Numerical simulation of the focused powder streams in coaxial laser cladding

The powder flow structures of a coaxial nozzle for laser cladding was simulated by the numerical programme FLUENT with various arrangements of the nozzle exit. Both focused and columnar powder streams could be generated in a coaxial nozzle. It can be found that the concentration mode is influenced significantly by the nozzle arrangement and gas flow settings. According to the numerical results, more than 50% powder concentration can be increased in a gas stream through a specific nozzle arrangement for coaxial laser cladding. (C) 2000 Elsevier Science S.A. All rights reserved.