3D numerical simulation of coaxial powder feeding nozzle powder convergence characteristics

In the laser metal direct manufacturing, gas-solid two-phase flow theory is considered to simulate the inside and outside flow field of coaxial powder feeding nozzle with carrying gas to obtain cladding parts of less characteristic size and compact structure. In order to improve the manufacturing precision, the discrete model in FLUENT was used to simulate the effect of process parameters variations on the powder concentration distribution. The results show that powder concentration increases with the powder feeding rate, obviously decreases with the carrier gas velocity, and little related with the protection gas velocity in free jet. In hindered jet, powder concentration obviously increases with the powder feeding rate, obviously decreases with the carrier gas velocity, and little related with the protection gas velocity, besides, the concentration position slightly moves upon compared with that of free jet. Powder concentration obviously increases with the increase of cladding width while the concentration position keeps still; the increase of cladding height makes little effect on powder concentration.