Numerical simulation and experimental study on the influence of the length of guide tube and atomization pressure on gas reflux
Spherical powder for metal 3D printing is generally prepared by the technology of atomization,the met-al powder prepared by electrode induction-melting gas atomization(EIGA)without crucible has the advantages of low oxygen increment,high fine powder yield,high sphericity and good fluidity.In this paper,a numerical simula-tion of the airflow field at the bottom end of the guide tube of the atomizing nozzle is carried out,and the influence of the length of the guide tube and the atomization pressure on the gas reflux is studied,and the simulation results are verified by the atomization experiment.The results show that there is a critical value for the length of the guide tube.When the length is lower than the critical value,the flow velocity of the gas outside the annular seam of the atomizing nozzle is higher than that inside,and the gas is easy to return to the inside of the guide tube,resulting in more defective powders.When the length is higher than the critical value,the flow velocity of the gas inside the annular seam is higher than that outside,the gas reflux disappears,and the number of defective powders is greatly reduced.The atomization pressure mainly affects the particle size of the powder.The greater the atomization pres-sure,the smaller the powder particle size.
metal 3D printingspherical powderatomizationguide tubegas reflux
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