In this study, we develop a 3D transient mathematic model to simulate the heat transfer, fluid flow, and geometry morphology in GMAW-based wire arc additive manufacturing (WAAM). The processes of droplet formation, growth, and detachment from the end of wire electrode, who travels dynamically along the scanning direction, are coupled with molten pool for the first time by considering their own mechanical conditions and solving the transport equations in the whole solution domain. By the developed model, the simulations of single-pass multi-layer of WAAM of Al-5%Mg are performed. The calculated results indicate that when the droplet falls into the molten pool, the maximum velocity inside the droplet reaches 0.9m/s, resulting in that liquid metal in the middle flows toward the bottom of the molten pool and a depressed region is formed. On the surface of molten pool, the liquid metal dominated by Marangoni force flows from center to periphery, and on the bottom of molten pool, a clockwise circulation is formed. In addition, the interlayer idle time contributes to the formation of deposit with higher height and narrow width. Finally, to validate the model, the deposit profiles are also compared between simulated and experimental results.

在这项研究中，我们开发了一个3D瞬态数学模型来模拟基于GMAW的电弧电弧增材制造（WAAM）中的传热，流体流动和几何形态。沿扫描方向动态行进的液滴从电极丝末端形成，生长和脱离的过程，首次通过考虑其自身的机械条件并在整个溶液域中求解输运方程式而与熔池耦合。通过建立的模型，对Al-5％Mg的WAAM单程多层进行了仿真。计算结果表明，当液滴落入熔池中时，液滴内部的最大速度达到0.9m / s，导致中间的液态金属流向熔池的底部并形成凹陷区域。在熔池的表面上，以马兰戈尼力为主的液态金属从中心向外围流动，在熔池的底部形成顺时针循环。另外，层间闲置时间有助于形成具有较高高度和较窄宽度的沉积物。最后，为验证模型，还对模拟结果和实验结果之间的沉积物轮廓进行了比较。