激光沉积制造同轴送粉喷嘴纵吹气帘对粉末汇聚性的影响
发布时间：2018-10-05 16:08
【摘要】：在激光沉积制造时,粉末汇聚性是保证成形质量的关键因素。为了改善粉末的汇聚性,采用气固两相流理论对载气式同轴送粉喷嘴纵吹气帘气压力大小对粉末汇聚性影响进行了数值模拟,应用FLUENT软件中的离散相模型计算了粉末流场速度和浓度分布规律及汇聚特性。模拟结果表明,纵吹气压力较小(0.3 MPa)时会导致粉末流充满整个流场域,汇聚性极差;气压力较大(0.7MPa)时同样粉末汇聚性较差,影响沉积制造成形质量;气压力为0.5MPa时汇聚性良好,且在焦点到焦点以下10mm的汇聚区进行激光沉积制造能形成较好的熔池,成形质量较好同时提高了粉末利用率。试验结果验证了模拟结果的合理性,数值模拟结果对同轴送粉喷嘴设计和结构优化具有较大的参考价值,并解决了现有喷嘴粉末汇聚性较差问题。
[Abstract]:In laser deposition, powder aggregation is the key factor to ensure the forming quality. In order to improve the convergency of the powder, the effect of the pressure of the gas curtain on the convergency of the powder was simulated by using the gas-solid two-phase flow theory. The velocity and concentration distribution and convergence characteristics of powder flow field were calculated by using the discrete phase model in FLUENT software. The simulation results show that when the longitudinal blowing pressure is small (0.3 MPa), the powder flow will fill the whole flow field, and the convergence is extremely poor, and when the gas pressure is high (0.7MPa), the powder aggregation is also poor, which affects the quality of deposition manufacturing, and when the gas pressure is 0.5MPa, the aggregation is good. In addition, laser deposition in the convergent region of 10mm from focus to focus can form a better molten pool, and the forming quality is better and the powder utilization ratio is improved. The experimental results verify the rationality of the simulation results. The numerical simulation results have great reference value for the design and structure optimization of coaxial powder feeding nozzles, and solve the problem of poor powder convergence of existing nozzles.
【作者单位】： 沈阳航空航天大学航空制造工艺数字化国防重点学科实验室;
【基金】：科技重大专项资助项目(项目编号:2013ZX04001-041-04)
【分类号】：TN249
本文编号：2254022
[Abstract]:In laser deposition, powder aggregation is the key factor to ensure the forming quality. In order to improve the convergency of the powder, the effect of the pressure of the gas curtain on the convergency of the powder was simulated by using the gas-solid two-phase flow theory. The velocity and concentration distribution and convergence characteristics of powder flow field were calculated by using the discrete phase model in FLUENT software. The simulation results show that when the longitudinal blowing pressure is small (0.3 MPa), the powder flow will fill the whole flow field, and the convergence is extremely poor, and when the gas pressure is high (0.7MPa), the powder aggregation is also poor, which affects the quality of deposition manufacturing, and when the gas pressure is 0.5MPa, the aggregation is good. In addition, laser deposition in the convergent region of 10mm from focus to focus can form a better molten pool, and the forming quality is better and the powder utilization ratio is improved. The experimental results verify the rationality of the simulation results. The numerical simulation results have great reference value for the design and structure optimization of coaxial powder feeding nozzles, and solve the problem of poor powder convergence of existing nozzles.
【作者单位】： 沈阳航空航天大学航空制造工艺数字化国防重点学科实验室;
【基金】：科技重大专项资助项目(项目编号:2013ZX04001-041-04)
【分类号】：TN249
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