The Study Of Arc Simulation On Twin-cable 14-wire GMAW

Twin-cable 14-wire GMAW arc is an efficient,energy saving,high-quality innovative welding method based on double-wire GMAW.At its initial study stage,this new welding method has not been applied widely.Based on hydrodynamics software FLUENT,simulation study over arc behavior during twin-cable 14-wire GMAW arc and double-wire GMAW have been conducted,as well numerical simulation results have been verified by high-speed photography.Firstly,3-D numerical model of double-wire GMAW has been built to carry out researches over temperature field,velocity field,pressure field of double-wire GMAW under different welding current,different shielding gas flow,different double-wire spacing,and unequal current conditions.The results showed that with increasing welding current,the maximum temperature of arc,plasma flow velocity and pressure show an increase trend.As well,current density and pressure in the proximity of workpeice transformed from bimodal to unimodal.When the shielding gas flow increases,the maximum temperature,velocity,pressure in the end of welding wire show a decreasing trend before increasing to maximum value,current density and pressure in the proximity of workpeice transformed from bimodal to unimoda with increasing shielding gas flow.The maximum temperature of arc show a decreasing trend slightly,maximum plasma flow rate increases,maximum pressure changed slightly.With increasing double-wire spacing,however,current density and pressure in the proximity of workpeice transformed from bimodal to unimoda.When the double-wire spacing is relatively low,two arcs coupled to a large arc;when the double-wire spacing is too large,two separated arcs formed.Under unequal condition,the maximum temperature,velocity and pressure appeared in the welding wire with higher current,current density and pressure distributed asymmetrically in the surface of workpeice,the maximum value is at the center.Secondly,3-D numerical model of twin-cable 14-wire GMAW was built to study the temperature field,velocity field,and pressure field distribution under different welding current,different shielding gas flow,different double-wire spacing.The results showed that with increasing welding current,the maximum temperature field,velocity field,pressure field of twin-cable 14-wire GMAW arc all increased,but compared with double-wire GMAW,its maximum temperature,velocity and pressure field decreased;the maximum velocity of plasma flow changed,different from pressure distribution of bimodal to unimodal for workpeice surface of double-wire GMAW,and the pressure transition from unimodal to bimodal in the workpeice surface of twin-cabled welding wire.When the flow of shielding gas increases,different from the decreasing trend before increasing of double-wire GMAW for arc temperature,plasma velocity and arc pressure,the maximum temperature of twin-cabled welding wire GMAW,plasma flow rate and pressure field showed an increase trend.The welding arc shape of twin-cabled welding wire,like that the double welding wires shrink in the center of arc,with increasing shielding gas rate,its shrinkage weakened,bonding portion decreased.The maximum velocity field and pressure field are different from double-wire GMAW,the pressure distributed in a unimodal manner.With increasing double-wire spacing,the maximum temperature of twin-cabled welding wire GMAW didn’t show an obvious change,influenced greatly the welding arc shape,as well,velocity field and pressure field decreased gradually with increasing double-wire spacing,and the distribution place changed.For twin-cabled welding wire GMAW,pressure field distributed always in a unimodal manner.With increasing double-wire spacing,the maximum value decreased.Finally,the numerical results were verified via high-speed imaging,it shows that their welding arc shapes were identical,the bonding area of arc increased with increasing welding current.Because of different test conditions and numerical calculation methods,slight difference existed,but showed good accordance.