According to Maxwell's equations and heat-conduction differential equation, a mathematical model is developed to describe the distribution of electromagnetic field, inductive eddy current and thermal field for multi-stage induction coilgun. Based on the finite element method(FEM) analysis of electromagnetic and thermal fields, a three-dimensional FEM model is built. When ignoring the inter-stage effect, armature temperature rise calculated in multi-stage is equivalent to multiple armature temperature rise calculated in single-stage, the practical induction heating quenching process is simulated by using ANSYS software. The rela tionship between the physical parameters of the coilgun and the resulting temperature is considered during the computation. The simulated results indicate that: 1. Temperature rise inside of the armature is concentrated in the exterior surface and the tail of the armature. 2. Temperature of the armature rises when voltage and capacity increases, because of increasing eddy current. 3. Trigger position and speed match relation of the armature influence temperature of the armature greatly. 4. Temperature of the armature in creases by increasing stage numbers of coilgun before the armature is melted. The results provide reference for the multi-stage coilgun project and its application.%从麦克斯韦方程组和导热微分方程出发,导出了3维多级感应线圈炮电磁场、温度场分布的基本方程,并以电磁场和温度场有限元分析为基础,建立了3维有限元分析模型,忽略级间的相互影响,多级线圈炮中电枢温升可以等效为多个单级电枢的温升,运用通用有限元分析软件ANSYS的耦合计算流程,对单级感应线圈炮中电枢电磁场和温度场进行仿真.计算中考虑了材料物理参数随温度变化对温度场的影响.仿真结果表明:电枢内的温升主要分布在电枢的外表面和尾部;电枢的温度随着电容器组电压和电容增加而升高,这是因为总能量增大,电枢中涡流也增大,从而电枢的温度升高;电枢的触发位置和速度匹配关系,也会对电枢温升造成很大的影响;电枢的温度随着级数的增加逐渐升高,说明电枢在一定级数后达到了材料的熔点而被破坏.
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