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”是指一种流体烧蚀涂覆在固体基底上的第二种可混溶液体的层。这个过程在日常经验和许多工业过程中是常见的，特别是在清洁操作中。这种流动安排是伴随着一个经典的，“水跃”的现象，但分层的两种液体，具有不同的粘度，导致定性的新结果。在这项研究中的一个特别感兴趣的是在从固体，平面基板上的胶体颗粒的清洗时，液体涂层的基板（被冲洗掉）是非牛顿。初步数据表明，非牛顿聚合物和表面活性剂的解决方案，具有大的应变增稠拉伸粘度非常有效地“采摘”吸附的胶体颗粒从平面表面。然而，这只能通过包含延伸流动梯度的冲洗流动来实现。本研究将探讨冲洗流的流体力学作为两种流体（涂布液和喷射液）的粘度比的函数，并作为涂布液的流变特性的函数，使用高速摄影和粒子跟踪。还将直接测量真实的时间内的颗粒去除动态。另一个重要的考虑因素是其上施加冲洗流的固体基底的疏水性。PI的初步数据表明，基底的表面能对惯性去湿过程有深远的影响，本研究将探索这一现象。PI以前的NSF赞助的研究已经刺激了一些倡议，扩大了PI的学术活动的影响。除了参加大学的REU项目外，在过去的四个夏天里，PI还为当地高中生提供了机会。已向东帕洛阿尔托东区预备学校和桑尼维尔哈克学校的学生提供了职位。这项工作是由CBET的流体动力学和颗粒和多相计划共同资助的。