Abstract: Gas-solid two-phase flow theory is used to simulate the powder flow from coaxial nozzle in coaxial powder feeder system with carrying gas, which is the key technology in laser manufacturing. The concentration distributing of powder flow and powder parameters (focus distance to nozzle exit and focus radius of powder flow) varying is simulated and analyzed. The numerical simulation result is well consistent with the result of measurement by digital particle image velocimetry (DPIV). It is shown that the concentration of powder flow and powder pa-rameters is also influenced by gas flux and feeding powder amount. It can be found that the gas flux mainly affects the powder velocity and the powder concentration or focus pa-rameters hardly change with various gas fluxes and constant feeding powder amount. The powder concentration tends to increase with increasing powder feed amount. The focus dis-tance and powder stream radius at the focus point also increase and focus depth decreases with increasing the feeding powder. The powder flow simple model is also presented. The conclu-sion will benefit for coaxial nozzle designing and performance improving.

Key words: Coaxial powder feeding, Gas-solid two-phase flow, Laser manufacturing, Numerical simulation