静态下P-MFCG的不同形状电枢受力的仿真

Analysis of Lorentz Force Act on Different Shapes Motionless Armature of P-MFCG

活塞式磁通压缩发电机(P-MFCG)作为一种可重复使用的脉冲功率发电机,在电磁发射器的供电电源方面具有广阔的应用前景。发电机电枢上所受的洛伦兹力(电磁力)对发电机的发电效能有至关重要的影响。不同形状的电枢对螺旋线圈内部磁场强度和位形分布的影响不同,在螺旋线圈内所受的洛伦兹力也不同。该文首先对电枢的受力和作用进行了理论分析,得出影响发电效率的是电枢所受洛伦兹力的轴向分量。其次,通过理论计算,得出电枢表面所受轴向力最大时,电枢表面元法向矢量与该处磁感应线矢量应当满足的关系。然后,利用电磁场有限元分析软件Ansoft,对五种不同形状电枢上感应涡流所受的洛伦兹力进行了仿真。所得数据表明圆柱状电枢所受的轴向洛伦兹力最大,锥状次之,是其70%,但都是分布在电枢的棱边上;类半椭球状电枢受力最小,但分布最均匀;而另外两种电枢的形状相比之下没有优势,不可取。这些结论为电枢的优化设计提供了理论依据,也为P-MFCG的进一步研究提供了重要参考。

As a kind of pulse generator,piston-type magnetic flux compression generator（P-MFCG is suitable for the electromagnetic launcher.The Lorentz force acting on armature influence the generate efficiency.The shape of armature is a critical parameter,which helps to decide the distribution and intensity of magnetic field in helix winding region.With different shapes,the armatures induct different eddy currents and act different magnetic force（Lorentz force）.In this paper,analyzed the force acting on armature when it＇s sliding,and concluded that the bigger the Lorentz force along axial direction acted on armature,the higher the generate efficiency was.And the Lorentz force along axial direction act on armature was discovered to reach a peak value,only when the normal vector of armature infinitesimal surface and the vector of magnetic induction line satisfy a special relation.Then,five different shapes armature were simulated by finite element analysis soft-Ansoft,and the conclusion reached that the cylinder armature could obtain a strongest Lorentz force along axial direction,the pyramidal armature just smaller than the cylinder one;but both of them are distributed non-homogeneous;the semiellipsoid armature has a weaker but homogeneous distribution axial direction Lorentz force;and the other two has few advantages to P-MFCG.The conclusion provided us a reference criterion for armature optimal design of P-MFCG.