Xia Bin, Krueger Paul S
Department of Mechanical Engineering, Southern Methodist University, Dallas, TX 75205, USA.
Proc Math Phys Eng Sci. 2022 Jun;478(2262):20210615. doi: 10.1098/rspa.2021.0615. Epub 2022 Jun 15.
Particulate suspensions occur in situations from blood flow to slurries in drilling applications. Existing investigations of these suspensions generally concentrate on the impact of particle volume fraction for suspensions in Newtonian fluids under free-flow conditions. Recently, particulate-polymer composites have been used in additive manufacturing (AM). Here, the polymer becomes a shear-thinning non-Newtonian fluid during extrusion, creating a particulate suspension. Motivated by the challenges in AM of particulate composites, this study investigates the rheology of suspensions of micrometre-sized particles in shear-thinning silicone while extruded through AM-scaled nozzles (millimetre-scale diameters). The suspensions were observed to follow a power-law behaviour and their rheology was investigated through the measured flow consistency ( ) and behaviour ( ) indices. The impact of the particle volume fraction ( ) and the ratio ( ) of the capillary inside diameter to the particle diameter on both indices were measured. was found to be only impacted by the suspension fluid type and . was found to be constant at large , but decreased and then increased to infinity with decreasing. Based on its behaviour, was categorized into two conditions and analysed separately with semi-empirical models. The impact of particle size distribution was also investigated.
颗粒悬浮液存在于从血液流动到钻井应用中的泥浆等各种情况中。现有的对这些悬浮液的研究通常集中在自由流动条件下牛顿流体中颗粒体积分数的影响。最近，颗粒 - 聚合物复合材料已被用于增材制造（AM）。在这里，聚合物在挤出过程中变成一种剪切变稀的非牛顿流体，形成颗粒悬浮液。受颗粒复合材料增材制造中挑战的推动，本研究调查了微米级颗粒在通过增材制造规模的喷嘴（毫米级直径）挤出时在剪切变稀硅酮中的悬浮液流变学。观察到悬浮液遵循幂律行为，并通过测量的流动一致性（ ）和行为（ ）指数来研究其流变学。测量了颗粒体积分数（ ）以及毛细管内径与颗粒直径之比（ ）对这两个指数的影响。发现 仅受悬浮液流体类型和 的影响。发现 在大的 时是恒定的，但随着 减小而先减小然后增加到无穷大。基于其行为， 被分为两种情况并用半经验模型分别进行分析。还研究了粒度分布的影响。
