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

这一建议描述了一个统一的研究，将揭示在滑移型边界条件存在的壁上流动的悬浮液中粒子运动的相互作用。这项研究具有变革性，因为它将首次全面解决含颗粒液体在软多孔材料上的缓慢运动及其相关的减阻问题。该项目将极大地促进对泥浆在高可压缩性多孔介质上流动行为的理解，其中纤维可以作为润滑层，具有极大地增加升力和减少阻力的潜力。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广泛的结构/图案表面（如疏水表面）上的运动。所收集的见解可以显着推进基于微流体的设备在广泛的工业应用中，包括生物医学领域，化学合成，（细胞）生物学，食品和制药，以大幅减少摩擦和磨损，从而提高这些设备的效率和使用寿命。这门统一学科的教学材料将通过向工科学生介绍悬浮流作为非牛顿流体力学的一个例子以及它们与多孔介质的相互作用来创建。本科生将通过麦克奈尔暑期研究项目、克拉克森可持续发展REU项目、克拉克森荣誉项目或研究选修课，作为研究人员参与该项目的研究。本研究的目标是为理解含颗粒液体在软多孔材料上的流动提供基础，并利用这一理解探索一种新的生物启发概念，该概念可以大大提高润滑压力，同时显著减少在平面上流动的含颗粒泥浆中的摩擦和阻力。这个概念的灵感来自红细胞在毛细血管中几乎无摩擦的运动，包括用一系列具有特定渗透性和孔隙度的软多孔材料覆盖平面表面。该项目的目标是：1)通过将Brinkman方程与扩散通量模型耦合，建立一个准确描述浆料在具有特定力学性能的随机软多孔介质阵列上缓慢运动的分析模型，并建立耦合流动的标度规律；2)通过专门设计的实验装置对该模型进行实验验证，使用压降作为测量阻力减少的手段，并使用磁共振成像（MRI）和颗粒图像测速（PIV）来测量流体速度。

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.