A bio-inspired strategy to dramatically reduce drag of particle-laden liquids over planar surfaces: characterization, theory and experiment

这一建议描述了一种统一的研究，它将揭示在存在滑移型边界条件的壁面上流动的悬浮物中粒子运动的相互作用。这项研究具有变革性，因为它将是第一个全面解决含有颗粒的液体在软多孔材料上的慢运动及其相关减阻问题的研究。该项目将大大提高对浆液在高度可压缩的多孔介质中流动行为的理解，在这种介质中，纤维可以充当润滑层，有可能极大地增加升力和减少阻力。所开发的实验方法和分析技术也可以应用于悬浮液和非牛顿流体在一系列结构/图案表面(如疏水表面)上的运动。所收集的见解可以显著推动基于微流控技术的设备在广泛的工业应用中的应用，包括生物医学领域、化学合成、(细胞)生物、食品和制药，以显著减少摩擦和磨损，从而提高这些设备的效率和运行寿命。这门统一课程的教材将通过向工科学生介绍悬浮流作为非牛顿流体力学的例子以及它们与多孔介质的相互作用来创建。本科生将通过McNair暑期研究计划、Clarkson的可持续发展REU计划、Clarkson的荣誉计划或研究选修课，作为研究人员参与这个项目。这项拟议研究的目的是为理解软质多孔材料上颗粒液体的流动提供基础，并利用这一理解来探索一种新的生物灵感概念，以大大提高润滑压力，同时显著降低在平面表面上流动的颗粒液体中的摩擦和阻力。这一概念的灵感来自于红细胞在毛细血管中几乎无摩擦地移动，涉及到在平面表面覆盖一系列具有特定渗透性和孔隙度的柔软多孔材料。该项目的目标是1)通过耦合Brinkman方程和扩散通量模型，并建立耦合流动的标度定律，开发一个分析模型，通过精确描述具有特定力学性质的随机排列的软质多孔介质上的泥浆慢运动，以及2)通过专门设计的实验装置，使用压降作为测量减阻的手段，并使用磁共振成像(MRI)和粒子图像测速仪(PIV)来测量流体速度，从而对该模型进行实验验证。

This proposal describes a unified study that will reveal the interactions of the motion of particles in a suspension flowing over a wall where slip-type boundary conditions exist. This research is transformative because it will be the first to comprehensively address the slow motion of particle-laden liquids over soft porous material and its related drag reduction. This project will substantially advance understanding of the behavior of slurry flows over highly compressible porous media in which the fiber can act as a lubricating layer, with the potential to vastly increase lift and reduce drag. The experimental methods and analysis techniques developed could also be applied to the motion of suspensions and non-Newtonian fluids over a broad array of structured/patterned surfaces such as hydrophobic surfaces. The insights gathered could significantly advance microfluidic-based devices in a wide range of industrial applications including, biomedical fields, chemical synthesis, (cell) biology, food, and pharmaceutics to drastically reduce friction and wear, leading to improved efficiencies and operating lifetimes for these devices. Teaching materials for this unified subject will be created by introducing suspension flows as an example of non-Newtonian fluid mechanics and their interaction with porous media to the engineering students. Undergraduates will participate as researchers in this project through the McNair summer research program, Clarkson's REU program in Sustainability, Clarkson's Honors program, or through a research elective. The goal of the proposed research is to provide the basis for understanding the flow of particle-laden liquids over soft porous materials, and use that understanding to explore a new bio-inspired concept for greatly enhancing the lubricating pressure while dramatically reducing friction and drag in a particle-laden slurry flowing over planar surfaces. This concept, inspired by the almost frictionless movement of red blood cells through capillaries, involves covering the planar surfaces with an array of soft porous material with a specific permeability and porosity. The objectives of the proposed project are to 1) develop an analytical model that accurately describes the slow motion of slurries over random arrays of soft porous media with specific mechanical properties by coupling the Brinkman equation with the diffusive flux model, and establishing scaling laws for coupled flows, and 2) experimentally validate that model by a specially designed experimental set-up using pressure drop as a means to measure drag reduction and magnetic resonance imaging (MRI) and particle-image velocimetry (PIV) to measurement fluid velocities.