电工技术学报  2023, Vol. 38 Issue (2): 285-296    DOI: 10.19595/j.cnki.1000-6753.tces.211564
电工理论 |
集磁器对电磁成形驱动线圈发热影响及机理
熊奇1,2, 李青山1,3, 李哲1,3, 赵翔1,3, 李彦昕1,3
1.三峡大学电气与新能源学院 宜昌 443002;
2.华中科技大学国家脉冲强磁场科学中心 武汉 430074;
3.湖北省输电线路工程技术研究中心(三峡大学) 宜昌 443002
Influence and Mechanism of Field Shaper on Heating of Electromagnetic Forming Drive Coil
Xiong Qi1,2, Li Qingshan1,3, Li Zhe1,3, Zhao Xiang1,3, Li Yanxin1,3
1. College of Electrical Engineering & New Energy China Three Gorges University Yichang 443002 China;
2. National Pulsed High Magnetic Field Science Center ; Huazhong University of Science and Technology Wuhan 4430074 China;
3. Hubei Provincial Engineering Technology Research Center for Power Transmission Line China Three Gorges University Yichang 443002 China
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摘要 在电磁成形的过程中,驱动线圈的发热是影响线圈使用寿命和放电频次的关键因素;集磁器作为一种常用的电磁成形辅助工具,目前被广泛用于改善电磁场的分布,提高工件的成形质量。然而,集磁器的引入也会影响等效电路中的等效电感参数,从而改变线圈中的电流,进而影响线圈的发热。故该文提出使用集磁器作为降低管件电磁胀形中驱动线圈发热的措施;通过理论分析和仿真模拟分析了有/无集磁器的两种方案中线圈的发热和管件的成形效果变化,以及集磁器上的温度变化。结果表明,在内径49.6mm、外径68mm、4×10匝的线圈胀形过程中,通过引入集磁器辅助,在放电电压为10.5kV时,线圈上的焦耳热减少了12.32%,最高温度降低了3.42℃,工件的最大成形深度提升至约为原来的2.76倍;进一步的分析则表明,集磁器的引入降低了等效电路中的电感和电压,使得线圈电流具有更陡的下降沿,衰减速度变快的同时减小了电流峰值,从而让线圈的热量损耗更小。该方法成本较低,容易实现,且对于线圈发热问题具有明显的优化效果,对提高电磁成驱动线圈的使用寿命和放电频次具有重要意义。
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熊奇
李青山
李哲
赵翔
李彦昕
关键词 电磁成形驱动线圈集磁器线圈发热耦合互感    
Abstract:As an emerging metal processing and forming technology, electromagnetic forming (EMF) has been widely studied by domestic and foreign experts because of its unique technical advantages. The electromagnetic environment in the process of EMF is very harsh. Existing studies have confirmed that the electromagnetic heat loss of the drive coil is caused by the accumulation of Joule heat, and the electromagnetic heat in the EMF process will affect the structural strength of the drive coil, which in turn reduces the service life and frequency of the coil. The coil performance will be improved by reducing the electromagnetic heat loss of the coil. The integral area of the coil current will be reduced, as the electromagnetic heat loss of the drive coil is due to the accumulation of Joule heat. Based on this, this paper proposes an optimization method for solenoid coil heating.
Firstly, by analyzing the temperature field in the EMF system, it is proposed to use a filed shaper to assist the forming to reduce the coupling mutual inductance of the system, the reduction of time constant results in the decrease of the integral area of the coil current and finally achieving the purpose of reducing the electromagnetic heat generated by the coil. At the same time, the inductance matrix of the solenoid coil, the forming workpiece, and the field shaper is calculated to support this. Through the finite element method, the temperature field is introduced on the basis of the electromagnetic-structural field coupling model, and a fully coupled electromagnetic-structural-temperature field model considering the change of the resistivity of the materials used in each component of the EMF device with temperature is established to verify the feasibility of the forming scheme.
The simulation results show that the electromagnetic expansion of pipe fittings is carried out by using a drive coil with an inner diameter of 49.6mm, an outer diameter of 68mm, and a turn count of 4×10 turns, with the help of introducing a filed shaper when the discharge voltage is 10.5kV, the maximum temperature of the coil is reduced by 12.35%, which is 3.42℃. The Joule heat generated by the coil decreased by 12.3%, a reduction of 0.7kJ. The filed shaper reaches a maximum temperature of 45℃ at 0.2ms, but drops to 31.7℃ at 10ms (when the coil current decays to 0); The magnetic flux density in the workpiece is increased by 21.2% and the induced eddy current density is improved by 3.94%, resulting in a 5.72% enhancement in the Lorentz force on the workpiece. The final forming volume has grown 176%, from 2.52mm to 6.96mm.
The results show that: ① The heat loss of the coil is the result of the gradual accumulation of coil current, and the integral region of the current is proportional to the Joule heat generated by the coil. After the introduction of the field shaper, the coupling mutual inductance in the system is reduced, thereby reducing the equivalent inductance value in the original dynamic circuit and accelerating the attenuation rate of the current in the coil. It alsobrings a reverse voltage, so that the equivalent voltage decreases, resulting in a decrease in the peak value of the current; The combination of the two reduces the additional current losses. ② The induced eddy current in the field shaper has a very short acting time, and compared with the coil, the surrounding air circulation is better, which is easy to do the cooling treatment. ③ Under the same deformation conditions, the introduction of magnetizer assistance can reduce the initial discharge energy and reduce the temperature rise of the coil, which is a simple and effective way to improve the service life and efficiency of the coil.
Key wordsElectromagnetic forming    drive coil    field shaper    coil heating    coupling mutual inductance   
收稿日期: 2021-09-30     
PACS: TM154  
基金资助:国家自然科学基金(51707104)和武汉强磁场学科交叉资金(WHMFC202121)资助项目
通讯作者: 熊 奇 男,1990年生,博士,副教授,研究方向为脉冲强磁场工业应用、输电线路设备电磁场分析。E-mail: pandaqi0218@gmail.com   
作者简介: 李青山 男,1998年生,硕士研究生,研究方向为电磁场分析与应用。E-mail: rillusion4682@gmail.com
引用本文:   
熊奇, 李青山, 李哲, 赵翔, 李彦昕. 集磁器对电磁成形驱动线圈发热影响及机理[J]. 电工技术学报, 2023, 38(2): 285-296. Xiong Qi, Li Qingshan, Li Zhe, Zhao Xiang, Li Yanxin. Influence and Mechanism of Field Shaper on Heating of Electromagnetic Forming Drive Coil. Transactions of China Electrotechnical Society, 2023, 38(2): 285-296.
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