A comprehensive mathematical model for nanofibre formation in centrifugal spinning methods
A comprehensive mathematical model for nanofibre formation in centrifugal spinning methods
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DOI：
10.1017/jfm.2020.196
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发表时间：
2020-06-10
影响因子：
3.7
通讯作者：
Taghavi, S. M.
中科院分区：
文献类型：
--
作者：
Noroozi, S.;Arne, W.;Taghavi, S. M.
基于我们对离心纺丝过程中纳米纤维形成的实验观察，我们首次发展了一个弦模型来研究牛顿粘性曲线射流在非正交曲线坐标系中的行为，该坐标系同时包括空气阻力效应和溶剂挥发。在离心纺丝中，聚合物溶液从围绕对称轴高速旋转的喷丝板的喷嘴中涌出，并随着喷嘴出口的离开而变薄，直到最终落在收集器上。除了牛顿流体假设外，我们的模型还包括弯曲射流的关键参数，例如粘性、惯性、旋转、表面张力、重力、射流内的质量扩散、质量扩散和空气动力学效应，通过Rossby()、Reynolds()、Weber()、Froude()、Peclet()、Air Reynolds()和Air Peclet()以及集热器的径向位置()。我们的结果，包括与实验的比较，表明必须考虑气动效应才能正确地预测喷流的轨迹和半径。减小不仅会使喷嘴变薄得更快，还会迫使喷嘴围绕旋转轴缠绕得更紧。增加，并导致更长的喷气式飞机。减小会导致喷嘴更紧密地缠绕在喷丝板周围，但对溶剂蒸发的影响微乎其微。和的变化不会对喷气轨迹产生显著影响。最后，我们提出了估算喷流半径和喷流破碎长度的简单关系式。
Motivated by our experimental observations of nanofibre formation via the centrifugal spinning process, we develop a string model to study the behaviours of a Newtonian, viscous curved jet, in a non-orthogonal curvilinear coordinate system including both air-drag effects and solvent evaporation for the first time. In centrifugal spinning a polymeric solution emerges from the nozzle of a spinneret rotating at high speeds around its axis of symmetry and thins as it moves away from the nozzle exit until it finally lands on the collector. Except for the Newtonian fluid assumption, our model includes the key parameters of the curved jet flow, e.g. viscous, inertial, rotational, surface tension, gravitational, mass diffusion within the jet, mass diffusion into air and aerodynamic effects, via Rossby (), Reynolds (), Weber (), Froude (), Peclet (), air Reynolds () and air Peclet () numbers, and the collector radial position (). Our results, including comparison to experiments, reveal that the aerodynamic effects must be considered to enable a correct prediction of the jet trajectory and radius. Decreasing not only renders the jet thinning much faster, but also forces the jet to wrap tighter around the rotation axis. Increasing , and leads to a longer jet. Decreasing causes the jet to wrap tighter around the spinneret but it shows trivial effects on the solvent evaporation. Changes in and do not significantly affect the jet trajectory. Finally, we propose simple relations to estimate the jet radius and the jet breakup length.