Analyzing Influence of Barrel Shell on Launching Performance of Electromagnetic Rail Launcher
Zhai Xiaofei1, Zou Kun1,2, Li Peifei1, Liu Hua1, Peng Zhiran1
1. National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan 430033 China; 2. School of Electrical Engineering Southeast University Nanjing 210096 China
Abstract：As part of the electromagnetic launcher (EML), the barrel shell mainly provides preloading force for the rails to constrain the EML's expansion and deformation while providing support stiffness for the rail to ensure the straightness of the EML. During the launch process of the armature, the instantaneous change of rail current induces a considerable eddy current on the metal barrel shell of the EML, and the eddy current magnetic field of the shell weakens the magnetic field inside the device. It also affects the current distribution of the rails, thereby affecting the electrical and mechanical properties of the EML and the launching performance, such as the exit speed of the armature. It is necessary to analyze the influence of the shell material and structure on the electromagnetic parameters of the EML and the force of the armature and rails. Firstly, the magnetic field control equation considering the eddy current of the shell is derived. The finite element model (FEM) of the integral, upper-lower separated, and laminated shell structures is established. After the speed frequency is introduced, the frequency-changed current excitation simulates the velocity skin effect caused by the launching of the armature in the bore. Therefore, the inductance gradient and shell loss with frequency change curve, the electric density distribution of the rails, and the eddy current distribution cloud in the shell can be obtained. Secondly, the simulation of electromagnetic-structural is carried out, and the stress distribution of each component of the EML is obtained. The system electrical simulation is established, and the launching simulation results of the three shell structures are compared. It is shown that the laminated structure shell has the smallest eddy current, the largest inductance gradient and device component stress, and the highest armature exit speed. The integral structure shell has the largest eddy current and shell loss, the smallest inductance gradient and device component stress, and the lowest armature exit speed. Finally, the simulation and test results of the laminated structure shell EML are compared, and the errors of the armature exit speed and the current peak are less than 1%. The material selection with high permeability and low conductivity and the shell structure design for suppressing eddy currents are conducive to improving the exit speed and system efficiency of the EML. In addition, reducing the eddy current of the shell can increase the electromagnetic thrust of the armature. However, the external expansion force of the rails will be increased, and increasing the structural strength of the shell is required to provide a higher preloading force. Therefore, the shell's structural design and material selection should consider electromagnetic and mechanical properties for excellent launching performance.
翟小飞, 邹锟, 李配飞, 刘华, 彭之然. 身管外壳对电磁轨道发射装置发射性能影响分析[J]. 电工技术学报, 2024, 39(2): 333-342.
Zhai Xiaofei, Zou Kun, Li Peifei, Liu Hua, Peng Zhiran. Analyzing Influence of Barrel Shell on Launching Performance of Electromagnetic Rail Launcher. Transactions of China Electrotechnical Society, 2024, 39(2): 333-342.
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2024, Vol. 39 
