testing the ice adhesion of flat plate structures made of aluminum, iron, copper and stainless steel, and does not give any inspiration to the testing method of materials with non-flat structures. In addition, the testing method for the ice adhesion strength of materials such as aluminum plates with flat structures in the field is relatively perfect, but there are few related reports on the ice adhesion strength of multi-layered strands with complex structures. The mainstream method of directly measuring the adhesion between the ice layer and the base material cannot accurately guide the ice adhesion strength of the multi-layered strand, because the icing interlocking phenomenon often occurs in the actual use of the multi-layered strand, and the existing ice adhesion strength test method can only detect the surface icing.

[0004] In addition, the existing test technology also has the problem of mismatching between the accuracy of test results and the scene adaptability, that is, many existing test data are based on an ideal model condition and deviate from the actual application scene. For example, it is embodied in: (1) poor data reliability: the calculated icing area deviates from the estimated icing area, and the ice thickness cannot be accurately quantified (such as CN 102628789 A); the use of manual ice pushing and the non-specification of the ice pushing rate of the automatic device will lead to inaccurate and poor reproducible final results (such as CN 102269691 A). (2) rough icing control: different contact angles of the same volume of water droplets and the contact area of the test surface are completely different (especially for super-hydrophobic materials), which finally leads to uncontrollable size and morphology of icing (such as CN 102269691 A). (3) mechanical loading interference: the traditional centrifugal peeling method causes internal crack propagation of the ice layer due to high-speed rotation, and the measured value deviates from the true interfacial bonding strength; the immersion pull-out method inevitably forms a connection between the ice and the ice due to the space left in the aluminum wire, and there is a large amount of ice-ice bonding force in addition to the ice-solid adhesion force when measuring the maximum pulling force (such as CN 114878457 A). (4) ambiguous parameter definition: the international standard (such as SAE ARP 5485) does not clearly define the physical boundary of "ice adhesion strength" (such as interfacial failure criterion and ice layer cohesion failure compensation method).

[0005] In summary, in order to accurately test the ice adhesion strength of the multi-layer wire and correctly evaluate the anti-icing performance of the multi-layer wire, a new method strategy is urgently needed to fill the gap in the industry. SUMMARY

[0006] The purpose of the present application is to provide an equipment and an evaluation method for wire ice adhesion strength test, which partially solves or alleviates the above-mentioned deficiencies in the prior art. The present application specifically adopts the following technical solutions.

[0007] In one aspect, the present application provides a method for testing the ice adhesion strength of a multi-layer wire.

[0008] A method for evaluating the ice adhesion strength of a multi-layer wire, the method comprising (directly) testing the ice adhesion strength of a multi-layer wire surface and evaluating the ice adhesion strength test result based on the residual ice area on the multi-layer wire surface (evaluating the reliability of the directly tested ice adhesion strength); The ice adhesion strength test of the multi-layer wire is based on an ice adhesion strength test equipment, and the ice adhesion strength test equipment comprises a wire placement mold (10), a freezing box (20), a thrust sensor (30) and an experimental platform (40); The stranded wire placement mold (10) is a whole cubic structure, and a semicircular groove is arranged on the surface for placing the stranded wire to be tested, the size of the semicircular groove is slightly larger than the diameter of the stranded wire to be tested so that the stranded wire to be tested is not easy to slide; the experimental platform (40) comprises a 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); The freezing box (20) is placed on the flat plate (41) of the experimental platform (40) for freezing the stranded wire to be tested; a insertion hole (21) is arranged on the side of the freezing box (20) for inserting the metal push rod (31) of the push force sensor (30) during testing; During testing: S01: fixing the multi-layer stranded wire to be tested on the flat plate (41); placing the stranded wire placement mold (10) on the lifting platform (42), and adjusting the height of the lifting platform (42) to make the stranded wire placement mold (10) closely fit the multi-layer stranded wire to be tested; S02: adding liquid into the stranded wire placement mold (10), and controlling the highest liquid adding level H1 and the lowest liquid adding level H2; the H1 is the liquid level height that does not cover the outermost layer of the multi-layer stranded wire to be tested; the H2 is the liquid level height that can wet the outermost layer of the multi-layer stranded wire to be tested; S03: setting the freezing box (20) according to the predetermined temperature, humidity and time to freeze the multi-layer stranded wire to be tested and the stranded wire placement mold (10), and after the freezing is completed, the metal push rod (31) of the push force sensor (30) is inserted from the insertion hole (21), and the position is adjusted so that the rod head is below the ice solidification interface at a position less than or equal to 5 mm when the metal push rod (31) is inserted into the ice mold; S04: making the metal push rod (31) move along the direction parallel to the longitudinal direction of the multi-layer stranded wire to be tested, setting the push rod speed to 0.05-0.5 mm / s to start testing, and when the stranded wire placement mold (10) completely separates from the multi-layer stranded wire to be tested, the maximum value F of the push force sensor (30) is read out; the residual ice mark area on the stranded wire placement mold (10) is calculated to obtain the ice adhesion strength σ of the multi-layer stranded wire to be tested; σ=F / A; Wherein, A represents the residual ice mark area; A=a(1-(2arccos(d / D)) / 360)xy; Wherein, a represents the number of outermost single wires, D represents the overall diameter of the stranded wire, d represents the diameter of the stranded wire single wire, and x and y represent the length and width of the mold ice mark area; S05: (using an image processing program) calculating the residual ice mark area on the multi-layer stranded wire to be tested, setting the residual ice mark area as level I, level II or level III; and evaluating the ice adhesion strength σ value based on the residual ice mark area level (specifically, evaluating whether the ice adhesion strength σ can be adopted based on the residual ice mark area level).

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

[0010] Further, the residual ice mark area level I represents that the residual ice area on the stranded wire is less than 10%; the residual ice mark area level II represents that the residual ice area on the stranded wire accounts for 10% to 80%; and the residual ice mark area level III represents that the residual ice area on the stranded wire is more than 80%.

[0011] Further, when the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is level I, and it is determined that the ice adhesion strength result can be adopted; when the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is level II or III, and it is determined that the ice adhesion strength result is not adopted; when the ice adhesion strength σ is 21 to 100 kPa, the residual ice mark area is level I, and it is determined that the ice adhesion strength result can be adopted; when the ice adhesion strength σ is 21 to 100 kPa, the residual ice mark area is level II or III, and it is determined that the ice adhesion strength result is not adopted; when the ice adhesion strength σ is 10 to 20 kPa, the residual ice mark area is level I, level II or level III, and it is determined that the ice adhesion strength result can be adopted; when the ice adhesion strength σ is less than 10 kPa, the residual ice mark area is level I, level II or level III, and it is determined that the ice adhesion strength result can be adopted.

[0012] Further, the freezing box (20) is further provided with a plurality of entrances and exits (22) with height differences.

[0013] Further, the multi-layer stranded wire to be tested is fixed on the flat plate (41) through the clamp (50); the clamp fixing part (51) of the clamp (50) is a disc structure as a whole, and a circular hole is arranged in the middle for fixing the multi-layer stranded wire to be tested; a plurality of bolt entrances (53) are further arranged on the clamp fixing part (51) for inserting bolts for fastening; and the clamp (50) is fixed on the track of the flat plate (41) through the clamp support part (52).

[0014] Further, the height of the circular hole on the clamp fixing part (51) is basically consistent with the height of the insertion hole (21) on the freezing box (20).

[0015] Further, when used for simulating glaze ice, the temperature of the freezing box (20) is set to -10℃ ~ -5℃, and the humidity is not less than 80%RH; or, when used for simulating rime, the temperature of the freezing box (20) is set to less than -10℃, and the humidity is less than 50%RH.

[0016] Another aspect of the present application is to provide a device for testing ice adhesion strength of multi-layered stranded wire.

[0017] A device for testing ice adhesion strength of multi-layered stranded wire, the device comprising a stranded wire placement mold (10), a freezing box (20), a thrust sensor (30) and an experimental platform (40); The stranded wire placement mold (10) is in a cubic structure as a whole, and a semicircular groove is arranged on the surface for placing the wire to be tested, the size of the semicircular groove being designed to be slightly larger than the diameter of the stranded wire to be tested so that it is not easy to slide; The experimental platform (40) comprises a flat plate (41) with movable double tracks and a lifting platform (42); the lifting platform (42) places the stranded wire placement mold (10) thereon; The freezing box (20) is placed on the flat plate (41) of the experimental platform (40) and is used for freezing the multi-layered stranded wire to be tested; a plug-in hole (21) is arranged on the side of the freezing box (20) for the metal push rod (31) of the thrust sensor (30) to be inserted during testing; The device further comprises a clamp (50) for fixing the multi-layered stranded wire to be tested on the flat plate (41); the clamp fixing member (51) of the clamp (50) is in a disc-like structure as a whole, and a circular hole is arranged in the middle for fixing the multi-layered stranded wire to be tested; a plurality of bolt inlets (53) are further arranged on the clamp fixing member (51) for inserting bolts; the clamp (50) is fixed on the tracks of the flat plate (41) through a clamp support member (52).

[0018] Further, the height of the circular hole on the clamp fixing member (51) is set to be substantially consistent with the height of the plug-in hole (21) on the freezing box (20).

[0019] Further, a power device is connected to the freezing box (20) for circulating the freezing circulating liquid or cold air in the box.

[0020] Another aspect of the present application can also provide specific applications of the above method.

[0021] The multi-layered stranded wire with ice adhesion strength screened by the above method can be used in the preparation of anti-icing wire.

[0022] Specifically, the ice adhesion strength of various multi-layered strands with super-lubricating surface or super-hydrophobic surface is tested according to the simulated outdoor icing conditions in the laboratory, and the multi-layered strands with the ice adhesion strength results that can be adopted are selected for the actual outdoor anti-icing.

[0023] In another aspect, the present application can also provide a method for screening a strand with anti-icing performance in the outdoor.

[0024] A method for screening a strand with anti-icing performance in the outdoor, the method is to screen a strand with ice adhesion strength test results that can be adopted in the laboratory conditions (for actual outdoor use); The ice adhesion strength test is based on an ice adhesion strength test device, which includes a strand placement mold (10), a freezing box (20), a thrust sensor (30) and an experimental platform (40); The strand placement mold (10) is a whole cube structure, and a semicircular groove is arranged on the surface for placing the strand to be tested. The size of the semicircular 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 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) and is used for freezing the strand to be tested. A insertion hole (21) is arranged 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 the test: S01: fixing the multi-layered strand to be tested on the flat plate (41); placing the strand placement mold (10) on the lifting platform (42) and adjusting the height of the lifting platform (42) to make the strand placement mold (10) closely fit the multi-layered strand to be tested; S02: adding liquid to the strand placement mold (10) and controlling the highest liquid level H1 and the lowest liquid level H2; the H1 is the liquid level that does not cover the outermost layer of the multi-layered strand to be tested; the H2 is the liquid level that can wet the outermost layer of the multi-layered strand to be tested; S03: freezing the multi-layered strand to be tested and the strand placement mold (10) according to the predetermined temperature, humidity and time setting of the freezing box (20), and inserting the metal push rod (31) of the thrust sensor (30) from the insertion hole (21) after the freezing is completed, and adjusting the position to make the rod head of the metal push rod (31) be below the ice-solidification interface less than or equal to 5 mm when it is inserted into the ice mold; S04: Start the test with the metal push rod (31) at a speed of 0.05-0.5 mm / s along a direction parallel to the longitudinal direction of the multi-layer stranded wire to be tested, and read the maximum value F of the push force sensor (30) when the stranded wire placement mold (10) is completely separated from the multi-layer stranded wire to be tested; calculate the residual ice mark area on the stranded wire placement mold (10) to obtain the ice adhesion strength σ of the multi-layer stranded wire to be tested; σ=F / A; Wherein, A represents the residual ice mark area; A=a(1-(2arccos(d / D)) / 360)xy; Wherein, a represents the number of outermost filaments, D represents the overall diameter of the stranded wire, d represents the diameter of the stranded wire filament, x and y represent the length and width of the ice mark area of the mold; S05: (using an image processing program) Calculate the residual ice mark area on the multi-layer stranded wire to be tested, and set the residual ice mark area to level I, level II or level III; based on the residual ice mark area level, determine whether the ice adhesion strength σ can be adopted.

[0025] Further, the residual ice mark area level I represents that the residual ice area on the stranded wire is less than 10%; the residual ice mark area level II represents that the residual ice area on the stranded wire accounts for 10%-80%; and the residual ice mark area level III represents that the residual ice area on the stranded wire is more than 80%.

[0026] Further, the evaluation rules are as follows: When the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is level I, and the ice adhesion strength result is determined to be acceptable; When the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is level II or III, and the ice adhesion strength result is determined to be unacceptable; When the ice adhesion strength σ is 21-100 kPa, the residual ice mark area is level I, and the ice adhesion strength result is determined to be acceptable; When the ice adhesion strength σ is 21-100 kPa, the residual ice mark area is level II or III, and the ice adhesion strength result is determined to be unacceptable; When the ice adhesion strength σ is 10-20 kPa, the residual ice mark area is level I, level II or level III, and the ice adhesion strength result is determined to be acceptable; When the ice adhesion strength σ is less than 10 kPa, the residual ice mark area is level I, level II or level III, and the ice adhesion strength result is determined to be acceptable.

[0027] Beneficial technical effects: The present application firstly provides a device for testing ice adhesion strength of a multi-layered stranded wire with complex structure, which is designed in full consideration of the complex structure characteristics of the multi-layered stranded wire and can also 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 a stranded wire based on the device for testing ice adhesion strength. The method combines the structure characteristics of the device, pushes ice on the surface of the stranded wire, reads the reading of the pushed ice, and then calculates the ice adhesion strength on the surface of the stranded wire. However, the method of the present application 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 method for testing ice adhesion strength of a stranded wire provided by the present application has high result reliability and overcomes the problem that the result of testing ice adhesion strength of a stranded wire by using an instrument is not completely accurate.

[0028] Based on the method provided by the present application, different icing conditions can be simulated in a laboratory, and then the stranded wire suitable for the conditions is selected for outdoor practical application according to the results. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. In all the drawings, similar elements or parts are generally identified by similar reference signs. In the drawings, each element or part is not necessarily drawn according to the actual proportion. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0030] Figure 1 The structure diagram of a mold for placing a stranded wire in one of the embodiments of the present application; Figure 2 The structure diagram of a freezing box for freezing a stranded wire in one of the embodiments of the present application; Figure 3 The overall device schematic diagram for testing ice adhesion strength of a stranded wire in one of the embodiments of the present application; Figure 4 The structure diagram of a clamp for fixing a stranded wire in one of the embodiments of the present application; Figure 5 The schematic diagram for testing ice adhesion strength of a stranded wire in one of the embodiments of the present application; Figure 6 The physical diagram of the device for testing ice adhesion strength of a stranded wire of the present application; Figure 7 The flowchart of the method for testing ice adhesion strength of a stranded wire of the present application; Figure 8 A schematic diagram of the water addition height of the multi-layered stranded wire tested in one of the embodiments of the present application; Figure 9 A physical diagram of the residual ice area of Grade I (a) and Grade II (b) in one of the embodiments of the present application; Figure 10 A physical diagram of the residual ice mark of the SLIPS wire 2 in one of the embodiments of the present application; Figure 11 A physical diagram of the residual ice mark of the SHP wire 2 in one of the embodiments of the present application; Figure 12 A schematic diagram of the test process of the stranded wire with low ice adhesion strength but with more residual ice slag in one of the embodiments of the present application (a is a schematic diagram of the surface of the super-lubricated stranded wire; b is a water drop puncturing the super-lubricated oil layer; c is the water body contacting the inner rough structure of the oil layer and starting to freeze to form interlocking; d is the formation of a complete ice layer on the outside of the oil layer and the partial connection with the inner ice body of the oil layer; e is the ice pushing process; f is the stranded wire surface still with some ice slag remaining after the ice pushing is completed); Figure 13 The results of the ice adhesion strength test of each stranded wire in the outdoor environment in one of the embodiments of the present application; Figure 14 A physical diagram of the ice adhesion strength test of each stranded wire in the outdoor environment in one of the embodiments of the present application.

[0031] Summary of the identification of the reference signs: Stranded wire placement mold-10, marker-11, freezing box-20, insertion hole-21, inlet and outlet-22, first inlet and outlet-22a, second inlet and outlet-22b, thrust sensor-30, metal push rod-31, experimental platform-40, flat plate-41, lifting platform-42, clamp-50, clamp fixing member-51, clamp support member-52, bolt inlet-53. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] In this document, “and / or” includes any and all combinations of one or more of the associated items.

[0034] In this document, “a plurality of” means two or more, that is, it includes two, three, four, five, and the like.

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

[0036] In this specification, certain embodiments can be disclosed in one format in terms of a range. It is to be understood that such a "range in terms of" description is used for convenience and brevity and should not be construed as a rigid limitation on the scope of the disclosure. Accordingly, the description of a range should be considered as having specifically disclosed all possible subranges as well as individual numerical values within that range. For example, a description of a range 1-6 should be considered as having specifically disclosed subranges like 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., as well as individual numbers within that range, for example 1, 2, 3, 4, 5, and 6. The above rule applies regardless of the breadth of the range.

[0037] The main experimental materials and equipment involved in the present application are as follows: Aluminum plate (manufacturer), aluminum wire type: JL / LB20A-240 / 30; Other equipment: temperature controller, cooling circulation device, electric control tension test press, humidity controller, humidifying device, wire clamp, test mold, lifting platform.

[0038] Example 1 This example provides an example of a device for testing the ice adhesion strength of aluminum wire (multi-layer aluminum stranded wire).

[0039] Figure 1 A stranded wire placement mold 10 for placing aluminum stranded wire is shown, which is a whole cube structure with a wall thickness of 5 mm, and a semicircular groove is provided on the surface for placing the aluminum stranded wire to be tested. The size of the semicircular groove is set to better fix the aluminum stranded wire so that it is not easy to slide. The stranded wire placement mold 10 is provided with a mark 11 for marking the ice solidification interface.

[0040] Figure 2A double-layer structure of the freezing box 20 is shown, which is provided with an insertion hole 21 for the metal push rod 31 of the push force sensor 30 to be inserted when testing; when not testing, the insertion hole 21 is plugged with a plug. The freezing box 20 is also provided with multiple inlets and outlets 22 with height differences, through which the refrigeration circulating liquid or air cooling can be introduced. In some embodiments, the refrigeration circulating liquid is introduced from the first inlet 22a at a low position and discharged from the first inlet 22b at a high position. The freezing box 20 is connected to a power device, which is powered and cooled. In some embodiments, the external power device can be an external pump for circulating the refrigeration circulating liquid in the freezing box 20.

[0041] Figure 3 The entire device schematic for the ice adhesion strength test of aluminum strands is shown. As can be seen from the figure, the entire test device includes a freezing box 20, a push force sensor 30, an experimental platform 40 and a wire clamp 50. Among them, the metal push rod 31 is also arranged in the push force sensor 30, when testing, the plug on the insertion hole 21 is opened, and the metal push rod 31 is inserted from the insertion hole 21, and the inserted metal push rod 31 enters the ice-solid interface of the strand from the mark 11 of the mold 10; the position of the mark 11 is located below the ice-covered strand less than or equal to 5 mm. The experimental platform 40 is composed of a thickened flat plate 41 with a movable double track and a lifting platform 42. Among them, the lifting platform 42 places the strand placement mold 10, and the height of the lifting platform 42 is adjusted to make the strand placement mold 10 on it better fit the aluminum strand to be tested. In addition, the ends of the aluminum strand to be tested are fixed with the clamp 50.

[0042] Figure 4 The structure of the clamp 50 for fixing the aluminum strand to be tested is shown. The clamp fixing part 51 of the clamp 50 is a disc-like structure as a whole, with a thickness of about 1-1.5 cm; there is a circular hole in the middle for fixing the aluminum strand, and the diameter (inner diameter) of the circular hole is set to be greater than the diameter of the test strand by 1 cm; the clamp fixing part 51 is also provided with multiple bolt inlets 53 for inserting bolts to fasten the aluminum strand. In addition, the clamp 50 is also provided with a clamp support part 52 fixed on the track of the flat plate 41. The overall height of the clamp 50 corresponds to the hole on the right side of the freezing box 20, so that the push force sensor 30 can accurately push onto the mold below the ice-solid interface by 0.5-1 mm.

[0043] The process of testing the ice adhesion strength of aluminum strands based on the above device is as follows: The test wire is fixed using two clamps 50, and then the height of the lifting platform 42 is adjusted to place the wire placement mold 10 filled with distilled water in close contact with the fixed test wire, set the test environment and time for freezing. After freezing, open the plug on the side of the freezing box 20, and push the metal push rod 31 of the push sensor 30 through the insertion hole 21 into the box and stop when it is about to contact the mold 10; adjust the push rod position to ensure that the head of the metal push rod 31 is below the ice-solidification interface, set the push rod speed to 0.05-0.5 mm / s to start the test, record the displacement-pushing force curve and the maximum pushing force value, and calculate the maximum ice adhesion strength. The brief schematic diagram of the equipment test is shown in Figure 5 ; Figure 6 The physical diagram of the device for testing the ice adhesion strength of the aluminum wire of the present application.

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

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

[0046] Test environment setting: (1) Temperature -10℃~-5℃, humidity not less than 80%RH (used to simulate rime ice).

[0047] (2) Temperature below -10℃, humidity below 50%RH (used to simulate hoar frost).

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

[0049] In this embodiment, the wire placement mold for placing the test aluminum wire is set to have a length (x), a width (y), and a height (z) of x = 4~6 cm, y = 3~10 cm, and z = 1~2 cm, respectively. The mold surface is provided with a semicircular groove with a radius of 1.34 cm, and the included angle formed by the two boundary vertices of the semicircular groove and the center of the test aluminum wire is 120°.

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

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

[0052] Test method: S01: Pretreatment of the test wire, cut it into 30~40 cm long test sample, then install it on the test platform, and fix both ends with clamps. Place the test mold on the lifting platform, adjust the lifting platform until the mold is tightly fitted with the wire.

[0053] S02: Add test liquid (usually distilled water) to the mold. The water addition amount is shown in Figure 8 . When in use, the water addition amount must be strictly controlled, the minimum water amount position is H2, and the maximum water amount position is not more than H1. H2 is the liquid level that can wet the outermost layer of aluminum wire; H1 is the liquid level that does not cover the outermost layer of aluminum wire. In some specific implementation cases, such as testing blank and JL / LB20A-240 / 30 aluminum-clad steel core aluminum wire after surface treatment, H1 is about 6 mm, and the water amount added in the mold is about 12 mL.

[0054] S03: Freeze according to the set temperature, humidity and time. After the freezing is completed, open the side plug of the freezing box, push the metal push rod of the push sensor through the insertion hole into the box body and stop when it is about to contact the mold, adjust the push rod position to ensure that the rod head is below the ice-solid interface ≤5 mm when the metal push rod is inserted into the frozen mold, set the push rod speed to 0.05~0.5 mm / s to start the test, record the displacement-pushing force curve and the maximum pushing force value, and calculate the maximum ice adhesion strength.

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

[0056] (1) σ = F / A; F: breaking force, unit: Newton (N); A: ice mark area, unit: square millimeter (mm 2 ).

[0057] The ice mark area is calculated by the residual ice mark in the mold, using the following formula: (2) A = a(1-(2arccos(d / D)) / 360)xy.

[0058] a: the number of outermost aluminum filaments; D: the overall diameter of the wire; d: the diameter of the aluminum filament; x, y: length and width of the ice mark area, respectively.

[0059] Take JL / LB 20A 240 / 30 strand as an example. JL / LB 20A 240 / 30 aluminum-clad steel core aluminum strand is made of 24 pure aluminum filaments with a diameter of 3.60 mm and 7 aluminum-clad steel core filaments with a diameter of 2.40 mm after precise stranding, and its structural feature is that the outermost layer is tightly surrounded by 15 pure aluminum filaments. The overall diameter of the strand is about 21.6 mm. Further, after the ice pushing is completed, the mold is separated from the strand, and the residual ice area on the multi-layer strand is further evaluated using the Image J image recognition software to determine the credibility of the ice adhesion strength test (whether it can be adopted).

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

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

[0062] In this case, it indicates that the ice adhesion strength of the test strand is small, and natural ice shedding can occur in the natural environment.

[0063] Grade II - Residual ice area accounts for 10%~80% (±1%): The adhesion between the strand and the ice is partially destroyed, but the outermost layer of the strand can be seen to be partially covered with ice.

[0064] In this case, it indicates that the ice adhesion strength of the test strand is moderate, and further deicing needs to be carried out using other methods and equipment.

[0065] Grade III - Residual ice area more than 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 test strand is large, and the outer layer of the multi-layer strand and the inner layer of the strand have frozen together. The measured ice adhesion strength only represents the destruction of the ice cohesion at multiple positions, so the surface ice pushing method is not suitable for such conductors.

[0067] The percentage of residual ice area is calculated using the image recognition software Image J.

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

[0069] Table 1-1 Ice adhesion strength and residual ice area judgment example (1) Table 1-2 Ice adhesion strength and residual ice area judgment example (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 The ice adhesion strength of several different types of strands was tested based on the method of Example 2.

[0070] The blank strand in this example was JL / LB20A-240 / 30; in addition, a SLIPS strand and a SHP strand based on modification of the blank strand were also used. The SLIPS strand represents an aluminum strand with a super-lubricating coating, which was prepared according to conventional technical means in the art. The SHP strand represents an aluminum strand with a super-hydrophobic coating, which was prepared according to conventional technical means in the art.

[0071] The results of the ice adhesion strength test of several different strands (ice adhesion strength + residual ice area grade) are shown in Table 2.

[0072] Table 2 Results of the ice adhesion strength test of aluminum strands The surface preparation method of the super-hydrophobic strand includes: 1. Spraying the surface of the aluminum strand with a commonly available commercial hydrophobic coating (according to the recommended spraying process of the product instructions); 2. Constructing a micron-level rough structure on the surface of the aluminum strand by means of chemical etching, laser etching or plasma etching, and then modifying to achieve super-hydrophobicity using a low-surface-energy compound; 3. Placing the aluminum strand as an anode in an electrolyte (such as phosphoric acid, oxalic acid, etc.) to be oxidized by anodic oxidation, so that a dense oxide film is formed on the surface of the aluminum strand, and a modifier is used to modify to obtain super-hydrophobicity; 4. Using the layer-by-layer self-assembly method to deposit polyelectrolytes alternately, and then using a hydrophobic agent to modify to prepare a super-hydrophobic film.

[0073] Surface preparation of super-lubricating strand: using anodic oxidation to construct a porous structure on the surface of the strand, and then using a modifier to modify, and then filling the porous structure with a lubricant and forming a lubricating film layer on the surface.

[0074] In the above Table 2, SLIPS strand 1 is an aluminum strand with a super-lubricating coating prepared by single anodic oxidation plus lubricant filling; SLIPS strand 2 is an aluminum strand with a super-lubricating coating prepared by twice anodic oxidation plus lubricant filling. SHP strand 1 is an aluminum strand with a super-hydrophobic coating prepared by spraying a commercial super-hydrophobic anti-icing coating. SHP strand 2 is an aluminum strand with a super-hydrophobic coating prepared by anodic oxidation plus low-surface-energy modification method.

[0075] The actual detection results of the embodiment are shown in Figures 9-11 , wherein 9(a) is that the adhesion of the SLIPS wire 1 to the mold is completely destroyed, and the residual ice area level is grade I; 9(b) is that the ice layer between the blank wire and the mold is broken, and the residual ice area level is grade III.

[0076] The residual ice mark actual photo of the SLIPS wire 2 is shown in Figure 10 , and the residual ice area is about 26% calculated by Image J, and the residual ice area level is grade II. The residual ice mark actual photo of the SHP wire 2 is shown in Figure 11 , and the residual ice area is about 17% calculated by Image J, and the residual ice area level is grade II.

[0077] Comparative example: Although the super-hydrophobic or super-hydrophobic surface wire prepared by the conventional method or the commercially available coating has the anti-icing effect in theory, there are some exceptions. Taking the super-hydrophobic wire as an example, as shown in Figure 12 , under some extreme climate conditions, the following conditions may occur: part of the water penetrates the surface oil layer (yellow part), contacts the rough structure in the oil, and begins to freeze to form interlocking, and then the water continues to freeze outside the oil layer; after freezing, a complete ice layer is formed outside the oil layer and is locally connected with the ice body inside the oil layer. During the ice pushing process, although the maximum pushing force value is relatively small, after the ice pushing is completed, (1) the ice mark area of the mold is partially missing, and (2) part of the ice residue remains on the surface of the wire, and the part of the ice residue is located inside the oil layer and directly contacts the wire Figure 12 f). In this case, although the measured ice adhesion strength value is small, in fact, the ice body is broken during the ice pushing process, so more ice remains on the wire. The above results show that the ice adhesion strength value measured by the equipment cannot completely guarantee the accuracy of the test results, and the residual ice area on the wire needs to be confirmed. It is found through experiments that although the SLIPS wire and the SHP wire prepared by the conventional method in the art can be tested for ice adhesion strength by the method of the present application, most of the test results have high reliability, but attention should be paid to extreme climate conditions.

[0078] Based on the results of the present embodiment, the inspiration for practical application: can be simulated in the laboratory under different icing conditions, using the method of the present application to test the ice adhesion strength, screen out the twisted wire suitable for use under the condition. In addition, it can also guide the actual use of super lubrication technology in the aluminum twisted wire anti-icing, the preparation of the rough surface before oil injection. It is found through experiments that if the surface preparation is unreasonable, part of the water will pass through the oil layer and contact the internal rough structure and freeze interlocking, after freezing, the ice inside and outside the oil layer is connected with each other, although the pushing force is small, but after the end of the mold ice mark area appears loss, the ice residue is still on the surface of the twisted wire and directly contacts with the twisted wire, although the ice adhesion strength is small, but because of the ice body fracture during the ice pushing process, a larger residual ice mark appears. In order to avoid this problem, the surface pretreatment process of aluminum twisted wire should be optimized, the surface roughness should be accurately controlled in the appropriate range, the super lubrication coating should be uniformly covered, the direct contact between ice and twisted wire and ice residue should be reduced, and the anti-icing effect and reliability should be improved.

[0079] Embodiment 4 The present embodiment provides a twisted wire ice adhesion strength tested by the method of the present application in outdoor real environment, see Figure 13 and Figure 14 .

[0080] Among them, the coating wire is a super-hydrophobic wire prepared by using commercial coating; the phosphoric acid wire is a super-hydrophobic wire prepared by using phosphoric acid as electrolyte; the oxalic acid wire is a super-hydrophobic wire prepared by using oxalic acid as electrolyte. Figure 13 The ice adhesion strength of the blank wire in the initial stage exceeds 100kPa, which indicates that it does not have anti-icing ability. The anti-icing ability of the rest of the test wires is oxalic acid wire > phosphoric acid wire > coating wire.

[0081] It should be noted that in this document, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusions, so that processes, methods, articles or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or include elements inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "including a…" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0082] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative, not limiting, and those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims. These are all within the protection of the present application.

Claims

1. A method for testing ice adhesion strength of a multilayer strand, characterized by, The method comprises testing the ice adhesion strength of the multi-layer strand surface and evaluating the ice adhesion strength test result based on the residual ice area on the multi-layer strand surface; The ice adhesion strength test of the multi-layer strand is based on an ice adhesion strength test device, which comprises a strand placement mold (10), a freezing box (20), a thrust sensor (30) and an experimental platform (40); The strand placement mold (10) is in the form of a cube, and a semicircular groove is arranged on the surface for placing the strand to be tested. The size of the semicircular groove is slightly larger than the diameter of the strand to be tested so that it is not easy to slide; the experimental platform (40) comprises 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) and is used for freezing the strand to be tested; a insertion hole (21) is arranged on the side of the freezing box (20) for inserting the metal push rod (31) of the thrust sensor (30) during the test; During the test: S01: fixing the multi-layer strand to be tested on the flat plate (41); placing the strand placement mold (10) on the lifting platform (42) and adjusting the height of the lifting platform (42) so that the strand placement mold (10) closely contacts the multi-layer strand to be tested; S02: adding liquid to the strand placement mold (10) and controlling the maximum liquid level H1 and the minimum liquid level H2; the H1 is the liquid level above the outermost layer of the multi-layer strand to be tested; the H2 is the liquid level that can wet the outermost layer of the multi-layer strand to be tested; S03: setting the freezing box (20) according to the predetermined temperature, humidity and time to freeze the multi-layer strand to be tested and the strand placement mold (10); after the freezing is completed, the metal push rod (31) of the thrust sensor (30) is inserted from the insertion hole (21) and the position is adjusted so that the rod head is below the ice solidification interface at a position less than or equal to 5 mm when the metal push rod (31) is inserted into the ice mold; S04: making the metal push rod (31) move along the direction parallel to the longitudinal direction of the multi-layer strand to be tested, setting the push rod speed to 0.05-0.5 mm / s to start the test; when the strand placement mold (10) completely separates from the multi-layer strand to be tested, the maximum value F of the thrust sensor (30) is read out; the residual ice mark area on the strand placement mold (10) is calculated to obtain the ice adhesion strength σ of the multi-layer strand to be tested; σ=F / A; wherein A represents the residual ice mark area; A=a(1-(2arccos(d / D)) / 360)xy; wherein a represents the number of outermost single filaments, D represents the overall diameter of the strand, d represents the diameter of the single filament of the strand, and x and y represent the length and width of the ice mark area of the mold. S05: Calculate the residual ice mark area on the measured multi-layer stranded wire, 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.

2. The method of claim 1, wherein, The residual ice mark area level I represents that the residual ice area on the stranded wire is less than 10%; the residual ice mark area level II represents that the residual ice area on the stranded wire accounts for 10%-80%; and the residual ice mark area level III represents that the residual ice area on the stranded wire is more than 80%.

3. The method of claim 1, wherein, when the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is level I, and the ice adhesion strength result is determined to be acceptable; when the ice adhesion strength σ is greater than 100 kPa, the residual ice mark area is level II or III, and the ice adhesion strength result is determined to be unacceptable; when the ice adhesion strength σ is 21-100 kPa, the residual ice mark area is level I, and the ice adhesion strength result is determined to be acceptable; when the ice adhesion strength σ is 21-100 kPa, the residual ice mark area is level II or III, and the ice adhesion strength result is determined to be unacceptable; when the ice adhesion strength σ is 10-20 kPa, the residual ice mark area is level I, II or III, and the ice adhesion strength result is determined to be acceptable; when the ice adhesion strength σ is less than 10 kPa, the residual ice mark area is level I, II or III, and the ice adhesion strength result is determined to be acceptable.

4. The method of claim 1, wherein, The freezing box (20) is further provided with a plurality of entrances (22) with height differences.

5. The method of claim 1, wherein, The measured multi-layer stranded wire is fixed on the flat plate (41) by the clamp (50); the clamp fixing part (51) of the clamp (50) is a disc structure as a whole, and a circular hole is arranged in the middle for fixing the measured multi-layer stranded wire; a plurality of bolt entrances (53) are further arranged on the clamp fixing part (51) for inserting bolts for fastening; the clamp (50) is fixed on the track of the flat plate (41) by the clamp support part (52).

6. The method of claim 5, wherein, The height of the circular hole on the clamp fixing part (51) is basically consistent with the height of the insertion hole (21) on the freezing box (20).

7. The method of claim 1, wherein, When used for simulating glaze ice, the temperature of the freezing box (20) is set to -10℃ to -5℃, and the humidity is not less than 80% RH; or when used for simulating rime, the temperature of the freezing box (20) is set to less than -10℃, and the humidity is less than 50% RH.

8. An apparatus for multi-layered strand ice adhesion strength testing, characterized by, The device comprises a stranded wire placement mold (10), a freezing box (20), a thrust sensor (30) and an experimental platform (40); The stranded wire placement mold (10) is a cubic structure as a whole, and a semicircular groove is arranged on the surface for placing the stranded wire to be tested; the size of the semicircular groove is designed to be slightly larger than the diameter of the stranded wire to be tested so that it is not easy to slide; The experimental platform (40) comprises a 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); The freezing box (20) is placed on the flat plate (41) of the experimental platform (40) and used for freezing the multi-layered stranded wire to be tested; one insertion hole (21) is arranged on the side of the freezing box (20) and used for inserting the metal push rod (31) of the push sensor (30) during testing; The device further comprises a clamp (50) used for fixing the multi-layered stranded wire to be tested on the flat plate (41); the clamp fixing member (51) of the clamp (50) is integrally formed as a disc-like structure and is provided with a circular hole in the middle for fixing the multi-layered stranded wire to be tested; a plurality of bolt inlets (53) are further arranged on the clamp fixing member (51) and used for inserting bolts; the clamp (50) is fixed on the track of the flat plate (41) through the clamp support member (52).

9. The apparatus of claim 8, wherein, The height of the circular hole on the clamp fixing member (51) is substantially consistent with the height of the insertion hole (21) on the freezing box (20).

10. Application of the multi-layered stranded wire with an ice adhesion strength result screened by the method of claim 3 and adopted in the preparation of an anti-icing wire.

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