Salipante Paul F, Dharmaraj Vishnu, Hudson Steven D
National Institute of Standards and Technology, Materials Science and Engineering Division.
J Rheol (N Y N Y). 2020;64(3). doi: https://doi.org/10.1122/1.5128230.
The viscosity of a shear-banding wormlike micelle solution at high shear rates is investigated using capillary rheology and particle streak velocimetry. Measurements of the flow profile and pressure gradient show an extended entrance region, which exceeds a length to diameter ratio of 100, to reach a fully developed flow. We characterized this entrance region for capillaries with different cross-sections and use the results to select a downstream portion of the capillary where viscosity measurements can be made on fully developed flow. Measurements from this portion of the channel show a shear-thinning power-law behavior for all channel geometries from shear rates of 1000 to 120000 . Varying the surfactant concentration shows two distinct power-law behaviors that depend on both shear rate and concentration and are an indication of change in micelle length.
使用毛细管流变学和粒子条纹测速技术研究了剪切带化蠕虫状胶束溶液在高剪切速率下的粘度。流动剖面和压力梯度的测量结果显示存在一个扩展的入口区域，其长度与直径之比超过100，以达到充分发展的流动状态。我们对具有不同横截面的毛细管的这个入口区域进行了表征，并利用结果选择毛细管的下游部分，在该部分可以对充分发展的流动进行粘度测量。通道这一部分的测量结果表明，在1000至120000的剪切速率范围内，所有通道几何形状均呈现剪切变稀幂律行为。改变表面活性剂浓度会显示出两种不同的幂律行为，这取决于剪切速率和浓度，表明胶束长度发生了变化。
