论文标题
理想的导电粒子的零剪切率限制流变行为，悬浮在电场下的浓缩分散体中
The zero-shear-rate limiting rheological behaviors of ideally conductive particles suspended in concentrated dispersions under an electric field
论文作者
论文摘要
使用大规模的数值模拟在零剪切率流量的极限中研究了理想导电颗粒悬浮液的流变行为。在电场的作用下，颗粒经历了被称为二型溶菌的非线性电动现象，这是介电粒细胞和诱导电泳的组合。对于理想的导电颗粒，悬浮液的动力学主要由诱导的电泳电泳控制。为了表征悬浮液的流变特性，粒子应力张量和粒子压力是在数量分数中计算出的，直到几乎随机的关闭堆积。粒子正常应力和粒子压力显示出具有体积分数的非单调性，尤其是在浓缩方案中。特别是，粒子压力的体积分数为阳性，最高为30 \％，之后变为负，表明粒子压力的性质发生了变化。还评估了由配对分布函数和悬架熵表达的微观结构。局部微观结构的可见变化似乎与粒子正常应力和颗粒压力的非单调变化相关。这些非单调行为也与我们最近的研究中观察到的粒子配对动力学的主要机理的变化相关[Mirfendereski \＆Park，J。Fluid Mech。 \ textbf {875}，r3（2019）]。最后，研究了限制对颗粒应力和颗粒压力的影响。发现随着限制水平的增加，粒子压力在高体积分数下很快就会改变其性质。这项研究应激发控制策略，以充分利用这种悬浮系统的流变性操纵压力的明显变化性质。
The rheological behaviors of suspension of ideally conductive particles in an electric field are studied using large-scale numerical simulations in the limit of zero-shear-rate flow. Under the action of an electric field, the particles undergo the nonlinear electrokinetic phenomenon termed as dipolophoresis, which is the combination of dielectrophoresis and induced-charge electrophoresis. For ideally conductive particles, the dynamics of the suspension are primarily controlled by induced-charge electrophoresis. To characterize the rheological properties of the suspension, the particle stress tensor and particle pressure are calculated in a range of volume fraction up to almost random close packing. The particle normal stress and particle pressure are shown to behave non-monotonically with volume fraction, especially in concentrated regimes. In particular, the particle pressure is positive for volume fraction up to 30\%, after which it becomes negative, indicating a change in the nature of the particle pressure. The microstructure expressed by pair distribution function and suspension entropy is also evaluated. Visible variations in the local microstructure seem to correlate with the non-monotonic variation in the particle normal stresses and particle pressure. These non-monotonic behaviors are also correlated with the change in the dominant mechanism of particle pairing dynamics observed in our recent study [Mirfendereski \& Park, J. Fluid Mech. \textbf{875}, R3 (2019)]. Lastly, the effects of confinement on the particle stress and particle pressure are investigated. It is found that the particle pressure changes its nature very quickly at high volume fractions as the level of confinement increases. This study should motivate control strategies to fully exploit the distinct changing nature of the pressure for rheological manipulation of such suspension system.
