摘要
异质材料零件具有均质材料不具备的众多优异特性,广泛应用于航空航天等重大装备、特殊服役环境零件的制造。送粉系统是异质材料零件激光近净成形的关键器件,其性能决定成形零件的质量。为此,设计面向异质材料激光近净成形同轴送粉系统,利用离散模型对送粉喷嘴流场进行数值模拟,通过对喷嘴平面下方颗粒运动轨迹和粉末浓度分布的数值模拟,获得理想的送粉喷嘴模型(内部载气和外部保护气共同作用的同轴送粉方式)。为进一步验证该结论,针对于不同送粉方式的不同流道倾角进行数值分析,确定了满足条件的流道倾角范围,获得了基体距离喷嘴口平面的距离范围,之后,针对异质材料粉末混合比例的不同,通过变换混合材料密度得出不同阶段的汇聚效果图及喷嘴下方汇聚区域的混合粉末浓度变化曲线,计算得出不同阶段粉末利用率变化曲线,结果表明:送粉系统能够实现不同比例粉末在不同路径间快速、准确切换,保证成形过程的连续性,从而提高零件性能和工作效率,且粉末利用率达到42.50%以上,实现理想的送粉效果。
Heterogeneous parts have many excellent characteristics that are not possessed by homogeneous materials, and are widely used in the manufacturing of major equipment in the field of aerospace and other facilities in special service. The powder-feeding system is the key component for laser near-net forming of heterogeneous parts, and its performance determines the quality of the formed parts. To this end, in this article the coaxial powder-feeding system of laser near-net forming for heterogeneous materials is designed. The discrete model is applied to numerically simulate the powder-feeding nozzle’s flow field;the ideal model of the powder-feeding nozzle is worked out by means of numerical simulation of the particle’s motion trajectory and powder concentration distribution below the nozzle plane(the coaxial powder-feeding method through which internal carrier gas and external shielding gas work together). In order to further verify this conclusion, numerical analysis is carried out on the inclination angles of different flow channels when various powder-feeding methods are applied;the required range of the channel inclination angle is worked out, and the distance range of the base body from the nozzle plane is obtained. Then, according to the difference of the mixing ratio of the heterogeneous powder, the convergence effect of the mixed material and the concentration curve of the mixed powder in the confluent area below the nozzle are identified by changing the density of the mixed material, and the curve of powder utilization in different stages is calculated. These results show that the powder-feeding system can realize fast and accurate switching of powder with different proportions between different paths. As a result, the continuity of the molding process is ensured;the parts enjoy higher performance and working efficiency. The rate of powder utilization is above 42.50%, which has achieved the ideal powder-feeding effect.
作者
张争艳
雷焱阳
王顺
杨雪慧
孙立新
ZHANG Zheng-yan;LEI Yan-yang;WANG Shun;YANG Xue-hui;SUN Li-xin(School of Mechanical Engineering,Hebei Technology of University,Tianjin 300130)
出处
《机械设计》
CSCD
北大核心
2021年第11期57-66,共10页
Journal of Machine Design
基金
国家自然科学基金(61802108)
河北省自然科学基金(E2017202296)。
关键词
激光近净成形
数值分析
送粉方式
流道倾角
粉末浓度
laser near-net forming
numerical analysis
way of feeding
port angle
powder concentration
作者简介
张争艳(1984-),男,副教授,博士,研究方向:3D打印。E-mail:zzy@hebut.edu.cn;通信作者:孙立新(1964—),男,教授,博士,研究方向:机电一体化。E-mail:sunlixin100@126.com。
