Analog of discontinuous shear thickening flows under confining pressure
Analog of discontinuous shear thickening flows under confining pressure
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围压下不连续剪切增稠流的模拟
DOI：
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发表时间：
2017
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通讯作者：
M. Trulsson
中科院分区：
文献类型：
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作者：
Junhao Dong;M. Trulsson
我们使用二维数值模拟研究稠密悬浮液的非布朗硬颗粒使用临界负荷模型（CLM）在恒定的围压。在恒定的填充分数，这个简单的模型显示剪切增稠的切向力得到激活后，增加剪切应力。通过参数化一个简单的二元系统的摩擦和非摩擦颗粒的不同比例，我们表明，堵塞包装分数，在粘度发散，控制摩擦接触的分数。因此，稠密悬浮液的粘度可以表示为摩擦接触分数以及固体颗粒的堆积分数的函数。此外，我们表明，摩擦接触的分数和两个控制参数（围压下）之间存在一个简单的关系：粘性数J和排斥力和围压之间的比率。在围压下的粘度曲线被发现依赖于剪切协议，产生负的动态压缩性的可能性，类似于不连续的剪切增稠发现在高，但恒定的包装分数为同一系统。（减）
We use two-dimensional numerical simulations to study dense suspensions of non-Brownian hard particles using the Critical Load Model (CLM) under constant confining pressures. At constant packing fraction this simple model shows shear thickening as the tangential forces get activated upon increased shear stresses. By parameterizing a simple binary system of frictional and nonfrictional particles of different proportions we show that the jamming packing fraction, at which the viscosity diverges, is controlled by the fraction of frictional contacts. The viscosity of dense suspensions can thereby be expressed as a function of the fraction of frictional contacts as well as the packing fraction of solid particles. In addition, we show that there exists a simple relationship between the fraction of frictional contacts and the two control parameters (under confining pressure): the viscous number J and the ratio between the repulsive barrier force and confining pressure. Under confining pressures the viscosity curves are found to depend on the shear protocol, with the possibility of yielding negative dynamic compressibility, an analog to the discontinous shear thickening found at high but constant packing fractions for the same system. (Less)