中文摘要：

双丝共熔池气体保护焊（TCGMAW）的熔滴过渡对焊缝成形以及焊接质量具有重要的影响．文中根据高速摄影结果，建立了TCGMAW熔滴过渡的运动轨迹，从理论上分析了熔滴过渡的特点，并根据分析结果建立了贴体坐标系下熔滴带入熔池的热量和动量的数学模型，研究了熔池各个表面上的动量和能量边界条件，在此基础上进行了焊缝形状的数值模拟，并与实验结果进行了对比分析．结果表明，所建立的数学模型是可行的，与实际的试验结果比较吻合．

英文摘要：

The droplet transfer in the twin-wire co-pool gas-shielded metal arc welding （TCGMAW） process greatly affects the welding seam appearance and the welding quality. In this paper, the transfer trajectory of the droplet in TCGMAW process is explored according to the high-speed photographing results, and the characteristics of the droplet transfer are theoretically analyzed. Then, some mathematical models are set up in the body-fitted coordinates based on the analytical results to describe the heat and momentum inputs caused by the droplets entering the molten pool, and the boundary conditions of momentum and energy on each surface of the molten pool are investigated. Moreover, a numerical simulation is performed for the welding seam appearance. The results are finally com- pared with the experimental ones. It is found that the simulation results accord well with the experimental ones and that the proposed model is of excellent feasibility .