Markmann V, Dartsch M, Valerio J, Frenzel L, Lokteva I, Walther M, Westermeier F, Grübel G, Lehmkühler F
Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany.
Struct Dyn. 2020 Oct 16;7(5):054901. doi: 10.1063/4.0000038. eCollection 2020 Sep.
We applied shear to a silica nanoparticle dispersion in a microfluidic jet device and observed direction-dependent structure along and across the flow direction. The asymmetries of the diffraction patterns were evaluated by x-ray cross correlation analysis. For different Rayleigh nozzle sizes and shapes, we measured the decay of the shear-induced ordering after the cessation of the shear. At large tube sizes and small shear rates, the characteristic times of the decay become longer, but Péclet-weighted times do not scale linearly with Péclet numbers. By modeling particle distributions with the corresponding diffraction patterns and comparing measured shape asymmetry to simulations, we determined the variation of volume fraction over the azimuthal angle for the maximum ordered state in the jet.
我们在微流体喷射装置中对二氧化硅纳米颗粒分散体施加剪切力，并观察到沿流动方向和垂直于流动方向的方向依赖性结构。通过X射线互相关分析评估衍射图案的不对称性。对于不同的瑞利喷嘴尺寸和形状，我们测量了剪切停止后剪切诱导有序性的衰减。在大管径和小剪切速率下，衰减的特征时间变长，但佩克莱加权时间与佩克莱数不成线性比例关系。通过用相应的衍射图案对颗粒分布进行建模，并将测量的形状不对称性与模拟结果进行比较，我们确定了射流中最大有序状态下体积分数随方位角的变化。
