Numerical Simulation of Unsteady Arc in GTAW with Alternate Axial Magnetic Field

doi:10.3901/JME.2018.16.079

Abstract

Abstract: Based on the computational fluid dynamics(CFD) software Fluent, the alternating magnetic field controlling unsteady electric arc properties such as temperature field, flow field and pressure field in extra alternate axial magnetic field are studied by modeling a 3D mathematic model of gas tungsten arc welding(GTAW). The relationships of maximum temperature、pressure distribution on the anode and current density on the anode with time are highlighted. When taking into account the alternate axial magnetic field, the extra electromagnetic force drives the arc to rotate. The maximum accelerated speed reaches 6×10⁷ m/s², hence the arc plasma nearing the tungsten suddenly changes its rotating direction, and arc plasma away from that keeps intact. The arc can ultimately alter its rotating direction when the magnetic field frequency is less than 100 kHz when the magnetic induction intensity is 0.03 T. The pressure and current density distributions on the anode change from double peaks to one-two peaks alternating periodically, which have been partly demonstrated in the experimental research by high-speed camera system. It ultimately provides fundamental basis for the alternating magnetic field controlling welding technology.

Key words: alternate axial magnetic field, gas tungsten arc welding, numerical simulation

CLC Number:

TG444

XIAO Lei, FAN Ding, HUANG Jiankang. Numerical Simulation of Unsteady Arc in GTAW with Alternate Axial Magnetic Field[J]. Journal of Mechanical Engineering, 2018, 54(16): 79-85.

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