激光选区熔化的风场仿真与流道结构优化

针对激光选区熔化的黑烟残留问题，基于E-Plus-M250激光选区熔化成形设备，运用ANSYS ICEM CFD、ANSYS FLUENT等软件对保护气供气流道截面与成形仓黑烟产生区域的截面进行仿真模拟，并根据仿真结果对保护气供气流道进行结构优化。结果表明成形仓粉床面的黑烟残留问题是由激光扫描区域风场分布不均匀造成的。对供气流道结构进行多次改进优化与流场仿真，结果表明，理论上可将进风口截面风速分布标准差值从0.472 7降低至0.182 1。实验验证了优化方案的有效性，采用优化后的流道结构能更有效地去除成形仓中激光熔化金属粉末时产生的黑烟。

Gas Field Simulation and Flow Channel Structure Optimization of SLM

Aiming at the black smoke residue phenomenon during SLM processes, the gas field in the cross sections of inert gas supply channels and the black smoke generation zones in the forming chambers of a SLM system called E-Plus-M250 were simulated using ANSYS ICEM CFD and ANSYS FLUENT. The structures of the inert gas supply channels were optimized based on the simulation results. The simulation results show that the residual black smoke on the powder beds of the forming chambers is caused by the uneven distribution of the gas field in the laser scanning areas. Based on the simulation results and through sever improvements to the structures of the gas supply channels, the standard deviation of the air velocity distribution at the air inlet cross sections is reduced from 0.472 7 to 0.182 1, which is in good agreement with the flow fields of the forming chambers. The experiments verify the effectiveness of the optimization scheme, which means that the optimized flow channel has the capability of removing the black smoke more effectively when the metal powder is melted in the forming chambers.