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以脉冲电流作为激励的电磁轨道炮可在封装上感应出很大的涡流,涡流密度的高度集中将危害绝缘层的性能和寿命,而且,涡流的存在削弱了电枢的推进力,导致弹丸出口速度减小。为此基于电磁轨道炮3维瞬态有限元模型,分析了封装上涡流的分布,对涡流损耗进行了计算,并通过改变封装材料、封装尺寸、脉冲电流幅值与波形等影响因素研究了涡流能耗、最大涡流密度以及电枢推进力的变化规律。结果表明:高磁导率低电导率的材料作为封装能有效的抑制涡流,大幅提升电枢推进力;增大封装内径或减小其厚度对涡流的抑制比较有限;减小脉冲电流的幅值并加宽波形的平顶可使涡流的危害降至最低。
The electromagnetic rail gun with pulse current as an excitation can induce a large eddy current on the package. The high concentration of the eddy current will endanger the performance and life of the insulation layer. Moreover, the eddy current weakens the propulsion force of the armature, Speed reduced. Based on the 3-D transient finite element model of the electromagnetic rail gun, the distribution of the eddy current on the package is analyzed, and the eddy current loss is calculated. The eddy current is analyzed by changing the factors such as packaging material, package size, pulse current amplitude and waveform, Energy consumption, maximum eddy current density and armature propulsion. The results show that the material with high permeability and low conductivity can effectively suppress the eddy current and greatly enhance the armature propulsion force. Increasing the package inner diameter or reducing its thickness has a limited effect on the eddy current, and the amplitude of the pulse current And broaden the flat top of the waveform eddy current hazards to a minimum.