气体雾化制粉工艺中基于气体整流的卫星粉控制技术  

Satellite-particle control technique based on gas-flow-regulation during gas atomization process

作　　者：赫新宇 黎兴刚 黄禹赫 朱强 HE Xin-yu;LI Xing-gang;Huang Yu-he;ZHU Qiang(Department of Mechanical and Energy Engineering,Southern University of Science and Technology,Shenzhen,518055,China;Academy for Advanced Interdisciplinary Studies,Southern University of Science and Technology,Shenzhen,518055,China)

机构地区：[1]南方科技大学机械与能源工程系,深圳518055 [2]南方科技大学前沿与交叉科学研究院,深圳518055

出　　处：《粉末冶金技术》2022年第4期302-317,共16页Powder Metallurgy Technology

基　　金：国家自然科学基金资助项目(52074157);深圳市基础研究项目(JCYJ20210324104608023);深圳市技术攻关项目(JSGG20180508152608855);深圳市高机能材料增材制造重点实验室项目(ZDSYS201703031748354)。

摘　　要：金属熔体气体雾化法是制备增材制造专用金属粉末的重要方法。然而,气体雾化工艺制得的粉末中通常混有大量卫星粉,对金属增材制造工艺产生不利影响。本文通过施加辅助气流并采用阶梯状雾化室结构等气体整流措施抑制回流区中的粉尘回旋,进而控制卫星粉的形成。利用计算流体力学软件ANSYS Fluent进行数值模拟,研究施加辅助气流或采用阶梯状雾化室结构时,雾化室内宏观流场特征以及颗粒运动轨迹的变化规律。结果表明,在雾化室顶部距雾化室中心R/2(R为雾化室半径)处施加辅雾比(辅助气流与雾化气流的流量比)大于0.8的辅助气流时能够有效抑制回流区中的粉尘回旋;采用阶梯宽为300 mm、高为575~600 mm的雾化室结构能够有效抑制回流区中的粉尘回旋。根据数值模拟结果,采用气体整流措施制备TC4钛合金粉末,并检测粉末的粒径分布、球形度、赘生物指数等指标,发现与不采用气体整流措施制备的粉末相比,赘生物指数降低约45%。Gas atomization(GA)is an essential method for the preparation of metal powders specifically used in the additive manufacturing.However,there are plenty of“satellites”among the metal powders prepared by GA.The existence of these satellite particles negatively affects the metal additive manufacturing process.In this paper,two gas-flow-regulation strategies,i.e.,the introduction of ancillary gas flow and the design of step-shape atomization chamber,were employed to prevent the fine particle entrainment in gas recirculation zone,thus restricting the formation of satellite particles.The evolution of macro flow patterns and particle trajectories were studied based on the numerical simulation by the commercial computational fluid dynamics software ANSYS Fluent.The results show that,the fine particle entrainment in gas recirculation zone can be effectively prevented when the ancillary gas flow is introduced at the position of R/2(R is the radius of atomization chamber)away from the chamber center with the AAR(the ratio of ancillary flow rate to atomization flow rate)larger than 0.8,or when a step-shaped atomization chamber is employed with a step width of 300 mm and a step height of around 575~600 mm,respectively.Some TC4 titanium alloy powders were prepared by applying the above gas-flow-regulation strategies while their size distribution,sphericity and outgrowth rate were characterized,respectively.The results show that,the outgrowth rate of the powders has been reduced by about 45%,compared with those prepared without the gas-flow-regulation strategies.

关 键 词：气体雾化 卫星粉 计算流体力学 气体整流 赘生物指数 

分 类 号：TF123.1[冶金工程—粉末冶金]