Simulating the rheology of dense colloidal suspensions using dissipative particle dynamics
Simulating the rheology of dense colloidal suspensions using dissipative particle dynamics
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DOI：
10.1103/physreve.55.3124
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发表时间：
1997-03-01
影响因子：
2.4
通讯作者：
vanderSchoot, P
中科院分区：
文献类型：
--
作者：
Boek, ES;Coveney, PV;vanderSchoot, P
用介观模拟技术，即耗散粒子动力学（DPD），研究了球、棒和盘的胶体悬浮液的流变特性。在DPD中，悬浮液被建模为相互作用的点粒子的液体中的大胶体粒子的系统。对于流体动力学相互作用的计算，该方法比使用溶剂的连续模型的常规技术在计算上更有效。对颗粒悬浮液施加稳态剪切速率，测量了粘度随剪切速率和悬浮颗粒体积分数的变化。30体积%的球体悬浮液的粘度显示出作为增加剪切速率的函数的特征剪切稀化行为。高剪切粘度和低剪切粘度的值与实验数据吻合得很好。对于较高的颗粒密度，获得良好的结果为高剪切粘度，虽然在低剪切速率下的粘度显示依赖于悬浮球的大小，我们归因于有限的尺寸效应。稀悬浮液的棒和磁盘显示特性粘度是在极好的协议与理论预测。对于棒和盘的浓悬浮液，粘度随体积分数的三次方增加。我们发现了与Doi和Edwards [M. Doi和S. F. Edwards，The Theory of Polymer Dynamics（Oxford University Press，纽约，1986）]，用于半稀释状态下的棒悬浮。DPD模拟技术是研究颗粒悬浮液流变性阿萨有效工具。
The rheological properties of colloidal suspensions of spheres, rods, and disks have been studied using a mesoscopic simulation technique, known as dissipative particle dynamics (DPD). In DPD, a suspension is modeled as a system of large colloidal particles in a liquid of interacting point particles. For the calculation of hydrodynamic interactions, this method is computationally more efficient than conventional techniques using a continuum model for the solvent. Applying a steady-shear rate to the particulate suspensions, we have measured the viscosity as a function of shear rate and volume fraction of the suspended particles. The viscosity of a 30 vol % suspension of spheres displays characteristic shear-thinning behavior as a function of increasing shear rate. The values for the high- and low-shear viscosity are in good agreement with experimental data. For higher particulate densities good results are obtained for the high-shear viscosity, although the viscosity at low-shear rates shows a dependence on the size of the suspended spheres that we attribute to finite size effects. Dilute suspensions of rods and disks show intrinsic viscosities which are in excellent agreement with theoretical predictions. For concentrated suspensions of both rods and disks, the viscosity increases with the third power of the volume fraction. We find the same scaling behavior as predicted by Doi and Edwards [M. Doi and S. F. Edwards, The Theory of Polymer Dynamics (Oxford University Press, New York, 1986)] for rod suspensions in the semidilute regime. The DPD simulation technique emerges asa useful tool for studying the rheology of particulate suspensions.