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为了更好地预测电枢转捩,建立了3维固体电枢轨道炮内电流熔化波烧蚀的计算模型,采用有限差分法模拟了电流熔化波的形成及传播过程。计算结果表明:在速度趋肤效应作用下,电流向接触表面的尾部边缘集中,Joule热的剧增导致电枢尾端拐角处首先发生烧蚀,并在接触面处形成了从尾部向头部传播的熔化波。熔化波沿接触面的两侧边缘烧蚀较快,而沿中部的烧蚀较为缓慢,形成了一个U形的烧蚀表面。烧蚀缝隙会造成电枢与导轨失接触进而引发电枢转捩。计算结果与经典解析模型及实验结果相比具有良好的一致性。通过模拟并分析电枢接触表面的烧蚀状况,可将计算结果用于预测电枢转捩的发生。
In order to predict the armature rotation better, a calculation model of current wave ablation in 3-D solid armature rail was built. The formation and propagation of current wave were simulated by finite difference method. The results show that the current converges to the tail edge of the contact surface under the effect of velocity skin effect. The sharp increase of Joule heat leads to the ablation at the corner of the caudal end of the armature and the formation of the transition from tail to head Spread the melted wave. The melted waves ablated faster along the edges of both sides of the contact surface, while the ablation along the middle part was slower, forming a U-shaped ablated surface. Ablation of the gap can cause the armature and guide rail to lose contact and cause armature rotation. The calculated results are in good agreement with the classical analytical models and experimental results. By simulating and analyzing the ablation condition of the armature contact surface, the results of the calculations can be used to predict armature rotation.