Particle Removal from Surfaces using Rinsing Flows with Extensional Viscosity Liquids

使用具有拉伸粘度液体的冲洗流去除表面颗粒

• 批准号: 0930100
• 负责人: Gerald Fuller
• 金额: $ 30万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0930100&HistoricalAwards=false
• 关键词: Particle; Removal; Surfaces; using; Rinsing

Fuller0930100"Rinsing flows" are where one fluid ablates a layer of a second, miscible liquid that coats a solid substrate. This process is common to everyday experience and to many industrial processes, particularly in cleaning operations. This flow arrangement is accompanied by a classic, "hydraulic jump" phenomenon but the stratification of two liquids, with differing viscosities, leads to qualitatively new results. A particular interest in this study is during the cleaning of colloidal particles from solid, planar substrates when the liquid coating the substrate (the one being rinsed off) is non-Newtonian. Preliminary data are offered that demonstrate that non-Newtonian polymer and surfactant solutions with large strain thickening extensional viscosities very effectively "pluck" adsorbed colloidal particles from planar surfaces. However, this can only be accomplished by rinsing flows that contain extensional flow gradients. This research will explore the fluid mechanics of rinsing flows as a function of the viscosity ratio of the two fluids (the coating liquid and the jet liquid) and as a function of the rheological character of the coating liquids using high-speed photography and particle tracking. The dynamics of particle removal in real time will also be directly measured. Another important consideration is the hydrophobicity of the solid substrates onto which the rinsing flows are applied. The PI's preliminary data demonstrate that the surface energy of the substrates has a profound effect on the process of inertial dewetting and this research will explore this phenomenon. The PI's previous NSF sponsored research has stimulated a number of initiatives that broadened the impact of the PI's scholarly activities. In addition to participating in a REU program at the university, for the past four summers the PI has extended opportunities to local high school students. Positions have been made available to students from Eastside Preparatory School in East Palo Alto and Harker School in Sunnyvale. This work is jointly funded by the Fluid Dynamics and Particulate and Multiphase Programs of CBET.

fuller0930100“冲洗流”是一种流体在其中消灭一层可混杂的液体，可覆盖固体基材。这一过程对于日常经验和许多工业流程来说是普遍的，尤其是在清洁操作中。这种流程布置伴随着经典的“液压跳跃”现象，但是两个液体的分层具有不同的粘度，导致了定性的新结果。这项研究的特别兴趣是，当液体涂层底物（被冲洗液）是从固体，平面底物中清洁胶体颗粒期间，是非牛顿的。提供了初步数据，这些数据表明，非牛顿聚合物和表面活性剂溶液具有较大的应变增厚的伸缩粘度非常有效地“拔出”平面表面的吸附胶体颗粒。但是，这只能通过冲洗包含延伸流量梯度的流动来实现。这项研究将探索两种流体（涂层液体和喷气液）的粘度比的冲洗流动的流体力学，并使用高速摄影和粒子跟踪来探索涂层液体的流变特征的函数。实时去除粒子的动力学也将直接测量。另一个重要的考虑因素是应用冲洗流的固体底物的疏水性。 PI的初步数据表明，底物的表面能对惯性易碎的过程产生深远影响，这项研究将探索这一现象。 PI之前的NSF赞助研究刺激了许多计划，扩大了PI学术活动的影响。除了参加大学的REU计划外，在过去的四个夏天中，PI还向当地的高中生提供了机会。已经为来自东帕洛阿尔托（East Palo Alto）和桑尼维尔（Sunnyvale）的哈克学校（Harker School）的Eastside准备学校的学生提供了职位。这项工作由CBET的流体动力学以及颗粒和多相计划共同资助。