Xu Bu, Gilchrist James F
Department of Chemical Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
J Chem Phys. 2014 May 28;140(20):204903. doi: 10.1063/1.4875589.
Hydrodynamic and near-particle interactions in sheared suspensions are communicated through suspension microstructure to produce a wide variety of rheological behaviors. To characterize this microstructure, the individual positions of monosized silica particles flowing through a microchannel are obtained with near simulation-level detail. The pair distribution functions of the microstructure at moderate to high Péclet number shear rates are very similar to previous numerical studies. Viscometric functions calculated based on the detailed microstructure obtained through this technique show qualitative agreement with computational results. These results elucidate the origins of shear-thickening of suspensions at high shear rates. While efforts are taken to screen electrostatic interactions to study hydrodynamic and Brownian interactions, the role of electrostatic interaction between particles is also investigated by reducing suspension ionic strength. These non-hydrodynamic electrostatic interactions result in a loss of anisotropy that generally agrees with previous findings of "soft" particle systems.
剪切悬浮液中的流体动力学和近颗粒相互作用通过悬浮液微观结构进行传递，从而产生各种各样的流变行为。为了表征这种微观结构，以接近模拟级别的细节获取了流经微通道的单尺寸二氧化硅颗粒的个体位置。在中等到高佩克莱数剪切速率下微观结构的对分布函数与先前的数值研究非常相似。基于通过该技术获得的详细微观结构计算出的粘度函数与计算结果显示出定性的一致性。这些结果阐明了悬浮液在高剪切速率下剪切增稠的起源。在努力屏蔽静电相互作用以研究流体动力学和布朗相互作用的同时，还通过降低悬浮液离子强度来研究颗粒间静电相互作用的作用。这些非流体动力学的静电相互作用导致各向异性的丧失，这与先前“软”颗粒系统的研究结果总体一致。
