变位磁场作用电弧增材中电弧和熔池传热与流动数值模拟

Numerical simulation of heat transfe Numerical simulation of heat transfer and flow of arc and molten pool in arc additive under r variable magnetic field

为了揭示具有纵向和横向分量的外加变位磁场对TIG电弧增材成形过程中电弧和熔池传热与流动的影响机理,基于流体动力学软件Fluent,建立了电弧与熔池耦合的三维瞬态模型。对比分析了不同角度的变位磁场对电弧形貌、电磁力、热流密度、熔池形貌及熔池速度场的影响规律与机理。结果表明:无外加磁场时,电弧与熔池对称分布,施加变位磁场时,电弧和熔池中产生周向旋转和偏向一侧的电磁力,使电弧与熔池发生旋转与偏移,熔池除了具有由内向外的流动,还具有围绕中心旋转和偏向一侧的流动;增大变位磁场的变位角度使横向磁场分量减小,纵向磁场分量增加,从而使偏向一侧的电磁力减小,周向旋转电磁力增大,进而使电弧偏转与熔池偏移减弱,熔池旋转流动趋势增强。研究结论可为后续磁控电弧增材制造传热、传质的机理分析及工艺参数的选择提供理论依据和参考。

In order to reveal the influence mechanism of the external displacement magnetic field with longitudinal and transverse components on the heat transfer and flow of arc and molten pool in the process of TIG arc additive forming,a three-dimensional transient model of arc and molten pool coupling was established based on the fluid dynamics software fluent.The effects of different angle displacement magnetic fields on arc morphology,electromagnetic force,heat flux,pool morphology and pool velocity field were compared and analyzed.The results show that when there is no applied magnetic field,the arc and the molten pool are distributed symmetrically.When the modified magnetic field is applied,it and the welding current in the arc and molten pool produce circumferential rotation and lateral electromagnetic force,which makes the arc and molten pool rotate and shift.The molten pool not only flows from inside to outside,but also rotates around the center and lateral flow.Increasing the displacement angle of the displacement magnetic field decreases the transverse magnetic field component and increases the longitudinal magnetic field component,thereby reducing the lateral electromagnetic force and increasing the circumferential rotating electromagnetic force,thereby reducing the arc deflection and pool migration and increasing the pool rotational flow.The research results can provide theoretical basis and reference for the mechanism analysis of heat and mass transfer and the selection of process parameters in the subsequent magnetron arc additive manufacturing.