基于动网格的CMT焊接电弧形态和温度场数值模拟

Numerical Simulation of Arc Shape and Temperature Field of CMT Welding Based on Dynamic Mesh

CMT(Cold Metal Transfer)焊接是一种全新的MIG/MAG焊接工艺,它不仅有向前送丝的动作,而且还有往回抽的动作。根据这一机械动作特点,先利用前处理软件Gambit对CMT焊接模型进行物理建模、网格划分和边界条件设定,再利用Fluent软件中的动网格技术进行数值模拟,得出CMT焊接电弧在不同时刻的形态和温度场的变化。结果表明:焊丝在前进过程中电弧呈压缩趋势,温度先维持不变,直到前进方向结束时,温度瞬间降到最低,熔滴释放;焊丝回抽时电弧形态扩展,温度逐渐上升,然后维持最高温度一直不变,直到回抽结束。

CMT welding is a new kind of MIG/MAG welding technology. It has not only the movement of sending wire forward, but also the action of drawing back. According to the characteristic of the mechanical movement, the physical model, grid division and boundary conditions of CMT welding were set up firstly based on the Gambit software, then the CMT welding was simulated by using dynamic mesh technique of the Fluent soRware, and finally the arc shape and temperature field of CMT at different time were got. The results show that the arc presents a trend of compression in the process of wire advancing, and the temperature remains unchanged. At the end of the forward direction, the temperature drops to minimum, and the droplet releases. When the wire is drawing back, the arc shape expands, the temperature increases gradually, and then it maintains the highest temperature until the end of withdrawing.