Numerical Simulation of Temperature and Flow Field of Molten Pool During CMT-WAAM Process Based on Dynamic Mesh Technique
In the weaving wire arc additive manufacturing(WAAM)of magnesium alloy,enhanced by the cold metal transfer(CMT)technique,a three-dimensional transient numerical model is employed to investigate the temperature and velocity fields during the process.Utilizing the volume of fluid(VOF)method and dynamic mesh(DM)technique,this model accounts for the forces exerted on the droplet and molten pool.The model's accuracy is demon-strated through experimental validation,with the simulation parameters related to the molten pool and droplet size showing a margin of error under 10%.In the beginning of CMT-WAAM,the molten pool forms on the substrate and the droplet forms at the wire tip owing to arc heat.As the wire feeds into the molten pool,the droplet expands into a spherical shape driven by surface tension.Heat transfer occurs mainly through thermal conduction,causing the peak temperature of the molten pool to rise to 2100.0 K with the droplet transfer,then drop to 1763.6 K as the wire re-tracts.The maximum velocity of the droplet decreases from 1.87 m/s to 1.07 m/s during its incorporation into the mol-ten pool,while the molten pool maintains a maximum velocity of 0.87 m/s.When the droplet meets the molten pool,the maximum velocity of the liquid metal reaches 4.21 m/s.As the wire is withdrawn,this velocity fluctuates between 1.69 m/s and 4.90 m/s.During a short circuit,the metal from the droplet flows from the surface of the molten pool to its bottom and sides,enhancing the stirring effect and increasing the volume of the molten pool.Once the droplet detaches from the wire,the liquid metal moves from the bottom back to the surface and sides of the molten pool,leading to a decrease in temperature and fluid velocity,which moderates the volume of the molten pool.In addition,the free surface of the molten pool exhibits wavy deformation influenced by the weaving arc.
dynamic meshwire arc additive manufacturing(WAAM)droplet transfermolten pool flownumerical simulation
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维普
