金属粉末注射充填中渗流现象的数值仿真  

Numerical Simulation of Seepage Phenomenon in Metal Powder Injection Filling

作　　者：裔英明 丁桦 YI Yingming;DING Hua(Guangzhou Institute of Industrial Technology,Guangzhou 511458,China)

机构地区：[1]广州工业技术研究院,广州511458

出　　处：《材料导报》2022年第S02期426-431,共6页Materials Reports

摘　　要：在金属粉末注射充填中,金属粉末相与粘结剂相会发生两相偏析。在高粉末体积分数处当金属粉末相流速为零时粘结剂相会发生渗流。目前已有采用两相流体数学模型对偏析的仿真研究,尚未有对渗流的仿真。使用两相流体数学模型时在粉末相流速为零处粘结剂相流速满足达西定律,即该模型亦适用于渗流的仿真。然而,目前在使用该模型时为简化计算认为粉末相粘度和动量交换系数在高、低粉末体积分数处相同。这种简化虽然可模拟出发生在低粉末体积分数处的偏析现象,但是导致高粉末体积分数处渗流发生时强烈的粉末相内部相互作用和两相间相互作用不能得到准确模拟,从而不能对渗流进行仿真。本工作提出了将粉末相粘度与动量交换系数模型化以模拟渗流的方法。使用该方法对收缩矩形管道内的注射充填进行仿真,结果显示收缩管道中收缩处金属粉末发生了聚集,粘结剂产生了渗流,并且渗流的发生使得粉末体积分数产生较大的不均匀分布。本工作中的方法可为其他领域的多相流中渗流形成的研究提供参考。In metal powder injection filling,the separation between metal powder phase and binder phase occurs.And the seepage occurs when the velocity of the metal powder phase is zero at the regions of high volume fraction of powder.In the previous researches,the separation has been simulated by adopting the two-phase fluid mathematical model.However,the seepage phenomenon has not been simulated.When the twophase fluid mathematical model is used,the velocity of the binder phase satisfies the Darcy’s law at the regions where the velocity of the metal powder phase is zero.It means that the model can be used for the simulation of the seepage phenomenon.However,in the previous studies,in order to simplify the computation,the viscosity of the powder phase and the momentum exchange coefficient between the two phases were considered to be the same at the regions of high and low volume fraction of powder.By simplifying,the separation at the regions of low volume fraction of powder was simulated.However,the strong interaction within the powder phase and the strong interaction between the two phases when the seepage occurs at the regions of high volume fraction of powder can not be accurately simulated by the simplified model,and thus the seepage phenomenon can not be simulated.In this work,a method is proposed to simulate the seepage phenomenon by modelling the viscosity of the powder phase and modelling the momentum exchange coefficient.The injection filling in the contracted rectangular pipe is simulated by using the proposed method.The results show that the metal powder gathers and the seepage of the binder phase occurs in the contraction region of the contracted pipe.It can also be found that the seepage phenomenon causes high variation of the distribution of the volume fraction of powder.The proposed method in this work can provide a reference for the study of the formation of the seepage phenomenon in multiphase flows of other research fields.

关 键 词：金属粉末注射成型 注射充填 渗流 粘度模型 动量交换系数模型 有限单元法 

分 类 号：O35[理学—流体力学]