Interplay between orientation and lift forces on non-spherical particles in complex fluids

复杂流体中非球形颗粒的方向力和升力之间的相互作用

• 批准号: 2341154
• 负责人: Vivek Narsimhan
• 金额: $ 45万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-04-15 至 2027-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2341154&HistoricalAwards=false
• 关键词: Interplay; between; orientation; lift; forces

Viscoelastic suspensions are polymeric fluids containing particles. These systems are everywhere in our daily lives, for example, found in foods, consumer products, coatings, adhesives, and pastes (e.g., 3D printing). These systems are also common in biological fluids (e.g., mucous, blood, bacterial suspensions). One interesting feature of viscoelastic suspensions is that particles in such fluids acquire lift forces during pressure-driven flows that drive them toward specific regions in the fluid. This phenomenon is important in polymer processing because it determines the final structure of the materials. It is also important in microfluidic technologies where flow is used to separate biological suspensions by particle size and shape. While the lift forces are well-studied for spherical particles, little is known about how particle shape affects the lift because the phenomenon is highly coupled to the particle orientation, which itself is a function of the flow. This award will perform experiments, simulations, and theories to characterize the motion of non-spherical particles in polymeric fluids and quantify the coupling between the lift and orientation for different flow rates, particle geometries, fluid properties, and channel confinement. This information is valuable for processing rod-like and disk-like particles in viscoelastic suspensions in the applications mentioned above, as it provides design guidelines for the migration time and final location for different particle shapes.This study specifically will perform microfluidic experiments where one flows a dilute suspension of spheroids (prolate and oblate) through a tube. Different fluids and channel sizes will be used, allowing one to systematically vary the fluid properties and channel confinement. The particle’s 3D position and orientation distribution at different channel locations will be visualized using holography, allowing one to obtain long-time particle positions and rate of migration. Direct numerical simulations and theories will complement the studies, developing relationships for lift forces in this geometry as well as other geometries that are important for fluid characterization. Both investigators will create demos about complex fluids for Purdue’s Women in Engineering Program, as well as create similar exhibits for elementary school students at Imagination Station, a local science center. These exhibits will be run by undergraduates working in the respective labs and an honors engineering society advised by the investigators. Lastly, undergraduates from underrepresented communities will be recruited for research through Purdue’s SURF program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

粘弹性悬浮液是含有颗粒的聚合物流体。这些系统在我们的日常生活中无处不在，例如在食品，消费产品，涂料，粘合剂和糊状物（例如3D打印）中发现。这些系统在生物笛子中也很常见（例如粘液，血液，细菌悬浮液）。粘弹性悬浮液的一个有趣特征是，这种笛子中的颗粒在压力驱动的流动过程中获取了升力力，从而将其驱动到流体中的特定区域。这种现象在聚合物加工中很重要，因为它决定了材料的最终结构。在微流体技​​术中也很重要，在微流体技​​术中，流量用于按粒径和形状分离生物学悬浮液。虽然升力力对于球形颗粒进行了充分研究，但对于颗粒形状如何影响升力，由于该现象高度耦合到粒子方向，该奖项本身就是该奖项将执行实验，模拟和理论来表征非球形粒子在聚合物流体中的非球形和量化范围的范围和量化量的不同范围的流动率和量化的范围，因此该奖项的函数几乎知之甚少，这本身就是一个功能。 一体化。该信息对于上述应用中的粘弹性悬浮液中的类似杆状和磁盘样颗粒很有价值，因为它为不同粒子形状的迁移时间和最终位置提供了设计指南。这项研究专门进行微流体实验，其中一个人将通过praleoids（prallate and Obsebate and Obledate）进行微流体实验。将使用不同的流体和通道尺寸，从而使一个人系统地改变流体特性和通道积分。粒子在不同通道位置的3D位置和方向分布将使用全息图可视化，从而使一个人获得长期粒子位置和迁移速率。直接的数值模拟和理论将补充研究，在本几何形状以及其他对流体表征重要的几何形状中发展的关系。两位研究人员都将为普渡大学的工程计划中的女性创建有关复杂流体的演示，并为当地科学中心Imagination Station的小学生创建类似的展览。这些展览将由在主要实验室工作的大学生和研究人员建议的荣誉工程协会进行。最后，将通过普渡大学的冲浪计划招募来自代表性不足的社区的大学生。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响审查标准来评估，被认为是珍贵的支持。