Research On Microwave Heating De-icing Technology For Wind Turbine Blades

With the continuous exploitation and use of fossil energy,it is not only threatened with depletion,but also causes serious environmental problems.In recent years,the country has put forward the "3060" dual carbon target,and wind energy,as an inexhaustible source of clean energy,will continue to develop at a high rate in the next 50 years.China is a vast country with a wide range of wind resources,but extreme weather conditions such as frost and freezing fog in some areas often lead to icing on the blades of wind turbines.Ice can lead to a loss of power in wind turbines and can also lead to safety issues such as ice build-up and falling off the turbines during operation.Numerous studies have shown that icing can lead to power losses ranging from 0.5%to 50%and that ice accumulation leads to a significant increase in blade vibration due to unbalanced blade mass distribution.Therefore,research on anti-/deicing of wind turbine blades is necessary.This paper proposes a microwave heating-based anti-/deicing method for wind turbine blade airfoils.The effect of carbon fibre and carbon black doped media on the microwave properties of wind turbine blades is investigated by numerical simulation using COMSOL multi-physics field coupled simulation software,and microwave heating anti-/deicing simulations are carried out on optimally designed blade composites.The paper uses carbon fibre and carbon black as the filling medium,and numerical simulations investigate the effect of carbon fibre arrangement parameters and carbon black filling parameters on the microwave properties of the composite material.The results show that when the microwave electric field polarisation direction is smaller than the angle between the carbon fibre axial direction,it will significantly increase the microwave reflection coefficient of the composite,while decreasing the transmittance;for composites containing two or more layers of carbon fibre cloth,the larger the angle between different layers of carbon fibres,it will also significantly increase the microwave reflection coefficient of the composite and decrease the transmittance;with the same percentage of reinforcing fibres,reducing the ratio of carbon fibres to In the case of the same percentage of reinforcing fibres,reducing the mixing ratio of carbon and glass fibres can reduce the microwave reflection coefficient and improve the transmittance of the composite.Increasing the carbon black content increases the microwave reflection coefficient and decreases the transmittance;the gradient of carbon black filling in the direction of microwave incidence does not have a significant effect on the microwave properties.Overall the carbon fibre alignment parameters have a more significant effect on the microwave properties of the composite than the carbon black filling parameters.The paper uses a particle swarm(PSO)algorithm to optimise the carbon black filling parameters and the arrangement of carbon fibres in the composite.The results show that the optimum carbon black filling concentration is 3.98%,and at this parameter,the carbon fibres in the composite form a sandwich structure with a dense top and bottom and a sparse middle.This structure significantly increases the reflection effect of microwaves inside the composite,dissipating more microwave energy inside the composite,thus increasing the microwave absorption rate of the composite.The paper couples the electromagnetic field with the temperature field to numerically simulate the microwave heating and de-icing of the blade.The study shows that the presence of ice layers will change the surface temperature of the composite material under microwave heating into three main phases:the warming phase,the constant temperature phase and the rapid warming phase,which is due to the heat absorption process of melting ice layers and the different microwave absorption rates of water and ice.The paper also investigates the effect of microwave power and ambient temperature on de-icing time,which is significantly reduced with increasing microwave power and shortened with increasing ambient temperature.However,the effect of microwave power on deicing time was more significant than that of ambient temperature.