挤出式3D打印陶瓷梯度材料动态混合过程数值模拟  

Numerical Simulation of a Dynamic Mixing Process of Ceramic-Grade Materials for Extruded 3D Printing

作　　者：段国林[1] 王龙 王世杰 马硕 杨杰[1] 韩晓伟 Duan Guolin;Wang Long;Wang Shijie;Ma Shuo;Yang Jie;Han Xiaowei(School of Mechanical Engineering,Hebei University of Technology,Tianjin 300401,China)

机构地区：[1]河北工业大学机械工程学院,天津300401

出　　处：《天津大学学报（自然科学与工程技术版）》2023年第12期1264-1276,共13页Journal of Tianjin University：Science and Technology

基　　金：中央引导地方科技发展资金资助项目(216Z1804G)。

摘　　要：针对微流挤出工艺下制备陶瓷梯度材料引起的混合难题,依托混合挤出核心功能部件——多组分主动混合机构,结合理论分析、ANSYS仿真模拟与打印实验,探究了螺杆结构下混料腔内多组分材料混合机制及其规律.首先,对流体流动进行理论分析;其次,对料腔内流体流场进行仿真分析,定义了该工艺下材料混合时间的构成;最后以螺杆转速、材料进给量、进料顺序3个影响因素作为研究对象,通过组分输运模型进行模拟分析,研究了上述3个因素对多材料混合过程的影响及其规律.结果表明:在变径螺杆作用下腔内压力沿着挤出方向阶跃式升高,口模附近迅速泄压;腔内流体速度沿挤出方向递增,在螺槽的左、右底角部位会形成材料滞留区.螺杆转速的变化对内部流体的流动影响大于进给量;通过混合过程模拟结果发现螺杆转速的增加有利于提高平面混合均匀性,对腔内流体的平均停留时间影响不大;增大进料量不仅缩短了混料腔内流体停留时间,还降低了螺杆的轴向混合能力;材料过渡时间随着料腔内高黏度流体体积分数的增加而逐渐增加.最后,打印锯齿形梯度渐变部件,利用MATLAB软件进行图像处理,验证了理论分析与数值模拟研究的合理性与正确性.该研究为了解挤出式3D打印陶瓷梯度材料混合过程的机理奠定了基础,并为后续混料设备的结构改进提供了理论支持.This study aims to address mixing challenges in the preparation of ceramic-grade materials in the microflow extrusion process.Based on the multicomponent active mixing mechanism,the core component of mixing and extrusion,theoretical analysis,ANSYS simulation,and printing experiments were all performed to investigate the multicomponent materials mixing mechanism and its laws in the mixing cavity under the screw core component.First,a theoretical analysis of the fluid flow was conducted,and a simulation of the fluid flow field in the material cavity was developed to define the construction of the material mixing time under the mixing process.Moreover,three influencing factors,namely,screw speed,material feed rate,and feeding sequence,were considered the object of study.A component transport model simulation was conducted to investigate the influence of these three factors on the multimaterial mixing process and their laws.The results indicate that the cavity pressure rises stepwise in the extrusion direction under the variable diameter screw,and the pressure near the die is rapidly relieved.The velocity of the fluid inside the cavity increases in the extrusion direction,and a material stagnation zone is formed at the left and right bottom corners of the screw groove.The change in screw speed has a greater impact on the internal fluid flow than that in the feed rate.By conducting mixing process simulations,an increase in screw speed is found beneficial for improving the homogeneity of planar mixing and has little effect on the average residence time of the fluid in the cavity.Specifically,increasing the feed rate shortens the fluid residence time in the mixing cavity and reduces the axial mixing capacity of the screw.With increasing volume fraction of the high viscosity fluid in the cavity,the material transition time gradually increases.Furthermore,sawtooth-shaped graded parts were 3D printed,and image processing using MATLAB software was used to verify the rationality and correctness of the theoretical analysis an

关 键 词：微流挤出 陶瓷梯度材料 多组分材料混合 混合时间 混合过程模拟 

分 类 号：TH145.1[一般工业技术—材料科学与工程] TP399[机械工程—机械制造及自动化]