风机叶片气动脉冲除冰结构脱冰计算模型及试验验证

De-icing Calculation Model of Pneumatic Impulse De-icing Structure for Wind Turbine Blades and Experiment Verification

随着低碳型电力系统建设的发展,风力发电系统的发展速度进一步提升。山地风能资源丰富,然而建设于此的风力发电机在冬季极易覆冰。为减少覆冰造成的风机出力损失,保证风电场电力调度稳定,对风力发电机应用防/除冰技术十分重要。该文提出一种适用于风机叶片的气动脉冲除冰结构,并基于此结构建立相关脱冰计算模型。为了验证该结构的除冰效果和脱冰计算模型的准确性,在人工气候试验室开展了不同温度和冰层厚度下的覆冰与除冰试验。结果表明:随着冰层厚度的增加和覆冰温度的降低,平均除冰气压呈现增加趋势,脱冰面积比出现减小趋势;经验证,该文建立的脱冰计算模型可信度高,基于该模型可知,适当提高变形层的弹性模量和厚度可以增加脱冰面积比。

With the development of low-carbon power system construction,the development speed of wind energy power generation systems is further improved.In cold regions,available wind power is approximately 10%higher than in other regions,due to the increased air density caused by lower temperatures.However,wind turbines built in these places are facing severe icing problems.Ice accretion on wind turbine blades can reduce electric production,and cause unwanted vibration,thus reducing the lifetime of wind turbines.Therefore,it is necessary to apply ice protection techniques to wind turbines.Inspired by the rubber de-icing boot used on aircraft wings,a new structural pneumatic impulse de-icing method was proposed.This method uses modified epoxy resin to cure the expandable flat tube into the protected structure.According to this method,a de-icing calculation model was proposed to guide the subsequent parameter optimization of the de-icing structure.To verify the accuracy of the de-icing calculation model and the de-icing feasibility of the new method,icing,and de-icing tests were carried out in an artificial climate chamber.During the icing test,the thickness of the ice layer covering the test sample included 1 mm,2 mm,and 3 mm,and the icing temperature included-4℃,-8℃,and-12℃.In the de-icing test,the de-icing inflation pressure and de-icing area ratio are used to evaluate the de-icing effects of the sample.Before the de-icing test,the transverse bonding stress between the ice layer and aluminum skin under different icing conditions was measured.As the icing temperature goes down,the transverse bonding stress shows an increasing trend.The measured transverse bonding stress is 0.238 MPa,0.328 MPa,and 0.37 MPa respectively when the temperature is-4℃,-8℃,and-12℃.With the thickness of the ice layer increasing,the transverse bonding stress gets larger gradually.The measured transverse bonding stress is 0.178 MPa,0.218 MPa,and 0.37 MPa respectively when the ice thickness is 1 mm,2 mm,and 3 mm.According to the de-icing test results,it is found that:(1)With the increase of ice thickness,the average de-icing inflation pressure required by the test sample increases obviously,but the de-icing area ratio decreases.The reason for the increase in average de-icing pressure is the increase in transverse bonding stress between the ice layer and the aluminum skin and the deviation of the neutral layer of the composite beam towards the interface of the ice layer and the aluminum skin.(2)With the decrease in the icing temperature,the average de-icing pressure required by the test sample increases,while the de-icing area ratio decreases.The reason for this result is the increase of the elastic modulus of the ice layer and the transverse bonding stress.By comparing the de-icing area ratio results obtained by the calculation model and the de-icing test,it is found that the calculation model can accurately calculate the ice-shedding area.Based on the verified de-icing calculation model,it is found that the de-icing area ratio can be improved by increasing the elastic modulus or the thickness of the deformable layer.However,the two structure parameters should not be increased blindly,which may lead to an increase in the average de-icing inflation pressure,thus increasing energy consumption.