Lee Young Ki, Ahn Kyung Hyun, Lee Seung Jong
School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Seoul, 151-744 Korea.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Dec;90(6):062317. doi: 10.1103/PhysRevE.90.062317. Epub 2014 Dec 29.
The local shear stress of non-Brownian suspensions was investigated using the lattice Boltzmann method coupled with the smoothed profile method. Previous studies have only focused on the bulk rheology of complex fluids because the local rheology of complex fluids was not accessible due to technical limitations. In this study, the local shear stress of two-dimensional solid particle suspensions in Couette flow was investigated with the method of planes to correlate non-Newtonian fluid behavior with the structural evolution of concentrated particle suspensions. Shear thickening was successfully captured for highly concentrated suspensions at high particle Reynolds number, and both the local rheology and local structure of the suspensions were analyzed. It was also found that the linear correlation between the local particle stress and local particle volume fraction was dramatically reduced during shear thickening. These results clearly show how the change in local structure of suspensions influences the local and bulk rheology of the suspensions.
采用格子玻尔兹曼方法结合平滑剖面法研究了非布朗悬浮液的局部剪切应力。以往的研究仅关注复杂流体的整体流变学，因为由于技术限制，复杂流体的局部流变学难以获取。在本研究中，采用平面法研究了二维固体颗粒悬浮液在库埃特流中的局部剪切应力，以关联非牛顿流体行为与浓颗粒悬浮液的结构演变。在高颗粒雷诺数下，成功捕捉到了高浓度悬浮液的剪切增稠现象，并对悬浮液的局部流变学和局部结构进行了分析。研究还发现，在剪切增稠过程中，局部颗粒应力与局部颗粒体积分数之间的线性相关性显著降低。这些结果清楚地表明了悬浮液局部结构的变化如何影响悬浮液的局部和整体流变学。
