电场作用下同轴流动聚焦的复合射流不稳定性特性研究

项目名称： 电场作用下同轴流动聚焦的复合射流不稳定性特性研究

项目编号： No.11472270

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 司廷

作者单位： 中国科学技术大学

项目金额： 90万元

中文摘要： 本申请提出将同轴结构的流动聚焦、电雾化和电纺丝三种技术相结合的方法，在同轴流动聚焦的复合锥形和射流区域施加电场作用，采用先进的显微系统结合高速摄影机和激光切片流场显示技术，获得高速运动复合气-液射流的清晰图像和定量数据，并利用理论分析方法研究在多相流和多场耦合条件下带电复合射流的不稳定性特性，力求获得电场作用下同轴流动聚焦的物理规律和力学机理。通过本项目研究，建立复杂条件下同轴结构毛细流动的实验研究平台，获取不同控制参数下牛顿流体和非牛顿流体带电复合射流的直径、速度、扰动发展和失稳模态，得到流动模式及其参数域，并给出优势模态之间相互转变的主要影响因素和规律，为实际应用提供理论指导。与单一的同轴技术相比，该方法在制备微纳米尺度的胶囊和复合纤维方面更有优势，有望使雾化更稳定，可应用的参数范围更广，制备的产物直径更小，因此具有重要而广泛的应用前景。

中文关键词： 同轴流动聚焦；流动稳定性；复合射流；多相流；多场耦合

英文摘要： The project proposes the method for combination of three coaxial techniques involving co-flow focusing, coaxial electrospray and co-electrospinning, where an electric field is applied in the region of compound cone and jet in co-flow focusing. By means of the advanced microscopic system combined with high-speed video camera and laser sheet section-cutting visualization techniques, we aim to obtain the sharp images and quantitative data of gas-liquid compound jets moving with high velocity. The instability characteristics of compound jets under multiphase flow and multi-field coupling conditions are also investigated theoretically. As a whole, the physical rules and dynamic mechanisms of co-flow focusing under an electric field are expected to be obtained. According to the research in this project, the experimental platform for studying the coaxial capillary flows under complex conditions will be established; the data of electrified compound jet for both Newtonian and non-Newtonian fluids including the diameter, the velocity, the growth rate of disturbances and the unstable modes will be explored in a range of different control parameters; the flow modes and corresponding parametric regimes will be given; the effects and physical rules of main influencing factors on the transitions between different dominant unstable modes will be obtained. The results will provide theoretical guidance to practical applications. Compared to each of these coaxial techniques, the method reported here is more advantageous for producing microcapsules and compound fibers with micro-/nanometer scales, and it is hopeful of stabilizing the atomization, widening the range of applied parameters and reducing the diameter of productions. As a result, this method possesses significant and extensive application prospects.

英文关键词： Co-flow focusing;flow instability;compound jet;multiphase flow;multi-field coupling