Wind turbine blade de-icing system and phase change microcapsule coating spraying process

Abstract

This invention provides a wind turbine blade de-icing system and a phase change microcapsule coating spraying process, relating to the field of wind power equipment protection technology. The de-icing system includes a heating module, a spiral guide rib, a phase change microcapsule coating, and a control module. The heating module includes a heating element and a fan connected to the heating element. The spiral guide rib forms a swirling airflow channel, causing the hot air generated by the heating module to form a swirling airflow. The phase change microcapsule coating is applied to at least the inner wall of the blade. The control module is communicatively connected to the heating element and the fan, and is configured to adjust the fan speed and the heating power of the heating element based on at least the state of the phase change microcapsule coating. This de-icing system improves heat transfer efficiency, allowing hot air to effectively cover all areas of the blade, extending the residence time of hot air in the blade's inner cavity, and improving hot air utilization. The phase change microcapsule coating and the swirling airflow work together to effectively raise the blade wall temperature rapidly and uniformly, improving de-icing efficiency.

Description

Technical Field

[0001] This invention relates to the field of wind power equipment protection technology, and in particular to a wind turbine blade de-icing system and a phase change microcapsule coating spraying process. Background Technology

[0002] When wind turbines operate in cold and humid environments, blade icing significantly reduces their aerodynamic performance and power generation efficiency, and can even pose safety hazards. Hot air de-icing, as an effective active de-icing method, has been widely researched and applied.

[0003] Currently, hot air is typically delivered through straight channels located inside the blades. However, this method presents at least the following technical problems: (1) The hot air flows in a straight line and has a short contact time with the inner wall of the blade, only 0.5-1 seconds, resulting in a large amount of heat not being fully utilized, with a heat loss rate as high as 30%-40%. (2) The hot air flows in a laminar flow state and has a low heat transfer coefficient with the wall, which makes it difficult for heat to spread quickly and evenly to the icing area on the outer surface of the blades, resulting in a local temperature deviation of more than 10°C.

[0004] (3) Hot air can easily form vortex dead zones in the blade cavity, resulting in insufficient heat flow coverage in key icing areas such as the blade tip and leading edge, thus affecting the de-icing effect.

[0005] In summary, the straight-channel hot air de-icing method inside the blade has technical problems such as low convective heat transfer coefficient between hot air and blade wall, short contact time between hot air and blade wall, low heat utilization rate, and difficulty in uniformly transferring heat to blade wall, resulting in de-icing blind zones.

[0006] Therefore, there is an urgent need for a de-icing system that can effectively improve the utilization rate and heat transfer efficiency of hot air, and enable hot air to effectively cover all areas of the blades. Summary of the Invention

[0007] The existing straight-channel hot air de-icing method inside the blade suffers from problems such as low convective heat transfer coefficient between hot air and the blade wall, short contact time between hot air and the blade wall, low heat utilization rate, and difficulty in uniformly transferring heat to the blade wall, resulting in de-icing blind zones. The purpose of this invention is to provide a wind turbine blade de-icing system that can effectively improve hot air utilization and heat transfer efficiency, and ensure that hot air effectively covers all areas of the blade.

[0008] A wind turbine blade de-icing system includes: A heating module is located at one end of the blade cavity near the blade root, and includes a heating element and a fan connected to the heating element, for heating the airflow to form a hot airflow. Spiral guide ribs are used to form a swirling air duct, so that the hot air generated by the heating module forms a swirling airflow. A phase change microcapsule coating is applied at least to the inner wall of the blade to form a heat buffer layer; A control module, communicatively connected to the heating element and the fan, is configured to adjust the fan speed and the heating power of the heating element based at least on the state of the phase change microcapsule coating.

[0009] Optionally, the pitch of the spiral guide rib is 200-300mm, the spiral angle is 30-45°, and the height is 1-2mm.

[0010] Optionally, the outlet end of the swirl duct is formed as a gradually expanding structure, and the expansion angle of the gradually expanding structure is 15°; And / or, the outlet end of the swirl duct is provided with multiple circumferentially distributed guide ports; And / or, the blade cavity is provided with a web, and the web is coated with heat-insulating aerosol.

[0011] Optionally, the phase change microcapsule coating includes a phase change core material and a microcapsule wall material that encapsulates the phase change core material; The phase change core material is a n-eicosane-docosahexanes composite alkane, and its mass ratio is 3:2; And / or, the microcapsule wall material is a polyurea-silica composite wall material.

[0012] Optionally, the phase change microcapsule coating further includes functional additives, which, by weight percentage, comprise: 2%-3% γ-aminopropyltriethoxysilane; 1%-2% polycarboxylate dispersant; 1%-2% ethylene glycol butyl ether; 0.5%-1% of benzotriazole UV absorbers.

[0013] Optionally, the control module includes a PID control unit with the phase change microcapsule coating temperature as the controlled variable, the PID control unit being configured to: When the temperature of the phase change microcapsule coating is lower than the lower limit of the preset phase change temperature range, the fan speed and the heating power of the heating element are increased. When the temperature of the phase change microcapsule coating reaches or exceeds the upper limit of the preset phase change temperature range, the fan speed and the heating power of the heating element are reduced.

[0014] Optionally, the control module is further configured to predict the icing trend of the blades based on environmental parameters using a pre-trained icing prediction model, and control the opening and closing of the heating module accordingly.

[0015] Optionally, the control module is specifically configured as follows: When the predicted ice thickness is ≥1mm, the heating element and the fan are activated; when the predicted ice thickness is ≤0.3mm, the heating element and the fan are deactivated.

[0016] On the other hand, the present invention provides a phase change microcapsule coating spraying process, applied to the manufacture of the wind turbine blade de-icing system described in any of the above embodiments, comprising the following steps: Substrate pretreatment: Plasma activation treatment is performed on the surface of the substrate in the inner cavity of the blade and the outer wall of the swirl duct; Spraying: High-pressure airless spraying equipment is used to spray the phase change microcapsule coating onto the pretreated substrate surface in multiple layers, with a preset time interval between each layer to form a phase change microcapsule coating of a preset thickness. Curing: Curing the phase change microcapsule coating formed by spraying.

[0017] Optionally, in the substrate pretreatment step, an atmospheric pressure plasma spray gun is used for treatment. The atmospheric pressure plasma spray gun has a power of 3kW, a moving speed of 5m / min, and a distance of 10-15 cm between the spray gun head and the substrate surface. And / or, in the spraying step, the high-pressure airless spraying equipment is equipped with a flexible extension spray gun, the flexible extension spray gun has a moving speed of 3-5 m / min, a spraying distance of 15-20 cm, and a spraying angle perpendicular to or at 45° to the spraying surface. And / or, in the spraying step, the inner cavity area of ​​the blade corresponding to the outlet of the swirl duct and the inner cavity area of ​​the blade leading edge are subjected to enhanced spraying.

[0018] Compared with the prior art, the wind turbine blade de-icing system provided in this embodiment of the invention has at least the following technical effects: The wind turbine blade de-icing system includes a heating module, a spiral guide rib, a phase change microcapsule coating, and a control module. The heating module is located at the end of the blade's inner cavity near the blade root. The heating module includes a heating element and a fan connected to the heating element, and is used to heat the airflow to form a hot airflow. The spiral guide rib forms a swirling airflow channel, causing the hot air generated by the heating module to form a swirling airflow. The phase change microcapsule coating is applied at least to the inner wall of the blade to form a heat buffer layer. The control module is communicatively connected to the heating element and the fan, and is configured to adjust the fan speed and the heating power of the heating element based at least on the state of the phase change microcapsule coating. This wind turbine blade de-icing system utilizes a swirling airflow channel to guide the hot air into a forced swirling flow, improving heat transfer efficiency, ensuring that the hot air effectively covers all areas of the blade, and extending the residence time of the hot air within the blade's inner cavity, reducing heat loss and improving hot air utilization. In addition, the phase change microcapsule coating undergoes a solid-liquid phase change, which can efficiently absorb and store latent heat, forming a dual and synergistic thermal effect of "forced convection of swirling hot air + phase change microcapsule coating phase change heat storage and slow release". This effectively increases the blade wall temperature rapidly and uniformly, thereby improving de-icing efficiency.

[0019] Phase change microcapsule coating spraying technology is applied to the manufacturing of wind turbine blade de-icing systems. By plasma-activating the substrate surface of the blade's inner cavity and the outer wall of the swirl duct, a high-pressure airless spraying device is used to spray the phase change microcapsule coating onto the pre-treated substrate surface in multiple coats, with a preset time interval between each coat to form a phase change microcapsule coating of a predetermined thickness. The sprayed phase change microcapsule coating is then cured, enhancing the interfacial adhesion between the coating and the substrate, resulting in excellent weather resistance. This process is suitable for the complex internal structure of wind turbine blades and is applicable to harsh environments such as cold regions and high altitudes. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of a wind turbine blade de-icing system in one embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0024] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0025] The straight-channel hot air de-icing method inside the blade has technical problems such as low convective heat transfer coefficient between hot air and blade wall, short contact time between hot air and blade wall, low heat utilization rate, and difficulty in uniformly transferring heat to blade wall, resulting in the formation of de-icing blind zones.

[0026] For the above technical issues, please refer to the appendix. Figure 1 As shown, an embodiment of the present invention provides a wind turbine blade de-icing system, including a heating module, a spiral guide rib 20, a phase change microcapsule coating 30, and a control module 40. The heating module is disposed at one end of the blade inner cavity near the blade root. The heating module includes a heating element 11 and a fan 12 connected to the heating element 11. The heating module is used to heat the airflow to form a hot airflow. The spiral guide rib 20 is used to form a swirling air duct 50, so that the hot air generated by the heating module forms a swirling airflow. The inlet end of the swirling air duct 50 is connected to the heating element 11 through a ventilation pipe 60. The phase change microcapsule coating 30 is coated at least on the inner wall of the blade to form a heat buffer layer. The control module 40 is communicatively connected to the heating element 11 and the fan 12 and is configured to adjust the rotation speed of the fan 12 and the heating power of the heating element 11 at least according to the state of the phase change microcapsule coating 30.

[0027] It should be further explained that the blade's inner cavity is equipped with a web 70, forming a tapering airflow channel 80 between the web 70 and the blade's inner cavity wall. The tapering airflow channel 80 may contain, but is not limited to, 3 to 4 helical guide ribs. To accommodate the aerodynamic shape of the blade, where the cross-sectional area gradually decreases from the root to the tip, and to maintain a stable airflow velocity, the airflow channel diameter adopts a non-linear gradient design, smoothly tapering from the root to the tip. Its profile curve follows the functional relationship: D(x) = D root -k × x n Among them, D root The root diameter is approximately 15 mm, x represents the axial position, and k and n are coefficients optimized based on the aerodynamic shape of the specific blade model. This design is based on the principle of flow conservation in fluid mechanics (Q = A1 × V1 = A2 × V2), aiming to ensure stable airflow velocity. Simulation analysis and experimental verification show that when a uniform velocity gradient of 0.12 mm / m is used, the velocity of the hot air within the entire duct can be stabilized at 8-12 m / s, effectively avoiding eddies caused by sudden velocity changes. In contrast, if the diameter variation gradient is improperly designed (e.g., greater than 0.2 mm / m), the wind speed in the blade tip region will be too high (exceeding 15 m / s), causing a surge in duct friction resistance and increasing system energy consumption by more than 12%.

[0028] This embodiment addresses the problems of uneven heat distribution and low thermal efficiency in traditional direct-blowing hot air de-icing systems. It utilizes a swirl duct 50 to guide the hot air into a forced swirling flow, increasing the contact area between the hot air and the inner wall of the blades. This improves the heat transfer coefficient by 30%-40% and effectively extends the residence time of the hot air to 2-3 seconds, reducing heat loss and improving de-icing efficiency. Specifically, the core theoretical basis for swirl-enhanced heat transfer is the correlation model between the swirl number and the Nusselt number. S w The calculation formula is: S w = (π·D·tanα) / (P·n·h), in, D The diameter of the air duct. α The helix angle, P For pitch, n The number of spiral guide ribs, h This refers to the height of the spiral guide ribs. Numerical simulations have verified that when the swirl number... S w When the Nusselt number is in the optimization range of 0.6-0.8, the hot air can form a strong swirling state without any vortex dead zones. No Compared to conventional straight channels, it can improve heat transfer efficiency by 42%-55%, corresponding to an increase of approximately 30%-40% in the heat transfer coefficient in actual engineering projects. Based on this theoretical model and considering the fluid resistance constraints of a conventional blade length (e.g., 58 meters), this embodiment, through optimized calculations, determined a set of preferred parameters for the swirl duct: the helical guide ribs adopt a constant pitch helical design with a pitch of 200-300 mm (the pitch can be adjusted adaptively according to the blade cross-sectional dimensions), a helix angle of 30-45°, a height of 1-2 mm, and a thickness of 1 mm. Preferably, the pitch is 250 mm, the helix angle is 35°, and the height of the helical guide ribs is 1.5 mm. This parameter combination ensures that the airflow maintains a swirl number throughout the entire duct length. S w It stabilized at 0.72±0.03, achieving a balance between heat transfer efficiency and wind resistance.

[0029] It should be further explained that this embodiment introduces a phase change microcapsule coating. This coating undergoes a solid-liquid phase change within the hot air temperature range, absorbing and storing a large amount of latent heat to form a heat buffer layer. This layer, in conjunction with the swirling hot air, homogenizes the blade wall temperature and enhances the heat transfer efficiency between the ice layer and the blades. The phase change temperature of the phase change microcapsule coating matches the hot air temperature. The synergistic working mechanism of the swirling hot air and the phase change microcapsule coating 30 is based on the following heat balance equation: Q heat =Q phase +Q trans ,in, Q heat The heat input for hot air Q phase The latent heat absorbed during the phase change process of the phase change microcapsule coating. Q trans This is for transferring heat outwards through the blade wall (used for melting ice).

[0030] In summary, the wind turbine blade de-icing system of this embodiment includes a heating module, a spiral guide rib 20, a phase change microcapsule coating 30, and a control module 40. The heating module is located at one end of the blade's inner cavity near the blade root. The heating module includes a heating element 11 and a fan 12 connected to the heating element 11. The heating module is used to heat the airflow to form a hot airflow. The spiral guide rib 20 is used to form a swirling air duct 50, so that the hot air generated by the heating module forms a swirling airflow. The phase change microcapsule coating 30 is coated at least on the inner wall of the blade to form a heat buffer layer. The control module 40 is communicatively connected to the heating element 11 and the fan 12 and is configured to adjust the speed of the fan 12 and the heating power of the heating element 11 at least according to the state of the phase change microcapsule coating 30. This wind turbine blade de-icing system uses the swirling air duct 50 to guide the hot air to form a forced swirling flow, which improves the heat transfer efficiency, allows the hot air to effectively cover all areas of the blade, and prolongs the residence time of the hot air in the inner cavity of the blade, reducing heat loss and improving the utilization rate of the hot air. In addition, the phase change microcapsule coating 30 undergoes a solid-liquid phase change, which can efficiently absorb and store latent heat, forming a dual and synergistic thermal effect of "forced convection of swirling hot air + phase change microcapsule coating phase change heat storage and slow release". This effectively increases the blade wall temperature rapidly and uniformly, thereby improving the de-icing efficiency.

[0031] In some optional embodiments, the web 70 is coated with an insulating aerosol to effectively reduce heat absorption by the web 70, thereby providing better heat storage enhancement for de-icing. The thickness of the insulating aerosol can be set to 50-100 μm.

[0032] In some optional embodiments, the outlet end of the swirl duct is formed as a gradually expanding structure with an expansion angle of 15°. This design is based on a diffuser flow loss model. Calculation and test data show that at a 15° expansion angle, the local drag coefficient ξ ≤ 0.15, significantly lower than the drag coefficient (ξ = 0.32) when using a 20° expansion angle. This structure can efficiently convert the kinetic energy of the airflow into static pressure energy.

[0033] In some optional embodiments, the outlet end of the swirl duct is provided with multiple circumferentially distributed guide ports. Specifically, the outlet end of the swirl duct has three circumferentially evenly distributed guide ports with a circumferential angle of 120°, oriented towards the most sensitive areas prone to icing, such as the leading edge and back of the blade. This allows the swirling hot air to cover approximately 95% of the leading edge area of ​​the blade, improving the de-icing effect. In contrast, conventional straight-tube outlets typically only achieve about 60% hot air coverage. Therefore, this embodiment significantly improves the hot air coverage area by optimizing the layout of the guide ports, ensuring that the hot air can be effectively distributed to the critical areas of the blade, thereby enhancing the blade's de-icing capability.

[0034] In some alternative embodiments, the blades and webs are made of epoxy resin composite material, which is resistant to high temperatures ≥120°C and pressure ≥0.3MPa.

[0035] In some alternative embodiments, the phase change microcapsule coating comprises, by weight percentage, 40%-50% of a phase change core material, 20%-25% of a microcapsule wall material for encapsulating the phase change core material, 20%-25% of a dispersion medium, and 5%-10% of functional additives.

[0036] For operating conditions with hot air temperatures of 55-75℃, differential scanning calorimetry (DSC) tests revealed that when n-eicosane (phase change temperature 36.8℃) and docosane (phase change temperature 44.2℃) are compounded at a mass ratio of 3:2, the phase change temperature can be broadened to 60-65℃ by utilizing the eutectic point shift effect, with a phase change enthalpy ≥180 J / g. This allows the compound to absorb 60%-70% of the heat input from the hot air, thus forming an effective heat buffer layer. It is important to note that if the mass ratio deviates from 3:2, for example, to 2:3, the phase change temperature will decrease to 52-58℃. This will lead to a decrease in the matching degree with the hot air temperature, resulting in a reduction of the heat storage capacity of the phase change microcapsule coating by more than 15%, ultimately affecting the uniformity of the blade surface temperature.

[0037] Compared to using n-octadecane (phase change temperature of 28°C, unsuitable for hot air temperatures of 55-75°C) and paraffin (phase change enthalpy of only 150 J / g), the n-eicosane-docosahexanes composite alkane, at a mass ratio of 3:2, achieves a 90% overlap between its phase change temperature range and the hot air temperature, thus improving the matching degree. Simultaneously, the phase change enthalpy is increased by 20%, and no crystallization or stratification occurs at low temperatures (-40°C). Therefore, in some optional embodiments, the preferred phase change core material is the n-eicosane-docosahexanes composite alkane, with a mass ratio of 3:2.

[0038] In some optional embodiments, the microcapsule wall material is a polyurea-silica composite wall material. Specifically, this microcapsule wall material is prepared by interfacial polymerization, with a wall thickness of 1-3 μm and a porosity of ≤2%, effectively preventing leakage of the phase change core material while improving thermal conductivity. Compared to single polyurea wall materials (thermal conductivity of only 0.2 W / (m·K)), the polyurea-silica composite wall material, by adding 5%-8% nano-silica to polyurea, utilizes the "phonon conduction enhancement effect" to increase the thermal conductivity of the wall material to 0.5 W / (m·K). This improvement effectively solves the shortcomings of traditional phase change microcapsules in terms of "easy heat storage and difficult heat release". It is worth noting that if the silica content exceeds 10%, it will lead to increased brittleness of the wall material, thereby reducing its resistance to thermal cycling from 500 cycles to less than 300 cycles. Therefore, maintaining an appropriate silica content is an important factor in ensuring the performance of the microcapsule wall material.

[0039] In some optional embodiments, the dispersion medium is deionized water and ethanol in a mass ratio of 4:1, which is used to improve the dispersion stability of microcapsules.

[0040] In some optional embodiments, the functional additives, by weight percentage, include 2%-3% coupling agent, 1%-2% dispersant, 1%-2% film-forming aid, and 0.5%-1% anti-aging agent. Specifically, the coupling agent is γ-aminopropyltriethoxysilane, which enhances the chemical bonding between the coating and the blade composite material and the duct material. One end (-OEt) of the coupling agent can undergo a condensation reaction with the hydroxyl groups on the substrate to form a Si-OC bond; while the other end (-NH2) reacts with the isocyanate groups (-NCO) in the polyurea wall material to form a urea bond. In this way, γ-aminopropyltriethoxysilane constructs a chemical bond bridge between the substrate, the coupling agent, and the coating, thereby effectively improving the adhesion and durability of the coating. The dispersant is a polycarboxylate dispersant, designed to prevent microcapsule aggregation; the film-forming aid is ethylene glycol butyl ether, which can improve the uniformity of the coating; and the anti-aging agent is a benzotriazole UV absorber, to ensure the durability of the coating for long-term outdoor use.

[0041] In one specific embodiment, the formulation of the phase change microcapsule coating comprises, by mass percentage: 40%-50% of n-eicosane-docosahexanes (mass ratio of 3:2), 20%-25% of polyurea-silica composite wall material (of which silica accounts for 5%-8% by mass), 20%-25% of dispersion medium (deionized water and ethanol in a mass ratio of 4:1), and 5%-10% of functional additives (including 2%-3% of γ-aminopropyltriethoxysilane, 1%-2% of polycarboxylate dispersant, 1%-2% of ethylene glycol butyl ether, and 0.5%-1% of benzotriazole UV absorber). The phase change microcapsule coating exhibits excellent performance, with an adhesion grade of ≥5B (ISO 2409), and can withstand 500 cycles of thermal cycling from -40℃ to 80℃ without cracking or peeling. The phase change enthalpy decay remains at ≤5%, and the high temperature resistance reaches ≥120℃, demonstrating its reliability and durability in practical applications.

[0042] In some optional embodiments, the control module includes a PID control unit with the phase change microcapsule coating temperature as the controlled variable. The PID control unit is configured to: increase the fan speed and heating power of the heating element when the phase change microcapsule coating temperature is below the lower limit of a preset phase change temperature range; and decrease the fan speed and heating power of the heating element when the phase change microcapsule coating temperature reaches or exceeds the upper limit of the preset phase change temperature range. The phase change microcapsule coating temperature is monitored in real time by a temperature sensor 90.

[0043] In one specific embodiment, the preset phase change temperature range of 60-65℃ for the phase change microcapsule coating temperature is used as the controlled variable. The PID control unit is specifically configured as follows: when the phase change microcapsule coating temperature is below 60℃ (not reaching the phase change temperature), the control module appropriately increases the hot air temperature by 5-10℃ and the wind speed by 1-2 m / s, aiming to accelerate the heat transfer efficiency of the swirling hot air and prompt the phase change microcapsule coating to quickly absorb heat and initiate the phase change process. When the phase change microcapsule coating temperature reaches or exceeds 65℃ (completing phase change heat storage), the hot air temperature is reduced by 3-5℃ and the wind speed by 0.5-1 m / s. At this time, the de-icing is mainly maintained by the slow release of the stored latent heat from the phase change microcapsule coating, supplemented by the residual heat from the swirling air, thereby significantly reducing active energy consumption.

[0044] It should be further explained that the PID control unit is an incremental PID controller, and its control output formula is: Thu (k) = Kp[Δe(k) - Δe(k-1)] + KiΔe(k) + Kd[Δe(k) - 2Δe(k-1) + Δe(k-2)], in Kp=2.5, Ki=0.8, Kd=0.3 It can control the fluctuation range of hot air temperature within ±2℃, thereby ensuring that the thermal stress borne by the blade composite material is below the safety threshold of 20MPa and ensuring the structural integrity of the blade.

[0045] In some optional embodiments, the control module 40 is further configured to predict the icing trend of the blades based on environmental parameters using a pre-trained icing prediction model, and control the activation and deactivation of the heating module accordingly. The icing prediction model receives input parameters including data from six dimensions: ambient temperature, humidity, wind speed, and blade vibration frequency. Trained with 1000 sets of measured data from cold regions, it can predict icing trends accurately and in advance, with an error of ≤ 0.1mm in predicting ice thickness. Compared to traditional triggering methods based on fixed thresholds (with an error typically of 0.5mm), this embodiment can start the system 2-3 minutes earlier, further reducing energy consumption (by approximately 8%).

[0046] In some optional embodiments, the control module is specifically configured to: start the heating element 11 and the fan 12 when the predicted ice thickness is ≥1mm; and turn off the heating element 11 and the fan 12 when the predicted ice thickness is ≤0.3mm.

[0047] The working process of the wind turbine blade de-icing system is as follows: Standby phase: The phase change microcapsule coating 30 is in a solid state at room temperature. The icing prediction model predicts the icing trend, and the system is on standby. Start-up phase: When the predicted ice thickness is ≥1mm, the control module 40 issues a command to start the heating element 11 and the fan 12; Active de-icing and synergistic heat storage stage: Hot air forms a stable vortex through the swirl duct 50 and passes at high speed over the surface of the phase change microcapsule coating 30. The phase change microcapsule coating 30 absorbs heat and begins to undergo a solid-liquid phase change, storing latent heat. Simultaneously, the swirling hot air continuously replenishes the phase change microcapsule coating 30 with heat and enhances its heat transfer to the blade wall, forming a dual, synergistic thermal effect of "forced convection of swirling hot air + slow release of phase change heat storage from the phase change microcapsule coating." During this stage, the blade wall temperature rises rapidly and uniformly, accelerating the melting of the ice layer. Final De-icing and Reset Phase: When the predicted ice thickness is ≤0.3mm, the control module 40 issues a command to shut down the heating element 11 and the fan 12. At this time, the phase change microcapsule coating continues to release its remaining stored heat to ensure complete removal of any remaining thin ice. Subsequently, the phase change microcapsule coating naturally cools and re-solidifies into a solid state, preparing for the next de-icing cycle.

[0048] The wind turbine blade de-icing system provided by this invention has at least the following advantages: (1) Improved de-icing efficiency: The vortex duct design enables hot air to form a highly efficient vortex, increasing the heat transfer coefficient by approximately 35%. When combined with the heat storage effect of the phase change microcapsule coating, the uniformity of blade wall temperature is improved by 50% (blade temperature deviation does not exceed 5℃), resulting in an overall de-icing time that is 30%-35% shorter than that of traditional systems. For 5mm ice layers, the de-icing time can be controlled within 12 minutes, improving de-icing efficiency. (2) Reduced energy consumption: The swirling flow prolongs the residence time of hot air in the blades, increasing the heat utilization rate to over 85%. Combined with the waste heat recovery function of the phase change microcapsule coating, the comprehensive energy consumption of a single de-icing cycle can be reduced to below 0.58 kWh, which is 18%-23% lower than the energy consumption of the original de-icing system. (3) Excellent durability and reliability: The phase change microcapsule coating has good uniformity and adhesion of 5B grade. It can withstand thermal cycling and vibration shock. Its service life can be synchronized with the blades and air ducts, reaching more than 20 years. (4) Wide range of applications: The vortex duct structure is flexible and adaptable to wind turbine blades of different lengths (30-80 meters) and different aerodynamic shapes, and can be stably applied to various harsh environments such as cold regions and high altitudes from -40℃ to 0℃.

[0049] On the other hand, blade coating technology mainly focuses on corrosion protection and wear resistance of the outer surface, while lacking coatings specifically designed to enhance heat storage and transfer in the inner cavity. Some phase change coating-related patents (such as CN202310256789.1) are mainly used in buildings or electronic equipment, and their phase change temperature, adhesion and weather resistance are difficult to meet the working environment requirements of wind turbine blades (-40℃ to 80℃, vibration load, long-term damp heat cycle).

[0050] Furthermore, existing technologies lack specialized spraying processes for the complex internal features of blades (such as multiple curved surfaces and narrow channels). Traditional spraying processes (such as air spraying and brushing) struggle to penetrate the narrow areas of the blade's internal cavity, easily leading to uneven coating thickness, missed areas, and insufficient adhesion between the coating and the blade composite material (epoxy resin). This results in the coating easily detaching under blade rotational vibration and thermal cycling, hindering long-term stable operation. Therefore, one embodiment of the present invention provides a phase change microcapsule coating spraying process, applied to the manufacture of the wind turbine blade de-icing system of any of the above embodiments, comprising the following steps: Substrate pretreatment: Plasma activation treatment is performed on the surface of the substrate in the inner cavity of the blade and the outer wall of the swirl duct; Spraying: High-pressure airless spraying equipment is used to spray the phase change microcapsule coating onto the pretreated substrate surface in multiple layers, with a preset time interval between each layer to form a phase change microcapsule coating of a preset thickness. Curing: Curing the phase change microcapsule coating formed by spraying.

[0051] In this embodiment, the phase change microcapsule coating spraying process is applied to the manufacturing of a wind turbine blade de-icing system. By plasma-activating the substrate surface of the blade's inner cavity and the outer wall of the swirl duct, a high-pressure airless spraying device is used to spray the phase change microcapsule coating onto the pretreated substrate surface in multiple passes, with a preset time interval between each pass to form a phase change microcapsule coating of a preset thickness. The sprayed phase change microcapsule coating is then cured, enhancing the interfacial adhesion between the phase change microcapsule coating and the substrate. This results in excellent weather resistance, adaptability to the complex internal structure of wind turbine blades, and suitability for harsh environments such as cold regions and high altitudes.

[0052] Specifically, the substrate pretreatment step includes the following steps: Cleaning: Use 0.6MPa high-pressure air to blow clean the inner cavity of the blades and the outer wall of the swirl duct, then wipe with anhydrous ethanol to remove oil stains, and let it air dry naturally at 25℃ for 30 minutes. Plasma activation: Atmospheric pressure plasma spray gun is used for treatment, which can be equipped with a flexible and extended nozzle. The power of the atmospheric pressure plasma spray gun is 3kW, the moving speed is 5m / min, and the distance between the spray gun nozzle and the substrate surface is 10-15cm. This introduces active groups such as hydroxyl and carboxyl groups into the inner wall of the blade cavity and the outer wall of the swirl channel, thereby increasing the surface energy. It should be further noted that the power is the key factor affecting the adhesion. Experiments show that when the power is below 2kW, the number of hydroxyl functional groups introduced into the substrate surface is insufficient (<0.8 mmol / m²), resulting in a coating adhesion of only 3B grade; while when the power is above 4kW, it will cause oxidative degradation of the epoxy resin substrate, reducing its mechanical properties by about 5%. Therefore, the preferred power is 3kW±0.5kW. Primer application and curing: Apply an epoxy primer with a solid content of 50% by low-pressure spraying, control the dry film thickness to 10-15μm, and cure at 80℃ for 60 minutes to form a transitional bonding layer.

[0053] Substrate pretreatment aims to enhance interfacial adhesion, enabling the phase change microcapsule coating to form a "physical bond + chemical bond" with the blade composite material, thereby improving the coating's adhesion stability under vibration and thermal cycling conditions. This process is primarily based on a triple mechanism of "active group grafting - chemical bonding - physical bond bonding." First, through 3kW plasma activation, the C / C bonds on the epoxy resin surface break, introducing hydroxyl (-OH) and carboxyl (-COOH) groups. Test results show that the surface energy increases from 42 mN / m to 65 mN / m, indicating enhanced surface activity. Next, one end (-OEt) of the coupling agent γ-aminopropyltriethoxysilane undergoes a condensation reaction with the hydroxyl groups of the substrate, forming a Si-OC bond; its other end (-NH2) reacts with the isocyanate groups (-NCO) of the polyurea wall material to generate urea bonds, thus constructing a chemical bond bridge between the substrate, coupling agent, and coating. Finally, the cured epoxy primer forms a micron-level rough surface (roughness Ra = 1.2-1.5 μm), forming good physical bond with subsequent coatings. This series of treatments works synergistically to improve adhesion from 3B to 5B in conventional spraying, significantly enhancing the stability of the coating.

[0054] Furthermore, in the spraying step, an electric high-pressure airless sprayer with a working pressure of 15-20 MPa is used, equipped with a flexible, extendable spray gun with a length of 2-3 meters and an adjustable nozzle angle (0-90°) to adapt to narrow internal areas, curved surfaces, and the outer walls of air ducts. Before use, the coating needs to be ultrasonically dispersed at 300W power for 30 minutes and filtered through a 200-mesh filter to remove agglomerated particles. During spraying, the flexible, extendable spray gun moves at a speed of 3-5 m / min, the spraying distance is 15-20 cm, and the spraying angle is perpendicular to or at 45° to the spraying surface. It is worth noting that at 25℃, the phase change microcapsule coating is sprayed in 2-3 coats onto the pretreated substrate surface, each coat forming a dry film thickness of 20-30 μm, with a 30-minute interval between coats, resulting in a final total dry film thickness of 50-100 μm. The spraying interval is set based on solvent evaporation-film crosslinking kinetics. A 30-minute spray interval can reduce the solvent residue of the previous coating to below 3%. If the spray interval is shorter than 20 minutes, solvent retention will cause the coating to blister; if the spray interval is longer than 40 minutes, the previous coating will be over-cured, causing the interlayer adhesion to drop from 5B to 4B.

[0055] In some optional embodiments, during the spraying step, critical areas with high heat loads, such as the inner cavity area of ​​the blades corresponding to the outlet of the swirl duct and the inner cavity area of ​​the blade leading edge, are subjected to enhanced spraying. Specifically, an additional enhanced spraying can be performed to make the thickness of this area reach 80-100μm.

[0056] In the curing process, a segmented curing process is adopted. Specifically, it is first surface-dried at room temperature of 25°C for 2 hours, and then cured at a constant temperature of 60°C for 2 hours to achieve complete drying, ensuring that the coating is fully bonded to the substrate and the outer wall of the air duct. After curing, the coating surface is lightly sanded with 1000-grit sandpaper to remove burrs, and finally cleaned with high-pressure air.

[0057] The following describes the specific embodiments of the present invention in detail with reference to a 2.5MW wind turbine blade (58m in length and approximately 12m³ in internal volume).

[0058] Swirl duct fabrication: An epoxy resin composite material is used to integrally form a tapered duct through molding. The tapered duct design features a diameter that gradually decreases from 15mm to 8mm from the root to the blade tip. Three spiral guide ribs are installed within the tapered duct, forming a swirling duct within each rib. The spiral guide ribs have a pitch of 250mm, a spiral angle of 35°, and a height of 1.5mm. The outlet end of the swirling duct adopts a gradually expanding structure design with an expansion angle of 15° and three circumferential guide ports with an included angle of 120°.

[0059] Preparation of Phase Change Microcapsule Coating: The coating formulation (by mass fraction) is as follows: 45% eicosane and docosane composite core material, 22% polyurea and silica composite wall material, 23% deionized water and ethanol (4:1) mixture, 2.5% γ-aminopropyltriethoxysilane, 1.5% polycarboxylate dispersant, 2% ethylene glycol butyl ether, and 0.5% benzotriazole UV absorber. The coating was prepared using interfacial polymerization to prepare microcapsules with a particle size controlled between 1-10 μm. Subsequently, the microcapsules were mixed with the dispersion medium and additives, uniformly stirred, ultrasonically dispersed, and filtered to obtain the final coating. Performance testing results showed that the phase change temperature was 62℃, the phase change enthalpy was 185 J / g, the adhesion reached grade 5B, no cracking occurred after 500 thermal cycles, and the surface hardness was ≥2H.

[0060] Spraying process implementation: Blow-dry the substrate (blade inner cavity and duct outer wall) with high-pressure air → Wipe the substrate with anhydrous ethanol → Activate the substrate with plasma (speed 5m / min, distance 12cm) → Spray epoxy primer (12μm thickness) → Cure at 80℃ for 60 minutes → Disperse the coating ultrasonically for 30 minutes → Filter → First spray (25μm thickness, 30-minute interval) → Second spray (30μm thickness, 30-minute interval) → Third spray (25μm thickness) → Apply an additional coat (30μm thickness) to the duct outlet and leading edge inner cavity area → Cure at room temperature for 2 hours to surface dry → Cure at 60℃ for 2 hours to fully dry → Lightly sand the surface with 1000-grit sandpaper → Blow-dry with high-pressure air.

[0061] Collaborative De-icing Operation Verification: De-icing verification was conducted under environmental conditions of -15℃, 85% relative humidity, and 5mm ice thickness, as follows: Four minutes after startup, the swirling hot air rapidly raised the coating temperature to 62℃, completing phase change heat storage, and the blade wall temperature uniformly rose to 58℃, causing the ice layer to melt rapidly; eleven minutes after startup, the ice layer thickness decreased to 0.2mm, the hot air system was shut off, and the coating began to slowly release heat; twelve minutes after startup, the ice layer was completely removed, with a single de-icing energy consumption of 0.56kWh. Comparative Test: Traditional straight-channel uncoated de-icing time was 22 minutes, with an energy consumption of 1.05kWh. In comparison, this embodiment improved de-icing efficiency by 45.5% and reduced energy consumption by 46.7%; traditional straight-channel coated de-icing time was 19 minutes, with an energy consumption of 0.75kWh. In comparison, this embodiment improved de-icing efficiency by 36.8% and reduced energy consumption by 25.3%.

[0062] Long-term stability verification: After 100 de-icing cycles, the coating showed no peeling or cracking, and its phase change enthalpy decayed by only 3.2%; the spiral duct showed no deformation or air leakage, and its structural performance was stable.

[0063] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A de-icing system for wind turbine blades, characterized in that, include: A heating module is located at one end of the blade cavity near the blade root, and includes a heating element and a fan connected to the heating element, for heating the airflow to form a hot airflow. Spiral guide ribs are used to form a swirling air duct, so that the hot air generated by the heating module forms a swirling airflow. A phase change microcapsule coating is applied at least to the inner wall of the blade to form a heat buffer layer; A control module, communicatively connected to the heating element and the fan, is configured to adjust the fan speed and the heating power of the heating element based at least on the state of the phase change microcapsule coating. The phase change microcapsule coating includes a phase change core material and a microcapsule wall material that encapsulates the phase change core material; The phase change core material is a n-eicosane-eicosane composite alkane, and its mass ratio is 3:2; The microcapsule wall material is a polyurea-silica composite wall material; The phase change microcapsule coating further includes functional additives, which, by mass percentage, comprise: 2%-3% γ-aminopropyltriethoxysilane; 1%-2% polycarboxylate dispersant; 1%-2% ethylene glycol butyl ether; 0.5%-1% of benzotriazole UV absorbers.

2. The wind turbine blade de-icing system according to claim 1, characterized in that, The spiral guide rib has a pitch of 200-300mm, a spiral angle of 30-45°, and a height of 1-2mm.

3. The wind turbine blade de-icing system according to claim 1, characterized in that, The outlet end of the vortex duct is formed into a gradually expanding structure, and the expansion angle of the gradually expanding structure is 15°. And / or, the outlet end of the swirl duct is provided with multiple circumferentially distributed guide ports; And / or, the blade cavity is provided with a web, and the web is coated with heat-insulating aerosol.

4. The wind turbine blade de-icing system according to claim 1, characterized in that, The control module includes a PID control unit with the phase change microcapsule coating temperature as the controlled variable, and the PID control unit is configured to: When the temperature of the phase change microcapsule coating is lower than the lower limit of the preset phase change temperature range, the fan speed and the heating power of the heating element are increased. When the temperature of the phase change microcapsule coating reaches or exceeds the upper limit of the preset phase change temperature range, the fan speed and the heating power of the heating element are reduced.

5. The wind turbine blade de-icing system according to claim 1, characterized in that, The control module is also configured to predict the icing trend of the blades based on environmental parameters using a pre-trained icing prediction model, and control the opening and closing of the heating module accordingly.

6. The wind turbine blade de-icing system according to claim 5, characterized in that, The control module is specifically configured as follows: When the predicted ice thickness is ≥1mm, the heating element and the fan are activated; when the predicted ice thickness is ≤0.3mm, the heating element and the fan are deactivated.

7. A phase change microcapsule coating spraying process, applied to the manufacture of the wind turbine blade de-icing system according to any one of claims 1 to 6, characterized in that, Includes the following steps: Substrate pretreatment: Plasma activation treatment is performed on the surface of the substrate in the inner cavity of the blade and the outer wall of the swirl duct; Spraying: High-pressure airless spraying equipment is used to spray the phase change microcapsule coating onto the pretreated substrate surface in multiple layers, with a preset time interval between each layer to form a phase change microcapsule coating of a preset thickness. Curing: Curing the phase change microcapsule coating formed by spraying.

8. The phase change microcapsule coating spraying process according to claim 7, characterized in that, In the substrate pretreatment step, an atmospheric pressure plasma spray gun is used for treatment. The atmospheric pressure plasma spray gun has a power of 3kW, a moving speed of 5m / min, and a distance of 10-15 cm between the spray gun head and the substrate surface. And / or, in the spraying step, the high-pressure airless spraying equipment is equipped with a flexible extension spray gun, the flexible extension spray gun has a moving speed of 3-5 m / min, a spraying distance of 15-20 cm, and a spraying angle perpendicular to or at 45° to the spraying surface. And / or, in the spraying step, the inner cavity area of ​​the blade corresponding to the outlet of the swirl duct and the inner cavity area of ​​the blade leading edge are subjected to enhanced spraying.

Images