飞机和风机叶片除冰用脉冲线圈结构对瞬态电磁场影响研究

Study of the Effect of Pulsed Coil Structures on Transient Electromagnetic Fields for Aircraft and Wind Turbine Blade De-Icing

在飞机和风机叶片电脉冲除冰中,为了提高线圈的脉冲效果,降低除冰装置质量,实现系统的微功耗设计,需要优化线圈结构。脉冲线圈作为脉冲除冰、脉冲焊接等应用中能源转换的关键部件,其瞬态电磁场求解复杂,一般难以得到解析解。为了研究线圈结构参数对脉冲效果的影响,该文通过推导脉冲线圈的场-路数学方程,建立脉冲线圈和目标物的物理模型,并采用有限元软件对脉冲线圈的瞬态电磁场进行计算,得到脉冲线圈电磁参数时变特性。通过脉冲线圈的脉冲冲量试验对模型的准确性进行验证,在此基础上,分析线圈匝数、截面尺寸和线圈匝间距等结构参数对脉冲电流、脉冲力、脉冲效果的影响,为电脉冲除冰应用微功耗化设计提供优化思路和技术路线。

Electro-impulse de-icing of atmospheric structures is a low-power consumption and fast de-icing method.Pulsed coil is a key component in the conversion of energy for electro-impulse de-icing.Of which the structural parameters need to be optimized,so as to improve the de-icing effect of the electro-impulse de-icing system and promote the development of the system’s low-power consumption and lightweight.Most researches on pulsed coil at home and abroad focus on the electrodynamics,structural dynamics and de-icing effect on the target.However,the influence of different structural parameters on the transient electromagnetic fields and impulse effects of pulsed coils has been little studied.Aiming at the above problems,this paper started from the basic principle of circuit and electromagnetic field,simplified the electro-impulse de-icing system,deduced the field-circuit mathematical equation of pulsed coil,established the physical model of pulsed coil and rectangular cross section target,and determined the circuit parameters,the governing equation and boundary conditions of transient electromagnetic field.Based of which,the calculation methods of magnetic induction intensity,target eddy current,impulse force and impulse were obtained.The transient electromagnetic field of the pulsed coil is analyzed by finite element software,and the time-varying characteristics of the pulsed coil’s electromagnetic parameters were obtained.In this paper,the electrical parameters and transient electromagnetic fields under different coils were calculated,which shows that the presence of the target had a great influence on the resistance and inductance of the pulsed coil.The circuit parameters and impulse effects of 40,50 and 60 turns pulsed coils are measured by the impact pendulum test,which verifies the correctness of the model.Through comparative analysis,it is found that:(1)the number of turns has a great influence on the peak value of the pulse force.With the increase of the number of turns,the impulse effect gradually increases.However,the gradual increase in the outer diameter of the coil leads to an increase in coil impedance and a decrease in pulse frequency,making it impossible to achieve de-icing at high strain rates,in particular,the outer diameter of the coil exceeding the outer diameter of the target.(2)Excessive increase in coil height will reduce the impulse effect.With the increase of the coil height,the non-uniform distribution characteristics of the pulse current in the coil become more obvious,especially the pulse current density in the area far from the target increases,resulting in the reduction of the impulse effect.(3)With the increase of the coil turn-to-turn distance,the distribution of the pulsed coil is wider,which makes the pulse force on the target more uniform,but the peak of the pulse force density still appears in the middle region of the coil.(4)The outer turns of the coil have greater influence on electromagnetic parameters and impulse effect than the inner turns.By reasonably limiting the height of the coil cross-section and adjusting the number of turns,cross-section,turn-to-turn distance and inner and outer diameter of the coil in combination with the target material,dimensions and icing,the optimal structural parameters of the pulsed coil under fixed circuit parameters were obtained(60 turns winding,0.8 mm×2 mm wire diameter,1 mm turn spacing,72 mm inner diameter and 190 mm outer diameter).Under the initial conditions of C=400μF and U0=DC 1200 V,the pulse force of 6.9929 kN on the target,with a peak time of 210μs and a pulse impulse of 2.5916 N·s.The corresponding de-icing tests on aluminum plates were carried out using the above pulsed coil with good de-icing results.