Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden.
Langmuir. 2010 Dec 21;26(24):18701-9. doi: 10.1021/la103537y. Epub 2010 Nov 23.
High-energy angle-dispersive X-ray diffraction has been used to study the alignment of colloidal suspension of kaolinite particles in water as they flow along a pipe. X-rays with energies above 25 keV have a major advantage, as they can penetrate through thick samples and walls of containers and permit investigation of samples under realistic flow conditions. As an example of the method, flow through a circular cross-section pipe with an internal diameter of 5 mm has been studied: this is typical of industrial applications. The angular distribution of intensities of peaks in the diffraction pattern as a function of the location of the pipe in the X-ray beam provides information about the alignment of particles under flow. Order parameters have been calculated to describe the alignment and direction of orientation. It is observed that the particles align in the direction of flow with their flat faces parallel to the flow. The experimental results are compared with the calculations of the local strain rate that help to explain the onset of alignment of the particles.
已采用高能量角度色散 X 射线衍射技术来研究胶体悬浮液中高岭石颗粒在沿管道流动时的排列情况。能量高于 25keV 的 X 射线具有显著优势，因为它们能够穿透厚样品和容器壁，并允许在实际流动条件下研究样品。作为该方法的一个示例，已经研究了通过内部直径为 5 毫米的圆形横截面管道的流动：这是工业应用的典型情况。作为 X 射线束中管道位置的函数，衍射图案中峰的强度的角度分布提供了有关流动下颗粒排列的信息。已计算了序参数以描述排列和方向。观察到颗粒沿流动方向排列，其平面平行于流动方向。将实验结果与局部应变速率的计算进行了比较，这有助于解释颗粒排列的开始。
