粉末注射成形喂料的流体动力学

A hydrodynamic theory for feedstock in powder injection molding

本文通过合并近年来报道的高聚物和颗粒物质的流体力学理论,提出了一个描述其混合物—粉末注射成形喂料宏观力学行为的新理论.与传统的喂料非牛顿流体力学相比,该理论多出了颗粒温度和两个弹性应变张量(分别表征高聚物和颗粒物组元)等状态变量,能全面描述喂料中出现的颗粒骨架和高聚物的弹性效应.对平面定常剪切流动情形,它简化为表观剪切黏度性质与喂料一致的非牛顿流体力学方程,表明新理论包含了传统喂料理论,因此可用于研究其适用前提,和包括法向应力差系数在内的流变学参数.本工作除有助于研究复杂多相系统连续力学方程的建立方法外,还将对粉末注射成形领域关注的喂料动力学分析提供一条新途径.

By combining two hydrodynamic theories of polymer and granular matter reported recently,we proposed a theory describing macroscopic mechanical behaviors of feedstock in powder injection molding.In contrast with the traditional non-Newtonian hydrodynamics of feedstock,the theory has as state variables in addition a granular temperature and two tensors of elastic strain（for polymer and granular components respectively）,then can give a complete description of elastic effects due to granular skeleton and polymer.In a special case of steady planar shear ？ow,it is reduced to the non-Newtonian hydrodynamics with an apparent viscosity comparable to those measured for feedstock.This supports that the new theory does contain the traditional one,so can be used to study its validity range,and the rheological parameters including coefficients of differences of normal stresses.The work provides a new way for analyzing feedstock dynamics interested in powder injection molding.Also its method is helpful for establishing continuos mechanical equations of other multi-phase systems.