Magnetorheological fluid adaptive anti-icing wind turbine blade and control method

Abstract

The application belongs to the technical field of wind power generation equipment anti-icing, and particularly relates to a magnetorheological fluid self-adaptive anti-icing wind turbine blade and a control method. The wind turbine blade comprises a shell, a girder installed in the shell, a web plate connected with the girder, a core material spaced from the web plate, and an electromagnet connected with the web plate. A cavity area is formed in the leading edge area of the shell, and a MRF interlayer and a skin are attached to each other and installed in the cavity area. A PLC controller for controlling the electromagnet is installed in the root of the shell. When the electromagnet is started, the MRF interlayer is solidified by the magnetic field of the electromagnet to extrude the external ice layer. Conversely, when the electromagnet is dormant, the MRF interlayer returns to a liquid state, so that the aerodynamic form of the blade is maintained after ice removal. The control method comprises steps one to seven. The application utilizes the transient solidification characteristics of the magnetorheological fluid under the action of the magnetic field to dynamically regulate the surface form of the blade, destroy the continuity of the ice layer, and restore the aerodynamic smoothness in the ice-free state.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wind power generation equipment anti-icing, and particularly relates to a magneto-rheological fluid self-adaptive anti-icing wind turbine blade and a control method. BACKGROUND

[0002] The wind turbine blade is prone to icing in a high-humidity environment of-30 DEG C to 0 DEG C, and the traditional anti-icing technology faces significant challenges, such as the energy consumption of more than 100 kW per unit for electric heating deicing, and the heating element is prone to aging and damage in long-term operation; although the application of super-hydrophobic coating can reduce water droplet adhesion, the inhibition effect on medium-thick ice (ice thickness>1 mm) is limited, and the corresponding ice layer adhesion force still reaches more than 15 kPa; mechanical vibration deicing needs an additional power source, and the system is complex and the energy utilization rate is less than 30%.

[0003] At present, intelligent electric control mechanical ice breaking is mainly used to break the ice layer, but the existing scheme has defects such as response time interval>10 s, single form regulation only smooth-rough conversion can be realized, high energy consumption, etc. For example, the anti-icing structure based on shape memory alloy has fixed phase transition temperature and cannot be dynamically adjusted according to the environment, and the response time is as long as 30 s, which is difficult to cope with the rapid icing scene; for example, the anti-icing device and method capable of adjusting with sea current for offshore wind power foundation are searched in the Chinese invention with the publication number CN117090247A, the impeller assembly can rotate and rise around the steel pipe pile under the impact of sea current in each direction, and the angle change between the upper and lower ice breaking rods can break the sea ice and reduce the probability of structural ice vibration; when the sea current action is weakened, the spring rebounds to press the movable collar to gradually return the anti-icing device to the original position.

[0004] When the wind turbine is in use, the intelligent electric control ice breaking rod is installed on the blade, which can automatically break the ice, but greatly increases the roughness of the blade surface, and when there is no ice, it produces obvious wind resistance, which is not conducive to the recovery of the aerodynamic smoothness of the blade after deicing, therefore, the application proposes a magneto-rheological fluid self-adaptive anti-icing wind turbine blade and a method for recovering the aerodynamic smoothness of the blade after deicing. SUMMARY

[0005] The purpose of the application is to provide a magneto-rheological fluid self-adaptive anti-icing wind turbine blade and a control method, which can utilize the transient solidification characteristics of the magneto-rheological fluid under the action of the magnetic field to dynamically regulate the surface form of the blade, break the continuity of the ice layer, and recover the aerodynamic smoothness in the ice-free state.

[0006] The technical scheme adopted by the application is as follows:

[0007] A magneto-rheological fluid self-adaptive anti-icing wind turbine blade comprises a shell, a girder is installed inside the shell, a web plate connected with the girder, a core material spaced from the web plate, and an electromagnet connected with the web plate.

[0008] Wherein, the front edge region of the shell is provided with a cavity area, the cavity area is installed with the MRF interlayer and the skin which are mutually attached, and the root of the shell is installed with a PLC controller for controlling the electromagnet;

[0009] When the electromagnet is started, the MRF interlayer is solidified by the magnetic field of the electromagnet to extrude the external attached ice layer, and vice versa, the electromagnet is dormant to restore the MRF interlayer to liquid state, so as to maintain the aerodynamic form of the blade after deicing.

[0010] As an optional solution, the front edge region of the shell is installed with a humidity sensor and a temperature sensor which are staggered from the position of the cavity area, and the humidity sensor and the temperature sensor are connected to the PLC controller;

[0011] Wherein, the humidity sensor and the temperature sensor monitor the temperature and humidity signals outside the blade and send them to the PLC controller for controlling the working state of the electromagnet.

[0012] As an optional solution, an alloy framework in a hollow shape is installed inside the girder along the axial direction of the shell, an insulating mounting frame for bearing the electromagnet is penetrated through the alloy framework, and a pawl in contact with the bottom wall of the alloy framework is fixed at the bottom of the insulating mounting frame.

[0013] As an optional solution, a moisture absorbing cotton strip surrounding the electromagnet and a water absorbing resin bead wrapped inside the moisture absorbing cotton strip are arranged at the top of the insulating mounting frame;

[0014] When the inside of the shell is damp, the moisture absorbing cotton strip and the water absorbing resin bead absorb moisture to separate the moisture from the electromagnet.

[0015] As an optional solution, a male plug and a female socket which are mutually inserted are further arranged inside the shell, the female socket is embedded in the alloy framework, and the male plug is connected to the moisture absorbing cotton strip;

[0016] When the male plug and the female socket are inserted, the humidity sensor and the temperature sensor are both electrified;

[0017] When the moisture absorbing cotton strip is damp, it is disconnected from the male plug, so that the male plug and the female socket are separated, so that the humidity sensor and the temperature sensor are de-energized and offline, indicating a fault signal.

[0018] As an optional solution, a memory spring connected to the alloy framework is sleeved outside the male plug, a water-soluble paper is sleeved outside the moisture absorbing cotton strip, and the male plug is connected to the moisture absorbing cotton strip through the water-soluble paper;

[0019] When the moisture-absorbing cotton strip is wet, the water-soluble paper contacts water to dissolve, so that the male plug is unlocked, and the male plug is separated from the female socket under the elastic potential energy of the memory spring.

[0020] As an alternative, a limiting ring in the shape of an opening is arranged between the moisture-absorbing cotton strip and the water-soluble paper, the bottom of the limiting ring is fixed to the top surface of the insulating mounting frame, and the outer side of the insulating mounting frame is fixed with a positioning node inserted into the opening of the limiting ring.

[0021] As an alternative, a control method of a magnetorheological fluid self-adaptive anti-icing wind turbine blade comprises the following steps:

[0022] Step one, pre-material: add carbonyl iron powder, dimethyl silicone oil and fumed silica into a vacuum stirrer to mix and prepare MRF, which is reserved for later use;

[0023] Step two, blade processing: during the molding stage of the blade composite material, a cavity area is reserved in the leading edge area of the shell, and the cavity area is filled with MRF by injection to form an MRF interlayer;

[0024] Step three, blade molding: after the cavity area is injected, a PET / ITO flexible conductive film is covered, the PET / ITO flexible conductive film is bonded with the shell through a hot pressing process to form a skin, and then a primer and a topcoat are sprayed in sequence for the remaining area of the blade surface;

[0025] Step four, magnetic field arrangement: embed electromagnets along the blade span, the electromagnets are connected to the PLC controller located at the blade root through shielded wires, install humidity sensors and temperature sensors on the leading edge and pressure surface of the blade, and the humidity sensors and temperature sensors are kept at a distance from the MRF interlayer to avoid magnetic field interference;

[0026] Step five, ice removal control: the PLC controller prewrites control logic, when the temperature signal and humidity signal exceed the threshold value, the PLC controller drives the electromagnets to apply a magnetic field to the MRF interlayer to make the MRF interlayer deform to break the ice layer; when the temperature signal does not exceed the threshold value, the PLC controller automatically cuts off the magnetic field to make the MRF interlayer restore to liquid state;

[0027] Step six, blade testing: install the blade test piece in the wind tunnel, simulate icing conditions, start the electromagnets, use a camera to record the solidification process of the MRF interlayer, verify the surface change of the MRF interlayer, and measure the ice layer adhesion force change through a tension meter; monitor the liquid state recovery of the MRF interlayer after removing the magnetic field;

[0028] Step seven, stability detection: the PLC controller adopts a pulse power supply mode with a duty cycle of 1:4, a power meter is used to monitor the average power consumption, the energy consumption of continuous operation for 24 hours, and 1000 times of magnetic field activation-off cycle test is carried out to verify the change of MRF solidification-liquid conversion efficiency, and the change of the adhesion between the skin and the shell is tested.

[0029] As an alternative, the carbonyl iron powder, dimethyl silicone oil and fumed silica in step one are mixed by stirring at a volume fraction ratio of 60%:30%:10%, the stirring is mixed at a speed of 2000 rpm for 30 min to prepare MRF, at this time, the zero field viscosity of MRF is 1.2 Pa·s, and the shear yield strength of MRF under 0.5T magnetic field is >50kPa.

[0030] As an alternative, when the temperature signal is <0℃ and the humidity signal is >80% in step five, the PLC controller outputs a 10kHz pulse signal to drive the electromagnet to maintain a 0.5T magnetic field strength;

[0031] When the temperature signal is ≥0℃, the PLC controller automatically cuts off the magnetic field, so that the MRF interlayer returns to a liquid state.

[0032] The technical effects obtained by the application are as follows:

[0033] The application provides a low-energy-consumption, fast-response and self-adaptive anti-icing wind turbine blade, which utilizes the transient solidification characteristics of the magnetorheological fluid under the action of a magnetic field, dynamically regulates the surface morphology of the blade, destroys the continuity of the ice layer, and restores the aerodynamic smoothness in the ice-free state, so that the problems of high energy consumption and slow response of the traditional technology are solved.

[0034] The electromagnet of the application adopts a pulse power supply mode with a duty cycle of 1:4, and the average power consumption is <5W / m², which is 70% lower than that of continuous power supply; the magnetic field distribution is dynamically adjusted according to the icing risk area, and the magnetic field is activated only in the area of 20cm-50cm of the leading edge of the blade, so that the invalid energy consumption is reduced.

[0035] The application arranges a moisture absorption and moisture-proof structure inside the blade, which can serve as a protective layer for the electromagnet to a certain extent, and is disconnected when it is wet, so that the temperature and humidity sensors are offline, a fault signal is indicated, maintenance personnel can check the state of the electromagnet, the humidity sensor and the temperature sensor in time, the wet electromagnet is replaced, and the leaking blade is repaired, so that the material basis for deicing of the blade is ensured, if the possibility of wetness inside the blade is excluded, the health status of the entire circuit needs to be checked, the real reason for the disconnection of the circuit is found out, and timely repair is carried out to restore the power supply. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1is a front view of a magnetorheological fluid self-adaptive anti-icing wind turbine blade in embodiment one of the present application;

[0037] Figure 2 is a sectional view of a magnetorheological fluid self-adaptive anti-icing wind turbine blade in embodiment one of the present application;

[0038] Figure 3 is a structural schematic diagram of a rib plate in embodiment one of the present application;

[0039] Figure 4 is a bottom view of a rib plate in embodiment one of the present application;

[0040] Figure 5 is a front view of a rib plate in embodiment one of the present application;

[0041] Figure 6 is a top view of an electromagnet in combination with a humidity sensor in embodiment one of the present application;

[0042] Figure 7 is a top view of an electromagnet in embodiment one of the present application;

[0043] Figure 8 is a bottom view of an electromagnet in embodiment one of the present application;

[0044] Figure 9 is a sectional view of an electromagnet in embodiment one of the present application;

[0045] Figure 10 is a structural schematic diagram of a male plug and a female socket in assembled state in embodiment one of the present application;

[0046] Figure 11 is a flow chart of a control method in embodiment two of the present application.

[0047] In the drawings, the components represented by the respective reference numerals are listed as follows:

[0048] 1, housing; 2, girder; 3, rib plate; 4, core material; 5, skin; 6, cavity area; 7, MRF interlayer; 8, electromagnet; 9, PLC controller; 10, humidity sensor; 11, temperature sensor; 12, alloy skeleton; 13, insulating mounting frame; 14, pawl; 15, moisture absorbing cotton bar; 16, water absorbing resin beads; 17, male plug; 18, female socket; 19, memory resilient member; 20, water-soluble paper; 21, limiting ring; 22, positioning node. DETAILED DESCRIPTION

[0049] In order to make the objects and advantages of the present application clearer, the present application will be specifically described below in conjunction with embodiments. It should be understood that the following text is only used to describe one or several specific embodiments of the present application, and does not strictly limit the specific protection scope claimed by the present application.

[0050] Embodiment one:

[0051] As Figures 1-10 shown, a magnetorheological fluid self-adaptive anti-icing wind turbine blade includes a shell 1, a girder 2 installed inside the shell 1, a web plate 3 connected to the girder 2, and a core material 4 spaced from the web plate 3. The shell 1, the girder 2, the web plate 3, and the core material 4 are prefabricated in a factory building in a modular manner. The shell 1 can be two half shells. After the girder 2 and the web plate 3 are assembled and fixed by bolting or welding, the core material 4 such as sponge or wood is filled, and the two half shells are then fitted to form a seamless blade, which is ready to be installed on a wind turbine.

[0052] Referring to the accompanying Figure 2 , Figure 3 and Figure 7 , this embodiment embeds a set of electromagnets 8 on the web plate 3, for example, one electromagnet 8 is arranged every 5 cm along the spanwise direction of the blade. The leading edge region of the shell 1 is provided with a cavity area 6, and the MRF sandwich layer 7 and the skin 5 are installed in the cavity area 6 to adhere to each other. A PLC controller 9 for controlling the electromagnets 8 is installed at the root of the shell 1. When the electromagnets 8 are activated, the MRF sandwich layer 7 is solidified by the magnetic field of the electromagnets 8 to squeeze the external ice layer. Conversely, when the electromagnets 8 are dormant, the MRF sandwich layer 7 returns to a liquid state, thereby maintaining the aerodynamic shape of the blade after deicing.

[0053] The skin 5 is made of PET / ITO and cut into pieces of a specified size, which are sequentially laid on the upper and lower surfaces of the MRF sandwich layer 7 to cover a flexible conductive film with a thickness of 0.1 mm, thereby serving as an electrode and a protective layer.

[0054] As an optional embodiment, the MRF sandwich layer 7 is mainly made of carbonyl iron powder, silicone oil, and a thickening agent. It can be attracted by the electromagnet 8 with a soft magnetic alloy Fe73.5Cu1Nb3Si13.5B9 as the core material after being energized, causing a sharp change in its surface roughness. It can be solidified to form a micron-level jagged rough surface within 20 ms, with a roughness Ra=5μm-10μm. The surface topography change can destroy the continuity of the ice layer, and the jagged structure after solidification can significantly reduce the adhesion of the ice layer, making the ice layer more likely to crack and fall off under the action of wind. At the same time, it can inhibit the uniform spreading of water droplets on the surface and reduce the ice thickness.

[0055] Referring to the accompanying Figure 1 , Figure 2 and Figure 3 , this embodiment embeds a set of electromagnets 8 on the web plate 3, for example, one electromagnet 8 is arranged every 5 cm along the spanwise direction of the blade. The leading edge region of the shell 1 is provided with a cavity area 6, and the MRF sandwich layer 7 and the skin 5 are installed in the cavity area 6 to adhere to each other. A PLC controller 9 for controlling the electromagnets 8 is installed at the root of the shell 1. When the electromagnets 8 are activated, the MRF sandwich layer 7 is solidified by the magnetic field of the electromagnets 8 to squeeze the external ice layer. Conversely, when the electromagnets 8 are dormant, the MRF sandwich layer 7 returns to a liquid state, thereby maintaining the aerodynamic shape of the blade after deicing., in order to fine control micron sawtooth rough surface, the embodiment in the front edge area of the shell 1 staggered cavity area 6 by screw installation of humidity sensor 10 and temperature sensor 11, edge sealant, humidity sensor 10 and temperature sensor 11 monitor the temperature and humidity signal outside the blade, due to humidity sensor 10 and temperature sensor 11 are signal connected PLC controller 9, can send temperature and humidity signal to PLC controller 9, for controlling the working state of electromagnet 8.

[0056] For example, when the dew point temperature < 0 ℃ and humidity > 80%, PLC controller 9 output 10 kHz pulse signal, duty ratio 1:4, drive electromagnet 8, maintain 0.5T magnetic field strength; when the dew point temperature ≥ 0 ℃ automatic cut off magnetic field, make MRF interlayer 7 restore liquid.

[0057] Refer to the attached Figure 4 , Figure 7 and Figure 8 , in order to keep the stability of electromagnet 8 with the blade rotation, the embodiment in the beam 2 inside along the axial direction of the shell 1 by bolt installation of hollow alloy skeleton 12, and in the factory on the alloy skeleton 12 through the insulating mounting frame 13 for carrying electromagnet 8, the insulating mounting frame 13 is glued to the alloy skeleton 12, and the pawl 14 is welded at the bottom of the insulating mounting frame 13, which is in contact with the bottom wall of the alloy skeleton 12, so that the insulating mounting frame 13 can be clamped with the electromagnet 8, and the pawl 14 can be fixed on the bottom wall of the alloy skeleton 12 by screw, so as to grasp the electromagnet 8 and prevent shaking.

[0058] Refer to the attached Figure 6 , Figure 7 and Figure 9 , the blade is exposed to sunlight and directly exposed to rain erosion, which may cause slight cracking and leakage. In order to prevent moisture, the embodiment is bonded with moisture absorbing cotton strip 15 and water absorbing resin beads 16 wrapped inside the moisture absorbing cotton strip 15 on the top of the insulating mounting frame 13, which can surround the electromagnet 8; when the inside of the shell 1 is damp, the moisture absorbing cotton strip 15 and the water absorbing resin beads 16 absorb moisture to separate the moisture and the electromagnet 8, effectively preventing the electromagnet 8 from contacting water and rusting due to oxidation.

[0059] Refer to the attached Figure 5 , Figure 6 and Figure 10, although the power supply of electromagnet 8, humidity sensor 10 and temperature sensor 11 is controlled by PLC controller 9, in order to ensure the independent power supply of humidity sensor 10 and temperature sensor 11 and prevent them from being interfered by electromagnet 8, male plug 17 and female socket 18 are arranged in the shell 1, female socket 18 is embedded in alloy framework 12, both female sockets 18 are electrically connected to PLC controller 9, male plug 17 is connected to moisture absorbing cotton 15, both male plugs 17 are electrically connected to humidity sensor 10 and temperature sensor 11 respectively; when male plug 17 and female socket 18 are plugged, humidity sensor 10 and temperature sensor 11 are powered on;

[0060] When moisture absorbing cotton 15 is wet, male plug 17 is disconnected from moisture absorbing cotton 15, male plug 17 and female socket 18 are separated, so that humidity sensor 10 and temperature sensor 11 are powered off and offline, indicating a fault signal, which facilitates maintenance personnel to check the status of electromagnet 8, humidity sensor 10 and temperature sensor 11 in time, replace wet electromagnet 8, and repair the blade that leaks, so as to ensure the material basis of blade deicing.

[0061] Referring to the accompanying drawings Figure 5 , Figure 6 and Figure 10 In order to ensure that the circuit is disconnected in time when it is wet, memory spring 19 connected with alloy framework 12 is arranged outside male plug 17, memory spring 19 made of memory alloy material is pre-bent to a certain degree, one end of memory spring 19 is firmly adhered outside male plug 17, and the other end is fastened to alloy framework 12 through a screw, water-soluble paper 20 is arranged outside moisture absorbing cotton 15, and male plug 17 is connected to moisture absorbing cotton 15 through water-soluble paper 20; in this way, when moisture absorbing cotton 15 is wet, water-soluble paper 20 contacts water and dissolves, no longer restricting memory spring 19, memory spring 19 quickly straightens, male plug 17 is unlocked, male plug 17 is separated from female socket 18 under the action of the elastic potential energy of memory spring 19, and is passively triggered, realizing the quick disconnection of the circuit of humidity sensor 10 and temperature sensor 11.

[0062] Of course, it should be noted that the disconnection of the circuit of humidity sensor 10 and temperature sensor 11 may also be caused by cable damage, power failure and other reasons, when checking, if the possibility of wetness in the blade is excluded, the health status of the entire circuit needs to be checked to find out the real reason for the disconnection of the circuit, and the power supply is restored in time.

[0063] Referring to the accompanying drawings Figure 6 , Figure 7 and Figure 8The water-soluble paper 20 is light and thin, and the limiting ring 21 in the form of an opening is arranged between the moisture-absorbing cotton bar 15 and the water-soluble paper 20 to prevent excessive pulling between the water-soluble paper 20 and the male plug 17 during installation of the water-soluble paper 20. The limiting ring 21 is adhered to the top surface of the insulating mounting frame 13, and after being adhered to the water-soluble paper 20, the limiting ring 21 can be pulled tight. In addition, the positioning node 22 is welded to the outside of the insulating mounting frame 13 and is inserted into the opening of the limiting ring 21, so that the water-soluble paper 20 can be quickly positioned at the end of the two ends, the positioning time is reduced, and the positioning is quick.

[0064] Example two:

[0065] As shown in Figure 11 , a control method of a magneto-rheological fluid self-adaptive anti-icing wind turbine blade, taking the magneto-rheological fluid self-adaptive anti-icing wind turbine blade in example one as an example, includes the following steps:

[0066] Step one, pre-material: add 60% volume fraction of carbonyl iron powder (particle size 5 μm), 30% dimethyl silicone oil (viscosity 100 cSt) and 10% fumed silica into a vacuum stirrer, mix for 30 min at a speed of 2000 rpm to obtain MRF, the zero-field viscosity of which is 1.2 Pa・s, and the shear yield strength under a magnetic field of 0.5 T is > 50 kPa;

[0067] Step two, process the blade: during the molding of the blade composite material, a 2mm cavity area 6 is reserved in the 0%~30% chord length area of the leading edge of the shell 1 for integrating the MRF (magneto-rheological fluid) interlayer 7, and the cavity area 6 is filled with MRF by injection to form the MRF interlayer 7;

[0068] Step three, blade molding: after injecting the MRF prepared in step one into the reserved cavity area 6, cover a 0.1mm thick PET / ITO flexible conductive film, bond it with the shell 1 through a hot pressing process under the condition of a set temperature of 80℃ and a set pressure of 0.5MPa to form the skin 5, and then spray primer and topcoat on the remaining areas of the blade surface in turn to ensure that the bonding accuracy of the MRF interlayer 7 and the skin 5 is <0.1mm;

[0069] Among them, the primer can be selected from ultraviolet light-cured paint, and the topcoat can be selected from epoxy resin and polyurethane paint;

[0070] Step four, arrange the magnetic field: embed a set of electromagnets 8 with size of 5mm x 5mm x 2mm every 5cm along the blade span, the core uses soft magnetic alloy Fe73.5Cu1Nb3Si13.5B9, the coverage area of adjacent electromagnets magnetic field overlaps more than 20% to ensure uniformity, and the electromagnets 8 are connected to the PLC controller 9 located at the blade root through shielded wire, install polymer capacitive humidity sensor 10 (accuracy ± 2% RH) and PT100 type temperature sensor 11 (accuracy ± 0.5℃) on the leading edge and pressure surface of the blade, the sensor probe maintains a 10mm spacing with the MRF interlayer 7 to avoid magnetic field interference;

[0071] Step five: connect the two sensor signals to the PLC controller 9 located at the blade root, the electromagnet 8 drive circuit integrates a pulse width modulation (PWM) module, supports 0T-0.8T magnetic field strength adjustment, and writes the control logic: when the dew point temperature <0℃ and the humidity >80%, the PLC controller 9 outputs a 10kHz pulse signal (duty ratio 1:4) to drive the electromagnet 8, maintaining a 0.5T magnetic field strength; when the dew point temperature ≥0℃, the magnetic field is automatically cut off, and the MRF interlayer 7 returns to liquid state;

[0072] Step six: install the blade specimen in a -10℃ low temperature wind tunnel, control the wind speed to 10m / s and the humidity to 90% to simulate icing conditions, start the electromagnet, use a high-speed camera with a frame rate of 1000fps to record the MRF solidification process, and verify that it forms a jagged surface with a roughness Ra=5μm-10μm within 20ms; monitor the liquid recovery of the MRF interlayer 7 within 50ms after the magnetic field is removed, continuously spray for 30min when the magnetic field is not activated, and the blade icing thickness can reach 2.5mm; after activating the magnetic field, the ice layer is fragmented, with a maximum thickness of <0.5mm, and the ice layer adhesion measured by a dynamometer is reduced from 18kPa to below 3kPa;

[0073] Step seven: use a pulse power supply mode with a duty ratio of 1:4, use a power meter to measure the average power consumption of the system as 4.8W / m², the energy consumption is 0.12kW・h for 24h continuous operation, conduct 1000 times of magnetic field activation-close cycle test, verify that the MRF solidification-liquid state conversion efficiency has no obvious attenuation, at the same time test the adhesion of the blade surface conductive film and the substrate >5MPa, to ensure long-term operation stability.

[0074] In summary, the magnetorheological fluid prepared by using carbonyl iron powder and silicone oil-based carrier liquid forms a jagged rough surface within 20ms under a 0.5T magnetic field, the roughness Ra is 5-10μm, the adhesion of ice layer is reduced from 18kPa of traditional coating to below 3kPa, the ice thickness on the blade is inhibited from 2.5mm to below 0.5mm under the working conditions of-10℃ and 90% humidity, effectively destroying the continuity of ice layer; at the same time, the PLC controller 9 adopts pulse power supply mode with a duty cycle of 1:4, the average power consumption is only 4.8W / m², which is 72% lower than the traditional electric heating, the energy consumption is only 0.12kW·h for 24h continuous operation, and through the double-parameter trigger mechanism of temperature signal threshold and humidity signal threshold, invalid energy consumption is avoided, which is 70% lower than the traditional fixed threshold control, the array of micro electromagnetic iron 8 realizes the uniformity deviation of magnetic field <5%, ensures the consistency of MRF solidification form, 1000 cycle tests verify that the rheological stability has no attenuation, the adhesion between the conductive film and the blade shell 1 is >5MPa, which meets the long-term fatigue resistance requirement.

[0075] In addition, the response time of the PLC controller 9 is <20ms, which can respond to the rapid icing scene in real time, the MRF returns to liquid state under no ice condition, the roughness Ra of the blade surface is <1μm, the aerodynamic efficiency is maintained, and it can work stably under the temperature range of-30℃-0℃ and the humidity environment of 60%-100%, which reduces the icing downtime of wind turbines by more than 60% when running in cold and humid areas, saves more than 200,000 yuan of operation and maintenance cost per year for a single unit, and significantly improves the power supply reliability and economic efficiency of the wind power system.

[0076] The above only describes optional embodiments of the present application, and it should be pointed out that for ordinary skilled persons in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application. The structures, devices and operation methods not specifically described and explained in the present application, such as without special description and limitation, are implemented according to the conventional means in the art.

Claims

1. A magnetorheological fluid self-adaptive anti-icing wind turbine blade comprising a shell (1), characterized in that: The shell (1) is internally provided with a girder (2), a web plate (3) connected with the girder (2), a core material (4) spaced from the web plate (3), and an electromagnet (8) connected with the web plate (3); The front edge region of the shell (1) is provided with a cavity area (6), the cavity area (6) is provided with a MRF interlayer (7) and a skin (5) which are attached to each other, and the root of the shell (1) is provided with a PLC controller (9) for controlling the electromagnet (8); When the electromagnet (8) is started, the MRF interlayer (7) is solidified by the magnetic field of the electromagnet (8) to extrude the external ice layer, and vice versa, the electromagnet (8) is dormant, the MRF interlayer (7) returns to liquid state, thereby maintaining the aerodynamic shape of the blade after deicing; The front edge region of the shell (1) is provided with a humidity sensor (10) and a temperature sensor (11) which are installed at a position different from the cavity area (6), and the humidity sensor (10) and the temperature sensor (11) are connected to the PLC controller (9); The humidity sensor (10) and the temperature sensor (11) monitor the temperature and humidity signals outside the blade and send them to the PLC controller (9) for controlling the working state of the electromagnet (8); The girder (2) is internally provided with an alloy framework (12) in a hollow shape along the axial direction of the shell (1), the alloy framework (12) is provided with an insulating mounting frame (13) for bearing the electromagnet (8), and the bottom of the insulating mounting frame (13) is fixedly provided with a pawl (14) in contact with the bottom wall of the alloy framework (12); The top of the insulating mounting frame (13) is provided with a moisture absorbing cotton strip (15) surrounding the electromagnet (8) and a water absorbing resin bead (16) wrapped inside the moisture absorbing cotton strip (15); When the shell (1) is damp, the moisture absorbing cotton strip (15) and the water absorbing resin bead (16) absorb moisture to separate the moisture from the electromagnet (8); The shell (1) is further provided with a male plug (17) and a female socket (18) which are inserted into each other, the female socket (18) is embedded in the alloy framework (12), and the male plug (17) is connected with the moisture absorbing cotton strip (15); When the male plug (17) and the female socket (18) are inserted, the humidity sensor (10) and the temperature sensor (11) are powered on; When the moisture absorbing cotton strip (15) is damp, it is disconnected from the male plug (17), so that the male plug (17) and the female socket (18) are separated, so that the humidity sensor (10) and the temperature sensor (11) are powered off and offline, indicating a fault signal; The male plug (17) is externally provided with a memory spring member (19) connected with the alloy framework (12), the moisture absorbing cotton strip (15) is externally provided with a water-soluble paper (20), and the male plug (17) is connected with the moisture absorbing cotton strip (15) through the water-soluble paper (20); When the moisture absorbing cotton strip (15) is wet, the water-soluble paper (20) contacts water to dissolve, so that the male plug (17) is unlocked, and the male plug (17) is separated from the female socket (18) under the elastic potential energy of the memory spring (19).

2. A magnetorheological fluid self-adapting anti-icing wind turbine blade according to claim 1, characterized in that: The moisture absorbing cotton strip (15) and the water-soluble paper (20) are provided with an open limiting ring (21) therebetween, the bottom of the limiting ring (21) is fixed to the top surface of the insulating mounting frame (13), and the outer side of the insulating mounting frame (13) is fixed with a positioning node (22) which is inserted into the opening of the limiting ring (21).

3. A control method of a magnetorheological fluid adaptive de-icing wind turbine blade, applied to the magnetorheological fluid adaptive de-icing wind turbine blade of any one of claims 1-2, characterized in that, The method comprises the following steps: Step one, pre-material: add carbonyl iron powder, dimethyl silicone oil and fumed silica into a vacuum stirrer to mix and prepare MRF, which is reserved for later use; Step two, processing blade: in the blade composite material forming stage, a cavity area (6) is reserved in the leading edge area of the shell (1), the cavity area (6) is filled with MRF by injection to form an MRF interlayer (7); Step three, blade forming: after the cavity area (6) is injected, a PET / ITO flexible conductive film is covered, the PET / ITO flexible conductive film is bonded with the shell (1) through a hot pressing process to form a skin (5), and then the remaining area of the blade surface is sprayed with primer and topcoat in sequence; Step four, arranging magnetic field: embedding electromagnets (8) along the blade span direction, the electromagnets (8) are connected to the PLC controller (9) located at the blade root through shielded wires, a humidity sensor (10) and a temperature sensor (11) are installed at the leading edge and pressure surface of the blade, the humidity sensor (10) and the temperature sensor (11) are kept away from the MRF interlayer (7) to avoid magnetic field interference; Step five, regulating and controlling deicing: the PLC controller (9) prewrites control logic, when the temperature signal and the humidity signal exceed the threshold value, the PLC controller (9) drives the electromagnets (8) to apply a magnetic field to the MRF interlayer (7) to make the MRF interlayer (7) deform to break the ice layer; when the temperature signal does not exceed the threshold value, the PLC controller (9) automatically cuts off the magnetic field to make the MRF interlayer (7) restore to liquid state; Step six, testing blade: installing the blade test piece in the wind tunnel to simulate icing conditions, starting the electromagnets (8), using a camera to record the solidification process of the MRF interlayer (7), verifying the surface change of the MRF interlayer (7), and measuring the ice layer adhesion change through a tension meter; monitoring the liquid state recovery of the MRF interlayer (7) after removing the magnetic field; Step seven, stability detection: the PLC controller (9) is powered by a pulse mode with a duty ratio of 1:4, the average power consumption of the system is monitored by a power meter, the energy consumption of continuous operation for 24 hours is monitored, and a 1000-cycle magnetic field activation-cutoff cycle test is conducted to verify the change of the MRF solidification-liquid state conversion efficiency, and the change of the adhesion between the skin (5) and the shell (1) is tested.

4. A control method of a magnetorheological fluid self-adaptive anti-icing wind turbine blade according to claim 3, characterized in that: The carbonyl iron powder, dimethyl silicone oil and fumed silica in step one are mixed by stirring at a volume fraction ratio of 60%:30%:10%, the stirring is mixed at a speed of 2000 rpm for 30 min to prepare MRF, at this time, the zero field viscosity of MRF is 1.2 Pa·s, and the shear yield strength of MRF under a magnetic field of 0.5 T is >50 kPa.

5. A control method of a magnetorheological fluid self-adaptive anti-icing wind turbine blade according to claim 3, characterized in that: When the temperature signal is <0℃ and the humidity signal is >80%, the PLC controller (9) outputs a 10 kHz pulse signal to drive the electromagnet (8) to maintain a magnetic field strength of 0.5 T; When the temperature signal is ≥0℃, the PLC controller (9) automatically cuts off the magnetic field to restore the MRF interlayer (7) to a liquid state.

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