基于FLUENT软件的GMAW焊熔池动态行为数值分析模型

A numerical analysis model of weld pool dynamic behavior in GMAW based on FLUENT software

基于FLUENT软件,建立了适用的熔化极气体保护焊(gas metal arc welding,GMAW)熔池动态行为数值分析模型,该模型考虑了气—液—固三相耦合.将电弧热输入视为双椭球体热源模型,将电弧等离子体描述为高速流向熔池的氩气,其流速呈高斯分布,流速峰值依据焊接电流确定,电弧压力与电弧等离子体对熔池表面的切应力在计算过程中获得;将熔滴过渡视为高温液态金属从熔池上部一定区域以一定速度流入熔池过程,通过对流速施加时间脉冲函数表征熔滴过渡频率.利用该模型对不同条件下GMAW焊熔池热场及流场进行模拟计算,并分析其流体动力学特征.结果表明,模型能够合理地反映熔池动力学特征,同时还提高了计算效率.

Based on FLUENT software,an adaptive numerical analysis model of weld pool dynamic behavior in gas metal arc welding(GMAW)was developed which considered the three phase coupling of gas-liquid-solid phases.The arc heat input was regarded as a double ellipsoid body heat source,and arc plasma was treated as argon gas flowing toward the weld pool in high velocity.The flow velocity of argon gas was assumed to be a Gaussian distribution mode,and its peak value was determined by welding current.The pressure and shear stress exerting on weld pool free surface due to arc plasma were obtained in the calculation.The droplet transfer was assumed as the process of high-temperature metal liquid flowing into weld pool from the certain region above it and the time pulse function was applied to flow velocity of liquid metal for considering the droplet transfer frequency.Using this model,the temperature and velocity fields in GMAW were computed under different welding conditions and fluid dynamic feature of weld pool was analyzed.The results show that the established model can reflect the dynamic feature of weld pool more reasonably and the calculation efficiency is also enhanced.