Impact of Novel Nozzles on Atomization Flow Field and Particle Features: Simulation and Experimental Validation

Gas-atomized powder characteristics significantly impact additive manufacturing processes. Two innovative nozzles, semi-converging–diverging nozzle type II and fully converging–diverging nozzle type III, were designed based on the traditional cylindrical nozzle type I. Utilizing the k-ε model and Discrete Phase Model (DPM), the flow field evolution and powder characteristics of these nozzles were analyzed at gas pressures ranging from 4 to 8 MPa. The results indicate that in the gas-phase flow field both nozzle type II and nozzle type III can achieve a performance comparable to that of nozzle type I at significantly lower gas pressures. Specifically, nozzle type II operates effectively with a reduction of approximately 1 MPa compared to nozzle type I, while nozzle type III demonstrates an even greater advantage with a pressure reduction of about 2 MPa. In the gas–melt-phase flow field, nozzle type III still has the effect of reducing the pressure by approximately 2 MPa compared to nozzle type I. The melt fracture process under nozzle type III is divided into three distinct stages: the formation of large droplets, a transition area for fragmentation, and a fully fragmented region. This research effectively reduces energy losses and offers novel insights as well as recommendations for applications related to atomization technology.