Device and method for measuring ice adhesion strength of elastic coating under action of periodic external force

Abstract

The invention discloses a device and a method for measuring the ice adhesion strength of an elastic coating under the action of periodic external force. The device comprises a refrigeration module, an ice adhesion strength measuring module and a control system, in the refrigeration module, a cooling liquid channel is arranged in the test base, the cooling liquid channel is connected with a refrigerating unit, and temperature equalizing table temperature measuring points are arranged in the temperature equalizing table at equal intervals in the vertical direction; the ice adhesion strength measuring module comprises an elastic coating arranged on the surface of the temperature equalizing table and a mold placed on the surface of the elastic coating, the two sides of the mold are connected with teletransmission tension meters through pull wires respectively, and each teletransmission tension meter is arranged on the motion platform; the control system controls all the modules to work coordinately, adjusts the refrigerating capacity to control the surface temperature of the low-temperature test, controls the size and frequency of the periodic acting force, collects and records data and calculates the ice adhesion strength. According to the invention, measurement and influence mechanism research on the ice adhesion strength of the elastic coating surface under different temperature conditions under the action of periodic external force can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of ice adhesion measurement, and in particular relates to a device and method for measuring ice adhesion strength of an elastic coating under the action of periodic external force. Background Art

[0002] Icing is a common natural phenomenon that is prevalent in the engineering field and can cause inconvenience and harm, such as icing on aircraft wings in the aviation field, icing on wind turbine blades in the power field, and icing on the surface of refrigeration equipment. Since the icing process is accompanied by the occurrence of ice adhesion, it will cause the load on the material surface to increase, or block the material surface, interfere with the refractive ability and light transmittance of optical materials, etc. Therefore, how to efficiently and quickly evaluate the ice adhesion strength of the material surface is the basis for evaluating and designing deicing methods.

[0003] Ice adhesion strength is an important reference quantity for characterizing the anti-icing properties of material surfaces. Current ice adhesion measurement devices mostly use the centrifugal rotation method or the normal ice pushing method.

[0004] The centrifugal rotation method uses the centrifugal force generated by rapid rotation to make the icicle fly outward and hit the sensor on the cavity wall, and then calculate the ice adhesion strength; the normal push ice method uses a dynamometer probe to push the frozen icicle on the sample surface. The data measured by the dynamometer when the icicle is pushed away is the ice adhesion strength on the material surface. In summary, its technical characteristics are to monotonically increase the force on the icicle sample until the critical value of detachment. However, its limitation is that it cannot simulate the periodic external forces that may occur in practice. For example, during the operation of the wind turbine, the gravity and centrifugal force on the ice cubes during the rotation of the blades during icing are combined into a periodic external force. When the blades are facing downward, the gravity and centrifugal force are in the same direction, and when the blades are facing upward, the gravity and centrifugal force are in opposite directions, and the external force on the ice cubes changes periodically; when the transmission cable is frozen in winter, the wind blows through the frozen cable to form a periodic excitation force; there is also a technology that uses mechanical excitation force to make the ice on the surface of the object fall off, all of which require accurate knowledge of the ice adhesion strength data of the material under the action of periodic external forces.

[0005] The existing wind turbine deicing technologies can be divided into two categories: active and passive. Coating deicing belongs to the category of passive deicing. Among them, the bonding force between the elastomer and the ice is the smallest, and it has good anti-icing performance. Studies have shown that the use of super-hydrophobic coatings can reduce the ice adhesion strength to 50kPa, the use of lubricating coatings can reduce the ice adhesion strength to 16kPa, and the use of elastic coatings can reduce the ice adhesion strength to 0.2kPa. Therefore, hydrophobic elastic coatings have become an emerging anti-icing coating material in recent years. It uses the local stress generated by uneven stiffness to reduce the adhesion between the ice layer and the coating, and can effectively reduce the ice adhesion strength under the action of periodic external forces.

[0006] Therefore, how to provide an ice adhesion strength testing device and method with good operability and repeatability that can simulate the action of periodic external forces, accurately measure the ice adhesion strength of the elastic coating surface under the action of periodic external forces, study the change mechanism of ice adhesion strength of the elastic coating, and is an issue that needs to be urgently addressed by technicians in this field. Summary of the invention

[0007] The present invention provides a device and method for measuring the ice adhesion strength of an elastic coating under the action of a periodic external force, which can realize the measurement of the ice adhesion strength of the elastic coating surface under different temperature conditions under the action of a periodic external force and the study of the influencing mechanism, and can ensure the accuracy of the measurement results, and has good operability and repeatability.

[0008] A device for measuring ice adhesion strength of elastic coating under periodic external force, comprising a refrigeration module, an ice adhesion strength measurement module and a control system;

[0009] The refrigeration module comprises a refrigeration unit, a test base and a temperature-averaging platform; the temperature-averaging platform is arranged on the test base, a coolant channel is arranged in the test base, the coolant channel is connected to the refrigeration unit, and an inlet temperature measuring point and an outlet temperature measuring point are arranged at the inlet and outlet of the coolant channel; three temperature measuring points of the temperature-averaging platform are arranged at equal intervals in the vertical direction inside the temperature-averaging platform; a sealing cover is arranged on the temperature-averaging platform, and nitrogen is introduced into the sealing cover to block the air; the outside of the test base and the side of the temperature-averaging platform are wrapped with an insulation layer;

[0010] The ice adhesion strength measurement module includes an elastic coating arranged on the surface of the temperature-averaging platform and a mold placed on the surface of the elastic coating. The centers of both sides of the mold are respectively connected to corresponding remote tensile gauges through traction lines, and each remote tensile gauge is arranged on a motion platform.

[0011] The control system controls the cooling capacity of the refrigeration unit through temperature feedback from the liquid inlet temperature measuring point, the liquid outlet temperature measuring point and the temperature measuring point of the temperature equalizing platform, thereby maintaining the temperature of the surface of the temperature equalizing platform constant at the set test temperature. The movement of the two motion platforms is controlled through the tension feedback of two remote-transmitting tensile gauges, thereby controlling the tension on the ice to change periodically as set. Finally, data is collected and recorded and the ice adhesion strength is calculated.

[0012] Furthermore, a vertically placed background board and a parallel light source facing the background board are respectively provided on the front and rear sides of the traction line, and the angle between the traction line and the horizontal plane is determined by the shadow formed by the traction line illuminated by the parallel light source.

[0013] Furthermore, the three temperature measurement points of the temperature-averaging platform are used to calculate the surface temperature of the temperature-averaging platform (102) according to the law of heat conduction. The specific process is as follows:

[0014] The side of the temperature-averaging platform is wrapped with an insulation layer, so that the temperature-averaging platform transfers heat only by heat conduction in the height direction, there is no heat exchange in the surrounding directions, and the temperature of the upper and lower surfaces remains constant. Fourier's heat conduction law is used to solve the temperature distribution, which satisfies the heat conduction equation:

[0015]

[0016] The solution to the heat conduction equation is a linear function:

[0017] T(z)=az+b

[0018] Where, T(z) is the temperature distribution in the height direction, z is the coordinate in the height direction; a and b are constants;

[0019] Therefore, the surface temperature of the temperature-averaging platform is calculated based on the fitting function of the temperature measurement point and the distribution position. This solution avoids the influence of contact thermal resistance in traditional measurement methods such as thermocouples, and uses multiple temperature measurement point fitting function methods to reduce the influence of accidental errors.

[0020] Furthermore, the motion platform comprises a three-dimensional displacement platform, an angle tilting platform and a remote-controllable electric displacement platform which are arranged in sequence from bottom to top, and the remote-transmittable dynamometer is arranged on the remote-controllable electric displacement platform;

[0021] The remote data transmission force gauge is used to measure the tension applied to the mold; the remote control electric displacement platform controls the tension applied to the mold by controlling the displacement of the remote data transmission force gauge; the angle tilting platform is used to adjust the angle of the remote data transmission force gauge and the remote control electric displacement platform to keep them parallel to the traction line direction; the three-dimensional displacement platform is used to adjust the horizontal and vertical positions so that the traction line and the horizontal plane form the angle required for the test.

[0022] Furthermore, a microscope is provided above the mold, which is used to measure the tiny displacement of the ice cube and the microstructural changes of the elastic coating at the adhesion point between the ice cube and the elastic coating, so as to study the mechanism of the influence of periodic external force on the ice adhesion strength.

[0023] Preferably, a rotating and tortuous cooling liquid channel is provided in the test base.

[0024] A method for measuring ice adhesion strength under periodic external force, using the above-mentioned device for measuring ice adhesion strength of elastic coating under periodic external force, comprises the following steps:

[0025] S1, set the temperature and tension cycle mode, control the operation of the refrigeration unit and transport the refrigerant through the coolant channel in the test base, calculate the surface temperature of the temperature table through the temperature measurement point of the temperature table, compare it with the set temperature and control the cooling capacity of the refrigeration unit according to the comparison result, so that the temperature table is stable at the test temperature;

[0026] S2, fixing the elastic coating on a temperature-averaging platform, placing the mold on the elastic coating, dropping water drops on the elastic coating in the mold to form a water film, and waiting for the water film to condense into ice;

[0027] S3, control the height of the remote-controllable electric translation stage, and at the same time measure the angle between the projection of the traction line on the background board and the horizontal line under the illumination of the parallel light source, and adjust the height to the test setting angle;

[0028] S4, control the remote-controllable electric translation stage to drive the remote-transmitting tensile gauge to move, measure the displacement of ice and the microstructural changes of the elastic coating through a microscope, monitor the tension data of the remote-transmitting tensile gauge, control the tension to cycle periodically within the set range for a set number of times, gradually increase the tension until the mold and the elastic coating are pulled apart, record the data of the remote-transmitting tensile gauge, and calculate the ice adhesion strength.

[0029] The ice adhesion strength was calculated according to the following formula:

[0030]

[0031] Among them, σ T,cyc is the ice adhesion strength at temperature T, F cyc It is the maximum pulling force recorded by the remote data transmission dynamometer when the mold is pulled off after the periodic external force, θ is the angle between the traction line and the horizontal plane, and S is the ice area in the mold.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention controls the refrigeration system according to the temperature feedback of the temperature measuring point through the control system and adopts the temperature-averaging platform material with high thermal conductivity, so as to accurately control the test surface temperature to be stabilized at any set temperature within a controllable range, thereby improving the accuracy and stability of the measurement data of the ice adhesion strength on the surface of the material to be tested.

[0034] The present invention coordinates the work of the mold, the motion platform and the temperature-averaging platform with the control system to accurately control the ice adhesion area, the tension angle and the test temperature, thereby effectively improving the diversity, operability and repeatability of the test. The present invention simulates the ice adhesion strength measurement under the periodic external force under the periodic action of centrifugal force and gravity on ice-covered fan blades that may occur under real conditions. The present invention is an ice adhesion strength test system with a wide range of applications, high measurement accuracy, strong versatility, simple installation and easy carrying. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a schematic structural diagram of a device for measuring ice adhesion strength of an elastic coating under periodic external force.

[0036] Figure 2 It is a schematic diagram of the structure of the test base in the present invention.

[0037] Figure 3 It is a schematic diagram of the positional relationship among the parallel light source, the traction line and the background plate in the present invention.

[0038] Figure 4 The force analysis of ice coating on wind turbine blades during rotation is carried out for real application.

[0039] Figure 5 The present invention is a flow chart of a method for measuring ice adhesion strength of an elastic coating under periodic external force.

[0040] In the figure: 101-test base, 102-temperature balance table, 103-cooling liquid channel, 104-sealing groove, 105-sealing strip, 106-liquid inlet, 107-liquid outlet, 108-insulation layer, 109-sealing cover, 201-refrigeration unit, 202-liquid inlet pipe, 203-liquid inlet temperature measuring point, 204-liquid outlet pipe, 205-liquid outlet temperature measuring point, 301, 302, 303-temperature measuring point of temperature balance table, 4-elastic coating, 5-mold, 6-traction line, 7-background plate, 8-parallel light source, 901, 905-three-dimensional displacement table, 902, 906-angle tilting platform, 903, 907-remotely controllable electric displacement table, 904, 908-remotely transmittable dynamometer, 10-microscope, 11-control system. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be pointed out that the embodiments described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0042] like Figure 1 to Figure 3 As shown, a device for measuring ice adhesion strength of elastic coating under periodic external force, comprising:

[0043] The controllable low temperature test platform includes a test base 101, a temperature platform 102, a coolant channel 103, a sealing groove 104, a sealing strip 105, a liquid inlet 106, a liquid outlet 107, an insulation layer 108, and a sealing cover 109. A tortuous coolant channel 103 is used to ensure that the refrigerant is fully heat exchanged in the test base 101, and the surrounding area except the surface of the temperature platform 102 is covered with an insulation layer 108 to improve the control accuracy of the controllable low temperature test platform; the temperature platform 102 is made of copper material, which has excellent thermal conductivity, ensuring that the temperature distribution on the surface of the temperature platform is uniform and the temperature control is accurate; the sealing cover 109 is set on the upper surface of the test platform and filled with nitrogen to reduce the influence of water vapor condensation in the air on the ice adhesion strength test.

[0044] Refrigeration system, the refrigeration unit 201 is connected to the controllable low-temperature test platform through the liquid inlet pipe 202 and the liquid outlet pipe 204. The inlet temperature measuring point 203 and the outlet temperature measuring point 205 are respectively set on the pipeline to monitor the refrigerant temperature of the inlet and outlet pipes. The refrigeration capacity of the refrigeration unit 201 is adjusted according to the difference between the surface temperature of the temperature-averaging platform 102 and the set temperature calculated by the control system 11.

[0045] The temperature measurement points 301, 302, and 303 of the temperature-averaging platform are evenly spaced in the vertical direction within the temperature-averaging platform 102. According to the Fourier heat conduction law in a one-dimensional steady state with constant physical properties and no internal heat source, the temperature distribution function of the temperature-averaging platform 102 along the height direction can be fitted:

[0046]

[0047] The solution to the heat conduction equation is a linear function:

[0048] T(z)=az+b

[0049] Among them, T(z) is the temperature distribution in the height direction, z is the coordinate in the height direction, a and b are constants, and then the surface temperature of the temperature-averaging platform 102 is calculated. This temperature measurement method avoids the error caused by poor contact of the thermal resistor and improves the accuracy and reliability of the temperature measurement of the temperature-averaging platform surface.

[0050] The elastic coating 4 is disposed on the surface of the temperature-averaging platform 102 and is tested using new materials such as an elastic deicing coating.

[0051] Mold 5, which has a size of 5cm×5cm×5cm, is placed on the surface of the elastic coating 4. Water drops are dripped from above and condensed under the restriction of mold 5 to form ice cubes with a fixed bottom area, thereby controlling the test variables and facilitating analysis and calculation.

[0052] The two ends of the traction lines 601 and 602 are connected to the center of the side of the mold 5 and the hooks of the remote transmission tension gauges 904 and 908.

[0053] The background plate 7 is vertically located 5 to 15 cm behind the traction line, and the parallel light source 8 is vertically located 40 to 50 cm in front of the traction line. The parallel light source 8 emits parallel light to illuminate the traction line and produces a projection on the background plate 7. The angle formed by the projection and the horizontal plane can be measured to obtain the angle between the traction line and the horizontal plane, so as to further test the influence of traction forces at different angles on the ice adhesion strength.

[0054] The remote transmission force gauges 904 and 908 are connected to the mold 5 through the traction line, measure the traction force on the ice cube and transmit the data to the control system 11. The remote control electric displacement tables 903 and 907 are arranged below the remote transmission force gauges 904 and 908, and are controlled by the control system 11 to drive the remote transmission force gauges 904 and 908 to move. The displacement speed is 0.5 mm / s during the tension cycle, and is reduced to 0.2 mm / s when the tension reaches 80% of the set range. The displacement stops immediately when the tension reaches the set range, ensuring that the tension changes stably during the cycle, and the error between the actual cycle range and the set range of the tension is controlled within ±0.2N. After the cycle is completed, the displacement speed is maintained at 0.5 mm / s during the pulling process until the pulling stops, so as to control the traction force on the ice cube. The three-dimensional displacement tables 901 and 905 are arranged below the remote control electric displacement table, and their positions and heights are adjusted to ensure that the tension measurement has a suitable initial position and the tension angle required for the test. The angle of the platforms 902 and 906 is tilted, and the angle of the remote-transmitting force gauges 904 and 908 is adjusted to make them parallel to the angle between the traction line and the horizontal plane, ensuring that the measured tension is the actual tension value on the traction line. The ice adhesion strength test module can be used to simulate the periodic external forces acting on ice in reality, such as the stress on wind turbine blades and transmission lines.

[0055] like Figure 4 As shown in the figure, the force on the tip of the wind turbine blade covered with ice in real conditions is affected by gravity and centrifugal force. Assuming that the distance between the center of gravity of the ice and the center of rotation is R, the angle between the blade and the vertical direction is α, the blade rotation speed is ω, and the mass of the ice is m, through force analysis, it can be obtained that the force on the ice in the radial direction has an equation:

[0056] F r =ω 2 Rm+mgcosα

[0057] α=ωt

[0058] There are extreme values ​​in the vertical direction:

[0059] F r,max =m(ω 2 R+g)

[0060] F r,min =m(ω 2 Rg)

[0061] Taking the Siemens Gamesa SG 2.1-114 wind turbine as an example, its blade length is 57m. At a rotation speed of 12rpm, it can be calculated that the force range in the vertical direction is 80.2m to 99.82m (assuming the radial direction is the positive direction). The ice is affected by gravity that cycles periodically with the circular motion.

[0062] Under the stimulation of wind, ice-covered conductors experience a low-frequency, large-amplitude self-excited vibration called ice dancing. The ice on the conductor is subjected to a periodic force of gravity, aerodynamic force, and inertia as the conductor vibrates.

[0063] The gravity is constant and vertically downward, with a magnitude of G = mg;

[0064] Air power Among them C D is the drag coefficient, ρ a is the air density, is the wind speed, and A is the reference area (windward cross-sectional area).

[0065] The wire vibration is described by simple harmonic vibration, and the change of displacement over time can be expressed as:

[0066] x(t)=Acos(ωt+φ)

[0067] Among them, x(t) is the change of position with time t, A is the amplitude, ω is the angular frequency, t is the time, and φ is the initial phase.

[0068] Taking the second derivative with respect to time gives the expression for acceleration:

[0069] a(t)=-ω 2 Acos(ωt)

[0070] The inertia force expression is:

[0071] F(t)=m·a(t)=-mω 2 Acos(ωt)

[0072] In actual situations, the effect of aerodynamics on icing can be ignored compared to the inertial force, so the conductor icing can be regarded as the combined effect of the periodic inertial force and gravity.

[0073] Through the linkage control of the remote-transmittable tensile gauges 904 and 908, the remote-controllable electric displacement platforms 903 and 907 and the control system 11 on both sides, in the case that the pulling direction may change, after the test starts, the remote-controllable displacement platform on one side drives the remote-transmittable tensile gauge to provide pulling force according to the scheme to gradually reach the set value, and the traction line on the other side is kept in a relaxed state. After stabilization, the controllable electric displacement platform on the traction side moves in the reverse direction until the traction force on this side gradually decreases to 0, and the remote-controllable electric displacement platform on the opposite side starts to drive the remote-transmittable tensile gauge to gradually increase the pulling force to the set value. After stabilization, it moves in the reverse direction until the traction force on this side gradually decreases to 0. This process is repeated for a specified number of cycles, and the pulling force on one side gradually increases until the ice is pulled off, and the ice adhesion under the action of periodic external force is measured;

[0074] When the pulling force direction does not change, the remote-controllable displacement platform on one side drives the remote-transmitting tensile force meter to provide a pulling force gradually reaching the set value according to the scheme, and the traction line on the other side is kept in a relaxed state. After stabilization, the controllable electric displacement platform on the traction side moves in the opposite direction until the traction force on this side gradually decreases to the set minimum value. This process is repeated for a specified number of cycles, and the pulling force gradually increases until the ice is pulled off, and the ice adhesion force under the action of periodic external force is measured;

[0075] In this way, the periodic external force cycles in real situations can be simulated on a small scale, and the changes in ice adhesion strength under the action of periodic external forces can be studied.

[0076] The microscope 10 is arranged in the sealing cover 109, and amplifies the microstructure of the bonding point between the ice cube and the elastic coating 4, measures and records the tiny displacement and deformation of the ice cube during the periodic change process. Through the calibrated microscope 10, the tiny displacement distance of the ice cube under the influence of tension during the cycle process can be directly read, and the microstructure changes of the coating at the bonding point with the elastic coating 4 during the observation process can be analyzed, thereby analyzing the action process and mechanism of the periodic external force on the ice adhesion strength.

[0077] The control system 11 controls the refrigeration capacity of the refrigeration unit through temperature feedback from the liquid inlet temperature measuring point 203, the liquid outlet temperature measuring point 205 and the temperature measuring point of the temperature equalizing platform, thereby maintaining the temperature of the surface of the temperature equalizing platform of the controllable low-temperature test platform constant at the set test temperature, and controls the displacement of the remote-controlled electric displacement platform 903, 907 through the tension feedback of the remote-transmittable tension gauges 904, 908, thereby controlling the tension on the ice to change periodically as set.

[0078] An automatic testing method for ice adhesion strength under periodic external force, using the above-mentioned testing device to perform the following testing steps:

[0079] Step S1: setting the test temperature and the range f of periodic changes in the tension on the ice cube, the number of cycles n and the change mode in the control system 11.

[0080] Step S2: Place the elastic coating 4 on the surface of the temperature-averaging platform 102 and place the mold 5 on the elastic coating 4, while ensuring that the top surface of the elastic coating 4 is flat, free of impurities and scratches, and ensuring that the measured data is not affected by friction and other forces.

[0081] Step S3: Turn on the refrigeration system, wait for the control system 11 to control the surface temperature of the temperature-averaging platform 102 to stabilize at the set temperature, drop water into the mold 5 to condense it into an ice cube with a fixed shape, and after the ice cube is condensed, close the sealing cover 109, fill it with nitrogen, and exhaust the air to ensure that the test process is not affected by the condensation of water vapor in the air.

[0082] Step S4: Set the parallel light source 8 and the background plate 7, keep them vertically located on both sides of the traction line, adjust the three-dimensional displacement stage 901, 905, drive the tension test module to move, adjust the height and measure the angle between the projection of the traction line on the background plate 7 and the horizontal plane to reach the angle θ required for the test, adjust the horizontal position so that the tension of the remote-transmitting tensile gauges 904, 908 is 0, and adjust the position of the microscope 10 so that its zero scale line coincides with the edge of the ice cube.

[0083] Step S5: The control system 11 controls the remote-controllable electric displacement stage 903, 907 to drive the remote-transmitting tensile gauges 904, 908 to move at the speed, and at the same time observes and records the micro-displacement and micro-structural changes of the ice cube through the microscope 10, controls the tension on the traction line to cycle periodically within the set range for a set number of times, and gradually increases the tension until the mold 5 and the elastic coating 4 are pulled apart, and records the data of the remote-transmitting tensile gauges 904, 908, the maximum value of which is F cyc , and calculate the ice adhesion strength based on the ice area S in the mold:

[0084] The calculation formula of ice adhesion strength is:

[0085] Among them, if the ice cubes do not fall off during the cycle, it indicates that the measured tension is the ice adhesion force between the ice and the surface of the elastic coating 4, and the test result is considered valid; if the ice cubes fall off during the cycle, it means that the tension cycle range is set too large, and the test result is considered invalid. At this time, it is necessary to reset the cycle range according to the maximum tension recorded by the remote tensile meter 903 in this test and the tension when it is pulled off, and then repeat steps S2 to S5.

[0086] In which, in step S1, no loop setting is performed, steps S2 to S4 are repeated, and in step S5, the pulling force is gradually increased until the ice cube is pulled off from the elastic coating, and the remotely transmittable tensile meter data is recorded, the maximum value of which is F, and the ice adhesion strength is calculated based on the ice area S in the mold.

[0087] The calculation formula for the general ice adhesion strength without periodic external force cycles is: The ice adhesion strength σ under the periodic external force T,cyc Comparative analysis.

[0088] Among them, the cycle setting in step S1 can set a corresponding cycle mode in the control system 11 according to the force mode of ice cubes in actual situations, and by simulating the tension change mode, the tension action angle, etc., the state of ice adhesion strength of the elastic coating under the periodic external force in actual applications can be restored to the maximum extent;

[0089] Among them, as the tension cycle is carried out, the tiny displacement distance of the ice cube under the microscope 10 and the microstructural morphology of the bonding point with the elastic coating 4 are recorded in each cycle, and the change pattern as the cycle proceeds is studied. The number of cycles and the size of the cyclic tension are changed, and the tiny displacement distance of the ice cube and the difference in microstructural changes under different periodic external forces are studied. Combined with the data obtained from the final test, the influence mechanism of periodic external force on the ice adhesion strength of the elastic coating is studied.

[0090] The test device and test method can obtain different test conditions by adjusting the height of the three-dimensional displacement stage 901, 905, the surface temperature of the temperature-averaging stage 102, the range and number of tension periodicity, and the four types of elastic coatings, and have high operability, versatility, and repeatability.

[0091] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for measuring ice adhesion strength of elastic coating under periodic external force, characterized in that: It comprises a refrigeration module, an ice adhesion strength measurement module and a control system (11); The refrigeration module comprises a refrigeration unit, a test base (101) and a temperature-averaging platform (102); the temperature-averaging platform (102) is arranged on the test base (101), a cooling liquid channel (103) is arranged in the test base (101), the cooling liquid channel (103) is connected to the refrigeration unit, and an inlet temperature measuring point and an outlet temperature measuring point are arranged at the inlet and outlet of the cooling liquid channel (103); three temperature-averaging platform temperature measuring points are arranged at equal intervals in the vertical direction inside the temperature-averaging platform (102); a sealing cover (109) is arranged on the temperature-averaging platform (102), and nitrogen is introduced into the sealing cover (109) to block air; the outside of the test base (101) and the side of the temperature-averaging platform (102) are wrapped with a thermal insulation layer (108); The ice adhesion strength measurement module comprises an elastic coating (4) arranged on the surface of a temperature-averaging platform (102) and a mold (5) placed on the surface of the elastic coating (4), the centers of both sides of the mold (5) are respectively connected to corresponding remote-transmitting tensile gauges through traction lines, and each remote-transmitting tensile gauge is arranged on a motion platform; The control system (11) controls the refrigeration capacity of the refrigeration unit through temperature feedback of the liquid inlet temperature measuring point, the liquid outlet temperature measuring point and the temperature measuring point of the temperature equalizing platform, thereby maintaining the temperature of the surface of the temperature equalizing platform (102) constant at a set test temperature, and controls the movement of the two motion platforms through the tension feedback of two remotely transmittable tension gauges, thereby controlling the tension on the ice to change periodically according to the setting, and finally collecting and recording data and calculating the ice adhesion strength.

2. The device for measuring ice adhesion strength of elastic coating under periodic external force according to claim 1, characterized in that: A vertically placed background plate (7) and a parallel light source (8) facing the background plate (7) are respectively provided on the front and rear sides of the traction line. The angle between the traction line and the horizontal plane is determined by the shadow formed by the traction line illuminated by the parallel light source (8).

3. The device for measuring ice adhesion strength of elastic coating under periodic external force according to claim 1, characterized in that: The three temperature measurement points of the temperature-averaging platform are used to calculate the surface temperature of the temperature-averaging platform (102) according to the law of heat conduction. The specific process is as follows: The side of the temperature-averaging platform (102) is wrapped with an insulation layer (108), so that the temperature-averaging platform (102) transfers heat only by heat conduction in the height direction, and there is no heat exchange in the surrounding directions. The temperatures of the upper and lower surfaces are kept constant. The temperature distribution is solved by applying Fourier's heat conduction law to satisfy the heat conduction equation: The solution to the heat conduction equation is a linear function: T(z)=az+b Where, T(z) is the temperature distribution in the height direction, z is the coordinate in the height direction; a and b are constants; Therefore, the surface temperature of the temperature-averaging platform is calculated based on the fitting function of the temperature measurement point and the distribution position.

4. The device for measuring ice adhesion strength of elastic coating under periodic external force according to claim 1, characterized in that: The motion platform comprises a three-dimensional displacement platform, an angle tilting platform and a remote-controllable electric displacement platform which are arranged in sequence from bottom to top, and the remote-transmitting dynamometer is arranged on the remote-controllable electric displacement platform; The remote data transmission tensile gauge is used to measure the magnitude of the tensile force applied to the mold (5); the remote controllable electric displacement platform controls the magnitude of the tensile force applied to the mold by controlling the displacement of the remote data transmission tensile gauge; the angle tilting platform is used to adjust the angle of the remote data transmission tensile gauge and the remote controllable electric displacement platform to keep them always parallel to the direction of the traction line; the three-dimensional displacement platform is used to adjust the horizontal and vertical positions so that the traction line and the horizontal plane form the angle required for the test.

5. The device for measuring ice adhesion strength of elastic coating under periodic external force according to claim 1, characterized in that: A microscope (10) is arranged above the mold (5), and the microscope (10) is used to measure the tiny displacement of the ice cube and the microscopic structural change of the elastic coating at the adhesion point between the ice cube and the elastic coating, so as to study the mechanism of the influence of periodic external force on the ice adhesion strength.

6. The device for measuring ice adhesion strength of elastic coating under periodic external force according to claim 1, characterized in that: A rotating and tortuous cooling liquid channel (103) is provided in the test base (101).

7. A method for measuring ice adhesion strength under periodic external force, characterized in that: The device for measuring ice adhesion strength of elastic coating under periodic external force according to any one of claims 1 to 6 comprises the following steps: S1, set the temperature and tension cycle mode, control the operation of the refrigeration unit and transport the refrigerant through the coolant channel in the test base, calculate the surface temperature of the temperature table through the temperature measurement point of the temperature table, compare it with the set temperature and control the cooling capacity of the refrigeration unit according to the comparison result, so that the temperature table is stable at the test temperature; S2, fixing the elastic coating on a temperature-averaging platform, placing the mold on the elastic coating, dropping water drops on the elastic coating in the mold to form a water film, and waiting for the water film to condense into ice; S3, control the height of the remote-controllable electric translation stage, and at the same time measure the angle between the projection of the traction line on the background board and the horizontal line under the illumination of the parallel light source, and adjust the height to the test setting angle; S4, control the remote-controllable electric translation stage to drive the remote-transmitting tensile gauge to move, measure the displacement of ice and the microstructural changes of the elastic coating through a microscope, monitor the tension data of the remote-transmitting tensile gauge, control the tension to cycle periodically within the set range for a set number of times, gradually increase the tension until the mold and the elastic coating are pulled apart, record the data of the remote-transmitting tensile gauge, and calculate the ice adhesion strength.

8. The method for measuring ice adhesion strength under periodic external force according to claim 7, characterized in that: The ice adhesion strength was calculated according to the following formula: Among them, σ T,cyc is the ice adhesion strength at temperature T, F cyc It is the maximum pulling force recorded by the remote data transmission dynamometer when the mold is pulled off after the periodic external force, θ is the angle between the traction line and the horizontal plane, and S is the ice area in the mold.

Images