Nonlinear-Flow-Induced Structure in Fiber Suspensions

纤维悬浮液中的非线性流动诱导结构

• 批准号: 9910908
• 负责人: Donald Koch
• 金额: $ 25万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9910908&HistoricalAwards=false
• 关键词: Nonlinear; Flow; Induced; Structure; Fiber

AbstractCTS-9910908D. L. Koch, Cornell UniversityThe rheological behavior of such complex fluids as fiber suspensions, crystal polymers, etc. are important in the paper, food, and pharmaceutical industries. Linear solutions exist for a number of these flows, but for many applications, nonlinear terms become important and must be included. It is proposed to study thee nonlinearities in the context of four situations highlighting viscoelasticity, fluid inertia, electrical double layer interactions, and fiber-fiber adhesion:i) Oscillatory linear flows do not show any change of orientation from one cycle to the next: there is, however, a cumulative drift of orientation when non-linear terms appear. Three such cases will be studied for a wide range of amplitude and frequency.ii) The case of fibers suspended in fluids emphasizes the inertia forces when considering their length (high Reynolds numbers), but viscous effects may dominate when the fiber diameter is the relevant dimension (Reynolds numbers near unity). A slender body theory will be developed and applied to the case of a single rotating fiber in a Couette flow.iii) Electrically charged rods are expected to interact with ions of opposite charge, with their resulting effect on the rod orientation. Experiments are planned to test the PI's earlier theoretical work on electoviscous effects.iv) Dense suspensions bring together viscous effects (fluid-body surface interaction) and Columbic friction laws (body-body contact). Such interactions will be studied with special attention to adhesive fiber-fiber contact.

摘要CTS-9910908 D。L.纤维悬浮液、晶体聚合物等复杂流体的流变行为在造纸、食品和制药工业中很重要。 这些流中有许多存在线性解，但对于许多应用，非线性项变得重要，必须包括在内。 建议在突出粘弹性、流体惯性、双电层相互作用和纤维-纤维粘附的四种情况下研究这些非线性：i）振荡线性流动不显示从一个循环到下一个循环的取向的任何变化：然而，当非线性项出现时，存在取向的累积漂移。 三个这样的情况下，将研究一个宽范围的振幅和频率。ii）的情况下，纤维悬浮在流体中强调的惯性力时，考虑其长度（高雷诺数），但粘性效应可能占主导地位时，纤维直径是相关的尺寸（雷诺数接近统一）。 一个细长体理论将开发和应用到一个单一的旋转纤维的情况下，在库埃特流。三）带电杆预计将与离子的相反电荷，其结果对杆的方向。 实验计划，以测试PI的早期理论工作的electovisky效果。iv）密集的悬浮液带来了粘性效应（流体-物体表面相互作用）和哥伦布摩擦定律（身体-身体接触）。 这种相互作用将特别注意研究粘合剂纤维-纤维接触。