穿孔等离子弧焊接热场和流场的数值模拟

Numerical simulation of temperature field and fluid flow in keyhole plasma arc welding

关键词:  穿孔等离子弧焊接  小孔  流体流动  数值模拟

Key words:  K-PAW  keyhole  fluid flow  simulation

摘要:

考虑熔池和小孔的耦合作用,建立了穿孔等离子弧焊接热过程的三维瞬态模型.采用焓孔隙度法处理了凝固熔化过程中相变潜热以及动量损耗问题.基于流体体积函数法(VOF)对小孔界面实施追踪.对等离子弧焊从小孔形成到穿孔的瞬态演变行为、熔池流场的动态变化过程进行了数值模拟.开展了穿孔等离子弧焊接试验,对数值模拟结果进行了试验验证.结果表明,计算得到的流场数量级符合实际,而且得到的熔合线走向与试验结果基本吻合.

Abstract:

With considering the coupled behaviors of weld pool and keyhole, a three-dimensional transient model of thermal process in keyhole plasma arc welding is established. The enthalphy-porosity technique is used to deal with latent heat and momentum loss during melting and solidification. The keyhole boundary is tracked by VOF method. The transient evolution of keyhole geometry from its establishment to its open status, and dynamic variation process of fluid velocity field in weld pool are computed. Keyhole plasma arc welding experiments were conducted to validate the predicted results. The results show that the magnitude of the simulated velocity corresponds to reality and the trend of the fusion line is close to the experiment.