The rheology of suspensions of solid particles
The rheology of suspensions of solid particles
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DOI：
10.1098/rspa.2009.0445
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发表时间：
2010-04-08
影响因子：
3.5
通讯作者：
Mader, H. M.
中科院分区：
文献类型：
--
作者：
Mueller, S.;Llewellin, E. W.;Mader, H. M.
我们目前的数据为不同的纵横比，从扁长到扁长的单分散颗粒的悬浮液的流变学，并覆盖颗粒体积分数φ从稀到高度浓缩。流变学的特点是。将实验数据拟合到Herschel & Bulkley（Herschel & Bulkley 1926 Kolloid Z. 39，291-300（doi：10.1007/BF 01432034）），得到三个流变参数：稠度K（与粘度同源）;流动指数n（剪切稀化的量度）;屈服应力τ（0）。任意纵横比的颗粒的悬浮液的稠度K可以通过Maron & Pierce的模型（Maron & Pierce 1956 J. Colloid Sci. 11，80-95（doi：10.1016/0095-8522（56）90023-X）），其中最大填充分数phi（m）作为唯一的拟合参数。我们推导出经验关系式，φ（m）和n作为平均颗粒纵横比r（p）的函数，τ（0）作为fm和拟合参数τ * 的函数。这些关系可以用来预测由测量的φ和r（p）的扁长颗粒悬浮液的流变学。通过根据爱因斯坦系数重铸我们的数据，我们将我们的流变学观测与基础粒子运动通过Jeffery的（Jeffery 1922 Proc. R. Soc. Lond. A 102，161-179（doi：10.1098/rspa. 1922.0078））理论。我们扩展杰弗里的工作，计算，数值，爱因斯坦系数的悬浮液中的许多，最初随机取向的粒子。这提供了一个物理的，微观结构的解释，我们的观察，包括瞬态振荡过程中看到的运行启动和流变制度的变化，φ增加。
We present data for the rheology of suspensions of monodisperse particles of varying aspect ratio, from oblate to prolate, and covering particle volume fractions phi from dilute to highly concentrated. Rheology is characterized by. tting the experimental data to the model of Herschel & Bulkley (Herschel & Bulkley 1926 Kolloid Z. 39, 291-300 (doi: 10.1007/BF01432034)) yielding three rheometric parameters: consistency K (cognate with viscosity); flow index n (a measure of shear-thinning); yield stress tau(0). The consistency K of suspensions of particles of arbitrary aspect ratio can be accurately predicted by the model of Maron & Pierce (Maron & Pierce 1956 J. Colloid Sci. 11, 80-95 (doi: 10.1016/0095-8522(56)90023-X)) with the maximum packing fraction phi(m) as the only fitted parameter. We derive empirical relationships for phi(m) and n as a function of average particle aspect ratio r(p) and for tau(0) as a function of fm and a fitting parameter tau*. These relationships can be used to predict the rheology of suspensions of prolate particles from measured phi and r(p). By recasting our data in terms of the Einstein coefficient, we relate our rheological observations to the underlying particle motions via Jeffery's (Jeffery 1922 Proc. R. Soc. Lond. A 102, 161-179 (doi: 10.1098/rspa. 1922.0078)) theory. We extend Jeffery's work to calculate, numerically, the Einstein coefficient for a suspension of many, initially randomly oriented particles. This provides a physical, microstructural explanation of our observations, including transient oscillations seen during run start-up and changes of rheological regime as phi increases.