Wind driven generator blade deicing system and phase change microcapsule coating spraying process

Abstract

The invention provides a wind driven generator blade deicing system and a phase change microcapsule coating spraying process, and relates to the technical field of wind power generation equipment protection, the deicing system comprises a heating module, a spiral flow guide rib, a phase change microcapsule coating and a control module; the heating module comprises a heating piece and a fan communicated with the heating piece; the spiral flow guide rib is used for forming a rotational flow air duct, so that hot air formed by heating of the heating module forms rotational flow air flow; the phase change microcapsule coating is at least coated on the wall surface of the inner cavity of the blade; the control module is in communication connection with the heating piece and the draught fan and is configured to adjust the rotating speed of the draught fan and the heating power of the heating piece at least according to the state of the phase change microcapsule coating. The deicing system improves the heat transfer efficiency, enables hot air to effectively cover all areas of the blade, prolongs the residence time of the hot air in the inner cavity of the blade, and improves the hot air utilization rate. And the phase change microcapsule coating and the rotational flow airflow have a synergistic thermal effect, so that the temperature of the wall surface of the blade is effectively, quickly and uniformly increased, and the deicing efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation equipment protection, and particularly relates to a wind turbine blade deicing system and a phase change microcapsule coating spraying process. BACKGROUND

[0002] When a wind turbine operates in a cold and humid environment, icing of the blade can significantly reduce its aerodynamic performance and power generation efficiency, and even cause safety hazards. Hot air deicing, as an effective active deicing method, is widely studied and applied.

[0003] Currently, hot air is usually transported through a straight channel arranged in the blade. However, this method at least has the following technical problems: (1) The hot air contacts the inner cavity wall of the blade in a straight flow manner for a short time, only 0.5-1 seconds, resulting in a large amount of heat not being fully utilized, and a heat loss rate as high as 30%-40%. (2) The flow state of the hot air is laminar flow, and the heat transfer coefficient with the wall is low, resulting in difficulty in quickly and uniformly spreading the heat to the icing area on the outer surface of the blade, and a local temperature deviation exceeding 10℃.

[0004] (3) The hot air can easily form vortex dead angles in the inner cavity of the blade, resulting in insufficient heat flow coverage of the key icing areas such as the blade tip and leading edge, thereby affecting the deicing effect.

[0005] In summary, the straight channel hot air deicing method in the blade has the technical problems of low convective heat transfer coefficient between the hot air and the blade wall, short contact time between the hot air and the blade wall, low heat utilization rate, and difficulty in uniformly transferring heat to the blade wall, resulting in the formation of deicing blind areas.

[0006] Therefore, there is an urgent need for a deicing system that can effectively improve the utilization rate and heat transfer efficiency of hot air, and effectively cover all areas of the blade with hot air. SUMMARY

[0007] In view of the technical problems of the straight channel hot air deicing method in the blade in the prior art, such as low convective heat transfer coefficient between the hot air and the blade wall, short contact time between the hot air and the blade wall, low heat utilization rate, and difficulty in uniformly transferring heat to the blade wall, resulting in the formation of deicing blind areas, the purpose of the present application is to provide a wind turbine blade deicing system that can effectively improve the utilization rate and heat transfer efficiency of hot air, and effectively cover all areas of the blade with hot air.

[0008] A wind turbine blade deicing system, comprising: A heating module arranged at one end of the inner cavity of the blade close to the blade root, comprising a heating element and a fan in communication with the heating element, for heating the airflow to form a hot air flow; Spiral guide vanes are arranged to form a spiral flow channel, so that the hot air heated by the heating module forms a spiral flow. A phase change microcapsule coating is coated on at least the inner wall of the blade to form a heat buffer layer. A control module is in communication with the heating element and the fan, and is configured to adjust the rotation speed of the fan and the heating power of the heating element according to at least the state of the phase change microcapsule coating.

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

[0010] Optionally, the outlet end of the spiral flow channel is formed in a diverging structure, and the expansion angle of the diverging structure is 15°. And / or, the outlet end of the spiral flow channel is provided with a plurality of circumferentially distributed guide openings. And / or, the inner cavity of the blade is provided with a web, and the web is coated with a heat-insulating aerosol.

[0011] Optionally, the phase change microcapsule coating comprises a phase change core material and a microcapsule wall material wrapping the phase change core material. The phase change core material is a n-eicosane-dodecane composite alkane, and the mass ratio is 3:2. And / or, the microcapsule wall material is a polyurea-silicon dioxide composite wall material.

[0012] Optionally, the phase change microcapsule coating further comprises a functional additive, and the functional additive comprises, by mass percentage: 2%-3% of γ-aminopropyl triethoxysilane; 1%-2% of polycarboxylate dispersant; 1%-2% of ethylene glycol butyl ether; 0.5%-1% of benzotriazole ultraviolet absorber.

[0013] Optionally, the control module comprises a PID adjustment unit with the temperature of the phase change microcapsule coating as the controlled quantity, and the PID adjustment unit is configured to: When the temperature of the phase change microcapsule coating is less than the lower limit of the preset phase change temperature range, increase the rotation speed of the fan and the heating power of the heating element; When the temperature of the phase change microcapsule coating reaches or is higher than the upper limit of the preset phase change temperature range, reduce the rotation speed of the fan and the heating power of the heating element.

[0014] Optionally, the control module is further configured to predict the blade icing trend based on environmental parameters through 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 to: When the predicted ice layer thickness is ≥1mm, the heating element and the fan are started; when the predicted ice layer thickness is ≤0.3mm, the heating element and the fan are turned off.

[0016] In another aspect, the present application provides a phase change microcapsule coating spraying process applied to the manufacture of the wind turbine blade deicing system according to any one of the above embodiments, comprising the following steps: Substrate pretreatment: plasma activation treatment is performed on the substrate surface of the blade inner cavity and the outer wall of the cyclone air duct; Spraying: using a high-pressure airless spraying device, the phase change microcapsule coating is sprayed on the pretreated substrate surface in multiple passes, and after each spraying, a preset time interval is set to form a phase change microcapsule coating with a preset thickness; Curing: the phase change microcapsule coating formed by spraying is cured.

[0017] Optionally, in the substrate pretreatment step, an atmospheric pressure plasma torch is used for treatment, the power of the atmospheric pressure plasma torch is 3kW, the moving speed is 5m / min, and the distance between the torch head and the substrate surface is 10-15 cm; And / or, in the spraying step, the high-pressure airless spraying device is equipped with a bendable extension spray gun, the moving speed of the bendable extension spray gun is 3-5 m / min, the spraying distance is 15-20 cm, and the spraying angle is perpendicular or 45° to the spraying surface; And / or, in the spraying step, the blade inner cavity area corresponding to the outlet of the cyclone air duct and the inner cavity area of the blade leading edge are intensively sprayed.

[0018] Compared with the prior art, the wind turbine blade deicing system provided by the embodiments of the present application at least has the following technical effects: The wind turbine blade deicing system comprises a heating module, a spiral guide vane, a phase change microcapsule coating and a control module; the heating module is arranged at one end of the blade cavity close to the blade root, and comprises a heating element and a fan in communication with the heating element; the heating module is used for heating air flow to form hot air flow; the spiral guide vane is used for forming a spiral flow air duct to make the hot air heated by the heating module form a spiral flow; the phase change microcapsule coating is coated on at least the inner wall of the blade cavity to form a heat buffer layer; and the control module is in communication connection with the heating element and the fan, and is configured to adjust the rotating speed of the fan and the heating power of the heating element according to at least the state of the phase change microcapsule coating. The wind turbine blade deicing system uses the spiral flow air duct to guide the hot air to form forced spiral flow, improves the heat transfer efficiency, makes the hot air effectively cover each area of the blade, prolongs the residence time of the hot air in the blade cavity, reduces heat loss, and improves the utilization rate of the hot air. In addition, the phase change microcapsule coating can efficiently absorb and store latent heat due to solid-liquid phase change, and forms a double and synergistic heat effect of "forced convection of spiral hot air + phase change microcapsule coating phase change heat storage and slow release", which effectively makes the blade wall surface temperature rapidly and uniformly rise, thereby improving the deicing efficiency.

[0019] The phase change microcapsule coating spraying process is applied to manufacture the wind turbine blade deicing system. The substrate surface of the blade cavity and the outer wall of the spiral flow air duct is subjected to plasma activation treatment, the phase change microcapsule coating is sprayed on the pretreated substrate surface in multiple passes by using a high-pressure airless spraying device, a preset time interval is set after each spraying pass to form a phase change microcapsule coating with a preset thickness, and the phase change microcapsule coating formed by spraying is subjected to solidification treatment to strengthen the interfacial adhesion of the phase change microcapsule coating and the substrate, and the phase change microcapsule coating has excellent weather resistance and is suitable for the complex inner cavity structure of the wind turbine blade and harsh environments such as cold regions and high altitudes. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0021] Figure 1 It is an embodiment of the wind turbine blade deicing system. DETAILED DESCRIPTION

[0022] In order for those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

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

[0024] It should be noted that the structure, proportion, size, etc. shown in the drawings of the present application are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the conditions that can be implemented by the present application, so they do not have technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0025] The straight channel hot air deicing method inside the blade has the technical problems of low convective heat transfer coefficient between hot air and blade wall surface, short contact time of hot air and blade wall surface, low heat utilization rate, and difficulty in uniform heat transfer to the blade wall surface, resulting in the formation of deicing blind area.

[0026] In view of the above technical problems, please refer to the accompanying Figure 1 An embodiment of the present application provides a wind turbine blade deicing system, which comprises a heating module, a spiral guide rib 20, a phase change microcapsule coating layer 30 and a control module 40. The heating module is arranged at one end of the blade cavity close to the blade root. The heating module comprises a heating element 11 and a fan 12 in communication with the heating element 11. The heating module is used to heat the airflow to form a hot air flow. The spiral guide rib 20 is used to form a spiral flow channel 50, so that the hot air heated by the heating module forms a spiral flow. The inlet end of the spiral flow channel 50 is connected to the heating element 11 through a ventilation pipe 60. The phase change microcapsule coating layer 30 is coated at least on the inner wall surface of the blade cavity, and is used to form a heat buffer layer. The control module 40 is in communication connection with the heating element 11 and the fan 12, and is configured to adjust the rotating speed of the fan 12 and the heating power of the heating element 11 according to at least the state of the phase change microcapsule coating layer 30.

[0027] It should be further explained that the inner cavity of the blade is provided with a web plate 70, and a tapered air duct 80 is formed between the web plate 70 and the wall surface of the inner cavity of the blade. The tapered air duct 80 can be provided with, but is not limited to, 3 to 4 spiral guide vanes. In order to adapt to the aerodynamic shape of the blade gradually reducing in cross-sectional area from the root to the tip, and to maintain the stable flow velocity of the airflow, the diameter of the air duct is designed to be nonlinearly tapered, smoothly converging from the root to the tip. The contour curve follows the function relationship: D(x) = D root -k x n , wherein D root is the root diameter (about 15 mm), x is the axial position, and k and n are coefficients optimized based on the aerodynamic shape of the specific blade model. The design is based on the flow conservation principle in fluid mechanics (Q = A1 x V1 = A2 x V2), aiming to ensure the stability of the airflow velocity. Simulation analysis and experimental verification show that when a uniform gradient of 0.12 mm / m is used, the flow velocity of the hot air in the entire air duct can be stabilized at 8-12 m / s, effectively avoiding vortex caused by sudden changes in flow velocity. As a comparison, if the diameter change gradient is not properly designed (such as more than 0.2 mm / m), it will lead to excessive wind speed at the tip area (more than 15 m / s), resulting in a sharp increase in air duct resistance, and the system energy consumption will increase by more than 12%.

[0028] The embodiment aims to solve the problems of uneven heat distribution and low thermal efficiency in traditional direct hot air deicing. The cyclone air duct 50 is used to guide the hot air to form forced cyclone, increase the contact area between the hot air and the inner cavity wall of the blade, and increase the heat transfer coefficient by 30%-40%. At the same time, the residence time of the hot air is effectively prolonged to 2-3 seconds, reducing heat loss and improving deicing efficiency. Specifically, the core theoretical basis of cyclone enhanced heat transfer is the correlation model of swirl number (Swirl Number) and Nusselt number (Nusselt Number). The calculation formula of swirl number S w is as follows: S w = (π · D · tan α) / (P · n · h), wherein, D D is the diameter of the air duct, α is the spiral angle, P is the pitch, n is the number of spiral guide vanes, h is the height of the spiral guide vane. Through numerical simulation verification, when the swirl number S w is in the optimization interval of 0.6-0.8, the hot air can form a strong cyclone state without vortex dead angle. At this time, the Nusselt number Nu can be increased by 42%-55% compared with the conventional straight channel, and the actual heat transfer coefficient in the project can be increased by about 30%-40%. Based on the theoretical model, and considering the fluid resistance constraint of the conventional blade length (e.g. 58 meters), the embodiment determines a set of preferred parameters of the cyclone air duct through optimization calculation: the helical guide vanes are designed with equal pitch helix, the pitch is 200-300 mm (the pitch can be adaptively adjusted according to the blade cross-sectional size), the helix angle is 30-45°, the height is 1-2 mm, and the thickness is 1 mm. Preferably, the pitch is 250 mm, the helix angle is 35°, and the helical guide vane height is 1.5 mm. The parameter combination can ensure that the airflow maintains the cyclone number in the full air duct length range S w is stabilized at 0.72±0.03, achieving a balance between heat transfer efficiency and air resistance.

[0029] It should be further explained that the embodiment introduces a phase change microcapsule coating, which undergoes solid-liquid phase change in the hot air temperature range, absorbs and stores a large amount of latent heat, forms a heat buffer layer, and cooperates with the cyclone hot air to make the blade wall surface temperature uniform, and to strengthen the heat transfer efficiency between the ice layer and the blade. The phase change temperature of the phase change microcapsule coating matches the hot air temperature. The cooperative working mechanism of the cyclone hot air and the phase change microcapsule coating 30 is based on the following heat balance equation: Q heat =Q phase +Q trans wherein, Q heat is the heat input by the hot air, Q phase is the latent heat absorbed by the phase change microcapsule coating in the phase change process, Q trans is the heat transferred outward through the blade wall surface (for ice melting).

[0030] In summary, the wind turbine blade deicing system of the 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 arranged at one end of the blade cavity close to the blade root. The heating module includes a heating element 11 and a fan 12 in communication with the heating element 11. The heating module is used to heat the airflow to form a hot air flow. The spiral guide rib 20 is used to form a spiral flow wind channel 50, so that the hot air heated by the heating module forms a spiral flow. The phase change microcapsule coating 30 is coated on at least the inner wall surface of the blade cavity to form a heat buffer layer. The control module 40 is in communication with the heating element 11 and the fan 12, and is configured to adjust the rotating speed of the fan 12 and the heating power of the heating element 11 according to at least the state of the phase change microcapsule coating 30. The wind turbine blade deicing system uses the spiral flow wind channel 50 to guide the hot air to form forced spiral flow, thereby improving the heat transfer efficiency, making the hot air effectively cover each area of the blade, prolonging the residence time of the hot air in the blade cavity, reducing heat loss, and improving the utilization rate of the hot air. In addition, the phase change microcapsule coating 30 can efficiently absorb and store latent heat through solid-liquid phase change, forming a double and synergistic heat effect of “forced convection of spiral hot air + phase change microcapsule coating phase change heat storage and slow release”, which effectively raises the temperature of the blade wall surface quickly and uniformly, thereby improving the deicing efficiency.

[0031] In some optional embodiments, the web plate 70 is coated with a heat insulation aerosol to effectively reduce the heat absorbed by the web plate 70, thereby providing better heat storage enhancement effect for deicing. The thickness of the heat insulation aerosol can be set to 50-100 μm.

[0032] In some optional embodiments, the outlet end of the spiral flow wind channel is formed in a diverging structure, and the expansion angle of the diverging structure is 15°. The theoretical basis of this design is the diffusion pipe flow loss model. Calculation and test data show that, under the expansion angle of 15°, the local resistance coefficient ξ≤ 0.15, which is much lower than the resistance coefficient (ξ=0.32) under the expansion angle of 20°. 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 spiral flow wind channel is provided with a plurality of circumferentially distributed guide ports. Specifically, the outlet end of the spiral flow wind channel is provided with three circumferentially uniformly distributed guide ports, which are oriented to the sensitive areas such as the leading edge and the suction side of the blade, which are most prone to icing, so that the spiral hot air can cover about 95% of the area of the leading edge of the blade, thereby improving the deicing effect. In contrast, the conventional straight cylinder type outlet can usually only achieve a hot air coverage area of about 60%. Therefore, by optimizing the layout of the guide ports, the present embodiment improves the coverage area of the hot air, ensures that the hot air can be effectively distributed to the key areas of the blade, and thereby enhances the deicing capacity of the blade.

[0034] In some alternative embodiments, the material of the blade and the web is an epoxy composite material, which can withstand a temperature of ≥ 120 °C and a pressure of ≥ 0.3 MPa.

[0035] In some alternative embodiments, the phase change microcapsule coating includes, by mass percentage, 40%-50% of the phase change core material, 20%-25% of the microcapsule wall material for wrapping the phase change core material, 20%-25% of the dispersion medium, and 5%-10% of the functional additive.

[0036] For the working condition of hot air temperature of 55-75 °C, it is found through differential scanning calorimetry (DSC) tests that, when n-eicosane (phase change temperature of 36.8 °C) and docosane (phase change temperature of 44.2 °C) are compounded in a mass ratio of 3:2, the phase change temperature can be widened to 60-65 °C by using the eutectic point offset effect, and the phase change enthalpy is ≥ 180 J / g, which can absorb 60%-70% of the heat input of the hot air, thereby forming an effective heat buffer layer. It should be noted that, if the mass ratio deviates from 3:2, for example, adjusted to 2:3, the phase change temperature will decrease to 52-58 °C, which will lead to a decrease in the matching degree with the hot air temperature, and thus the heat storage capacity of the phase change microcapsule coating will decrease by more than 15%, ultimately affecting the uniformity of the blade surface temperature.

[0037] Compared with n-octadecane (phase change temperature of 28 °C, which cannot match the hot air temperature of 55-75 °C) and paraffin (phase change enthalpy of only 150 J / g), the n-eicosane-docosane composite alkane has an overlapping degree of 90% with the hot air temperature when the mass ratio is 3:2, which improves the matching degree. At the same time, the phase change enthalpy is increased by 20%, and there is no crystallization and delamination phenomenon at low temperature (-40 °C). Therefore, in some alternative embodiments, the preferred phase change core material is n-eicosane-docosane composite alkane, and the mass ratio thereof is 3:2.

[0038] In some alternative embodiments, the microcapsule wall material is a polyurea-silicon dioxide composite wall material. Specifically, the microcapsule wall material is prepared by interfacial polymerization, and has a wall thickness of 1-3 μm and a porosity of ≤ 2%, which can effectively prevent leakage of the phase change core material and at the same time improve the thermal conductivity. Compared with a single polyurea wall material (thermal conductivity of only 0.2 W / (m·K)), the polyurea-silicon dioxide composite wall material adds 5%-8% of nano-silicon dioxide to the polyurea, uses the “phonon conduction enhancement effect”, and increases the thermal conductivity of the wall material to 0.5 W / (m·K). This improvement effectively solves the deficiency of traditional phase change microcapsules in “easy heat storage and difficult heat release”. It should be noted that if the content of silicon dioxide exceeds 10%, the brittleness of the wall material will increase, thereby reducing the number of cold and hot cycles from 500 times to less than 300 times. Therefore, maintaining an appropriate content of silicon dioxide is an important factor to ensure the performance of the microcapsule wall material.

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

[0040] In some alternative embodiments, the functional additives include 2%-3% of a coupling agent, 1%-2% of a dispersant, 1%-2% of a film-forming aid, and 0.5%-1% of an anti-aging agent, by mass percentage. Specifically, the coupling agent is γ-aminopropyl triethoxysilane, which serves to enhance the chemical bonding between the coating and the blade composite material and the material of the air duct. One end of the coupling agent (-OEt) can undergo condensation reaction with the hydroxyl groups on the substrate to form Si-O-C bonds, and the other end (-NH2) can react with the isocyanate groups (-NCO) in the polyurea wall material to form urea bonds. In this way, the γ-aminopropyl triethoxysilane forms 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, which is intended to prevent the agglomeration of the microcapsules; 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 ultraviolet absorber, which ensures the durability of the coating for long-term outdoor use.

[0041] In one specific embodiment, the formulation of the phase change microcapsule coating includes 40%-50% of n-eicosane-dodecane composite alkane (with a mass ratio of 3:2), 20%-25% of polyurea-silicon dioxide composite wall material (with a mass percentage of 5%-8% of silicon dioxide), 20%-25% of dispersion medium (deionized water and ethanol with a mass ratio of 4:1), and 5%-10% of functional additives (including 2%-3% of γ-aminopropyl triethoxysilane, 1%-2% of polycarboxylate dispersant, 1%-2% of ethylene glycol butyl ether, and 0.5%-1% of benzotriazole ultraviolet absorber), by mass percentage. The phase change microcapsule coating exhibits excellent performance, with an adhesion of ≥5B grade (ISO 2409) and the ability to withstand 500 cycles of cold-heat cycling from -40°C to 80°C without cracking or peeling, a phase change enthalpy attenuation of ≤5%, and a high-temperature resistance of ≥120°C, demonstrating its reliability and durability in practical applications.

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

[0043] In a specific embodiment, the preset phase change temperature interval 60-65℃ of the phase change microcapsule coating temperature is taken as the controlled quantity, and the PID adjusting unit is specifically configured as follows: when the phase change microcapsule coating temperature is lower than 60℃ (the phase change temperature is not reached), 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 cyclone hot air and promote the phase change microcapsule coating to quickly absorb heat and start the phase change process. When the phase change microcapsule coating temperature reaches or exceeds 65℃ (the phase change heat storage is completed), the hot air temperature is reduced by 3-5℃ and the wind speed is reduced by 0.5-1 m / s. At this time, the latent heat stored by the phase change microcapsule coating is mainly released, and the residual heat of the cyclone is used to maintain deicing, thereby significantly reducing active energy consumption.

[0044] It should be further pointed out that the PID adjusting unit is an incremental PID controller, and the control output formula thereof is: Δu (k) = Kp[Δe(k) - Δe(k-1)] + KiΔe(k) + Kd[Δe(k) - 2Δe(k-1) + Δe(k-2)], wherein Kp=2.5, Ki=0.8, Kd=0.3 , the fluctuation range of the hot air temperature can be controlled within ±2℃, so as to ensure that the thermal stress borne by the blade composite material is lower than the safety threshold of 20MPa, and the structural integrity of the blade is ensured.

[0045] In some optional embodiments, the control module 40 is further configured to predict the icing trend of the blade based on the environmental parameters through a pre-trained icing prediction model, and control the opening and closing of the heating module accordingly. The icing prediction model input parameters include 6-dimensional data such as environmental temperature, humidity, wind speed and blade vibration frequency, which are trained through 1000 groups of cold region measured data, and can accurately predict the icing trend in advance, with an error of ≤0.1mm in predicting the ice layer thickness. Compared with the traditional fixed threshold triggering mode (the error is usually 0.5mm), the embodiment can start the system 2-3 minutes in advance, realizing further reduction of energy consumption (about 8% can be further reduced).

[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 layer thickness is ≥1mm, and to close the heating element 11 and the fan 12 when the predicted ice layer thickness is ≤0.3mm.

[0047] The working process of the wind turbine blade deicing system is as follows: Standby phase: the phase change microcapsule coating 30 is in a normal temperature solid state, the icing prediction model predicts the icing trend, and the system is on standby; Start-up phase: when the predicted ice layer thickness is ≥1mm, the control module 40 issues an instruction to start the heating element 11 and the fan 12; Active deicing and heat storage phase: the hot air forms a stable cyclone through the cyclone air duct 50, passes at high speed through the surface of the phase change microcapsule coating 30, the phase change microcapsule coating 30 absorbs heat and starts to undergo solid-liquid phase change, storing latent heat. At the same time, the cyclone hot air continuously supplies heat to the phase change microcapsule coating 30 and strengthens its heat transfer to the blade wall, forming a double and synergistic heat effect of "cyclone hot air forced convection + phase change microcapsule coating phase change heat storage and slow release". In this phase, the blade wall temperature can be quickly and uniformly raised, accelerating the melting of the ice layer; Finishing and resetting phase: when the predicted ice layer thickness is ≤0.3mm, the control module 40 sends instructions to turn off the heating element 11 and the fan 12. At this time, the phase change microcapsule coating will continue to release its remaining heat storage, ensuring complete removal of residual thin ice. Subsequently, the phase change microcapsule coating naturally cools and solidifies into a solid state, preparing for the next deicing.

[0048] The wind turbine blade deicing system provided by the present application has at least the following advantages: (1) Improved deicing efficiency: the cyclone air duct design causes the hot air to form an efficient cyclone, increasing the heat transfer coefficient by about 35%; when combined with the heat storage effect of the phase change microcapsule coating, the uniformity of the blade wall temperature is improved by 50% (blade temperature deviation not exceeding 5℃), shortening the overall deicing time by 30%-35% compared to traditional systems. For a 5mm ice layer, the deicing time can be controlled within 12 minutes, improving deicing efficiency; (2) Reduced energy consumption: the cyclone prolongs the residence time of hot air in the blade, increasing heat utilization rate to more than 85%, combined with the waste heat recovery function of the phase change microcapsule coating, the comprehensive energy consumption of a single deicing can be reduced to 0.58 kWh or less, reducing energy consumption by 18%-23% compared to the original deicing system; (3) Excellent durability and reliability: the phase change microcapsule coating has good uniformity, adhesion of 5B grade, can withstand cold and hot cycles and vibration impact, and its service life can be synchronized with the blade and air duct, reaching more than 20 years; (4) Wide adaptation range: the cyclone air duct structure is flexible and can adapt to wind turbine blades of different lengths (30-80 meters) and different aerodynamic shapes, and can be stably applied in cold regions and high altitudes at -40℃ to 0℃ and other harsh environments.

[0049] On the other hand, blade coating technology mainly focuses on the corrosion and wear resistance of the outer surface, and lacks a coating designed specifically to strengthen the heat storage and heat transfer in the cavity. Some phase change coating related patents (such as CN202310256789.1) are mainly applied to buildings or electronic devices, and their phase change temperature, adhesion and weather resistance cannot meet the requirements of the working environment of wind turbine blades (-40℃ to 80℃, vibration load, long-term wet and hot 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 coating and curing: low pressure spray of epoxy primer with 50% solid content, controlled dry film thickness of 10-15 pm, and cured at 80 °C for 60 minutes to form a transition bond layer.

[0053] The substrate pretreatment aims to strengthen the interfacial adhesion, making the phase change microcapsule coating form a "physical bite + chemical bond" with the blade composite, thereby improving the adhesion stability of the coating under vibration and cold-heat cycle conditions. This process is mainly based on the "active group grafting-chemical bonding-physical bite" triple mechanism. First, through plasma activation of 3 kW power, the C-C bonds on the surface of the epoxy resin are broken, introducing hydroxyl (-OH) and carboxyl (-COOH) groups. Test results show that the surface energy is increased from 42 mN / m to 65 mN / m, indicating that the surface activity is enhanced. Next, one end of the coupling agent γ-aminopropyl triethoxysilane (-OEt) reacts with the hydroxyl groups on the substrate to form Si-O-C bonds, and the other end (-NH2) reacts with the isocyanate groups (-NCO) on the polyurea wall material to form urea bonds, thereby building 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 pm), which forms a good physical bite with the subsequent coating. This series of treatments synergistically improves the adhesion from the conventional 3B level to the 5B level, significantly enhancing the stability of the coating.

[0054] Further, in the spraying step, an electric high-pressure airless sprayer with a working pressure of 15-20 MPa is used, and a bendable extension spray gun with a length of 2-3 meters and an adjustable nozzle angle (0-90°) is equipped to adapt to the narrow area, curved surface, and outer wall of the air duct. The paint needs to be ultrasonically dispersed for 30 minutes at a power of 300 W before use and filtered through a 200-mesh filter to remove agglomerated particles. During the spraying process, the moving speed of the bendable extension spray gun is 3-5 m / min, the spraying distance is 15-20 cm, and the spraying angle is perpendicular or 45° to the spraying surface. It is worth noting that the phase change microcapsule coating is sprayed on the pretreated substrate surface in 2-3 passes at 25 °C, each pass forming a dry film thickness of 20-30 pm, and the interval between each pass is 30 minutes, with the final total dry film thickness controlled at 50-100 pm. The spraying interval time is based on the solvent evaporation-film formation-crosslinking kinetics. A 30-minute spraying interval can reduce the solvent residue in the previous coating to less than 3%. If the spraying interval is less than 20 minutes, the solvent retention will cause the coating to blister; if the spraying interval is longer than 40 minutes, the previous coating will be over-cured, causing the interlayer adhesion to decrease from 5B to 4B.

[0055] In some optional embodiments, in the spraying step, the key areas with high heat load, such as the inner cavity area of the vane corresponding to the outlet of the spiral air duct, and the inner cavity area of the vane leading edge, are subjected to reinforced spraying. Specifically, an additional 1 pass of reinforced spraying can be performed to make the thickness of the area reach 80-100 μm.

[0056] In the curing step, a segmented curing process is adopted. Specifically, first, the surface is 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 the real dryness, so as to ensure that the coating is fully combined with the base material and the outer wall of the air duct; after the curing is completed, the surface of the coating is lightly sanded using 1000 mesh sandpaper to remove burrs, and finally cleaned by blowing with high-pressure air.

[0057] The specific embodiments of the present application are described in detail below in combination with a 2.5 MW wind turbine blade (length 58 m, inner cavity volume about 12 m³).

[0058] Preparation of the spiral air duct: an epoxy resin composite material is used to form a tapered air duct by integral molding. The tapered air duct is designed to gradually reduce the diameter from the root to the tip, from 15 mm to 8 mm. Three spiral guide ribs are arranged in the tapered air duct, and the spiral guide ribs form a spiral air duct inside. The pitch of the spiral guide rib is 250 mm, the spiral angle is 35°, and the height is 1.5 mm. The outlet end of the spiral air duct is designed in a diverging structure with an expansion angle of 15°, and three circumferential guide ports are arranged with an included angle of 120°.

[0059] Preparation of the phase change microcapsule coating: the coating formula ratio (by mass fraction) is: n-eicosane and docosane composite core material 45%, polyurea and silicon dioxide composite wall material 22%, deionized water and ethanol (4:1) mixture 23%, γ-aminopropyl triethoxysilane 2.5%, polycarboxylate dispersant 1.5%, ethylene glycol butyl ether 2%, and benzotriazole ultraviolet absorber 0.5%. The preparation process of the coating adopts the interface polymerization method to prepare microcapsules with a particle size of 1-10 μm. Subsequently, the microcapsules are mixed with the dispersion medium and additives, and subjected to uniform stirring, ultrasonic dispersion and filtration to obtain the finished coating. The performance test results of the coating show that the phase change temperature is 62°C, the phase change enthalpy is 185 J / g, the adhesion reaches 5B level, no cracking occurs after 500 times of cold and hot cycle, and the surface hardness is ≥2H.

[0060] Spraying process implementation: the substrate (blade inner cavity and air duct outer wall) is purged using high-pressure air; the substrate is wiped with anhydrous ethanol; the substrate is plasma activated (speed of 5 m / min, distance of 12 cm); an epoxy primer is sprayed (thickness of 12 microns); curing is performed at 80 DEG C for 60 minutes; the coating is ultrasonically dispersed for 30 minutes; filtration is performed; the first pass of spraying is performed (spraying thickness of 25 microns, interval of 30 minutes); the second pass of spraying is performed (spraying thickness of 30 microns, interval of 30 minutes); the third pass of spraying is performed (spraying thickness of 25 microns); an additional pass of spraying is performed at the air duct outlet and inner cavity area of the leading edge (spraying thickness of 30 microns); room temperature curing is performed for 2 hours to achieve surface dryness; curing is performed at a constant temperature of 60 DEG C for 2 hours to achieve real dryness; the surface is lightly sanded using 1000 mesh sandpaper; and high-pressure air is used for purging.

[0061] Synergistic deicing operation verification: deicing verification is performed under the following environmental conditions: -15 DEG C, relative humidity of 85%, and ice thickness of 5 mm; the specific process is as follows: 4 minutes after starting, the cyclone hot air rapidly raises the coating temperature to 62 DEG C, completes phase change heat storage, and uniformly raises the blade wall temperature to 58 DEG C, and the ice layer begins to rapidly melt; 11 minutes after starting, the ice layer thickness is reduced to 0.2 mm, the hot air system is turned off, and the coating begins to release heat slowly; 12 minutes after starting, the ice layer is completely removed, and the single deicing energy consumption is 0.56 kWh. Comparative test: the deicing time of the traditional straight channel without coating is 22 minutes, and the energy consumption is 1.05 kWh; in comparison, the deicing efficiency of the embodiment is improved by 45.5%, and the energy consumption is reduced by 46.7%; the deicing time of the traditional straight channel with coating is 19 minutes, and the energy consumption is 0.75 kWh; in comparison, the deicing efficiency of the embodiment is improved by 36.8%, and the energy consumption is reduced by 25.3%.

[0062] Long-term stability verification: after 100 deicing cycle tests, the coating has no peeling or cracking, and the phase change enthalpy attenuation is only 3.2%; the spiral air duct has no deformation or air leakage, and the structural performance is stable.

[0063] The above only describes the embodiments of the present application, and it should be noted that, for those skilled in the art, improvements can be made without departing from the inventive concept, but these all belong to the protection scope of the present application.

Claims

1. A wind turbine blade de-icing system, characterized in that, The application relates to a blade heating system, comprising: a heating module arranged in a blade inner cavity close to a blade root end, comprising a heating element and a fan in communication with the heating element, for heating air flow to form hot air flow; a spiral guide rib for forming a spiral flow air duct, so that the heating module heats the formed hot air to form spiral flow air; a phase change microcapsule coating layer coated at least on a wall surface of the blade inner cavity, for forming a heat buffer layer; and a control module in communication connection with the heating element and the fan, configured to adjust a rotating speed of the fan and a heating power of the heating element according to at least a state of the phase change microcapsule coating layer. The spiral guide rib has a pitch of 200-300 mm, a spiral angle of 30-45 DEG and a height of 1-2 mm. An outlet end of the spiral flow air duct is formed into a gradually expanding structure, and the gradually expanding structure has an expansion angle of 15 DEG. And / or, the outlet end of the spiral flow air duct is provided with a plurality of circumferentially distributed guide ports. And / or, the blade inner cavity is provided with a web, and the web is coated with a heat insulation aerosol.

2. A wind generator blade de-icing system according to claim 1, characterised in that, The phase change microcapsule coating layer comprises a phase change core material and a microcapsule wall material wrapping the phase change core material.

3. A wind turbine blade de-icing system according to claim 1, characterised in that, The phase change core material is a n-eicosane-dodecane composite alkane, and the mass ratio of the n-eicosane to the dodecane is 3:

2. And / or, the microcapsule wall material is a polyurea-silicon dioxide composite wall material. The phase change microcapsule coating layer further comprises a functional additive, and the functional additive comprises, in percentage by mass:

4. A wind turbine blade de-icing system according to claim 1, characterised in that, 2%-3% of gamma-aminopropyl triethoxysilane; 1%-2% of polycarboxylate dispersant; 1%-2% of ethylene glycol butyl ether; 5. A wind turbine blade de-icing system according to claim 4, characterised in that, 0.5%-1% of benzotriazole ultraviolet absorber. The control module comprises a PID adjusting unit taking the temperature of the phase change microcapsule coating layer as a controlled quantity, and the PID adjusting unit is configured to: When the temperature of the phase change microcapsule coating layer is lower than the lower limit of a preset phase change temperature range, the rotating speed of the fan and the heating power of the heating element are increased; When the temperature of the phase change microcapsule coating layer reaches or is higher than the upper limit of the preset phase change temperature range, the rotating speed of the fan and the heating power of the heating element are decreased. The control module is further configured to predict a blade icing trend by using a pre-trained icing prediction model based on environmental parameters, and to control the start and stop of the heating module according to the icing trend.

6. A wind turbine blade de-icing system according to claim 1, characterised in that, The control module is specifically configured to: When the predicted ice layer thickness is greater than or equal to 1 mm, the heating element and the fan are started; and when the predicted ice layer thickness is less than or equal to 0.3 mm, the heating element and the fan are stopped. The application further discloses a method for coating a phase change microcapsule coating layer on a blade inner cavity wall surface, comprising the following steps:

7. A wind turbine blade de-icing system according to claim 1, characterised in that, Substrate pretreatment: performing plasma activation treatment on a substrate surface of a blade inner cavity and a spiral flow air duct outer wall; 8. A wind turbine blade de-icing system according to claim 7, characterised in that, Spraying: using a high-pressure airless spraying device to spray the phase change microcapsule coating material on the pretreated substrate surface in multiple times, and intervaling a preset time after each spraying to form a phase change microcapsule coating layer with a preset thickness; Curing: performing curing treatment on the phase change microcapsule coating layer formed by spraying.

9. A process for the spray application of a phase change microcapsule coating for the manufacture of a de-icing system for a wind turbine blade according to any one of claims 1 to 8, characterized in that, In the substrate pretreatment step, an atmospheric pressure plasma torch is used for treatment, the power of the atmospheric pressure plasma torch is 3 kW, the moving speed is 5 m / min, and the distance between the torch head and the substrate surface is 10-15 cm. ​ ​ ​ 10. The phase change microcapsule coating spraying process according to claim 9, characterized in that, ​ And / or, in the spraying step, the high-pressure airless spraying equipment is equipped with a bendable elongated spraying gun, the moving speed of the bendable elongated spraying gun is 3-5 m / min, the spraying distance is 15-20 cm, and the spraying angle is perpendicular to the spraying surface or 45°. And / or, in the spraying step, the inner cavity area of the corresponding blade of the outlet of the cyclone air duct and the inner cavity area of the leading edge of the blade are intensively sprayed.

Images