Liquid-Solid Flows with Inertia and Particle Settling

含有固体颗粒的液体流动在各种行业中都很重要，例如煤泥管道、水力压裂工艺和能源生产材料的加工。例如，从生物质中生产燃料需要研磨生物质，然后将其与水混合，形成沉淀的固体生物质颗粒的浆液，然后将其泵入反应堆进行进一步处理。了解这些液固浆体以及它们在流动中的行为将使它们在加工过程中使用更少的水和能量。类似的例子也出现在核废料的处理和储存以及各种地球物理流动中，包括山体滑坡和泥沙运输。该奖项将支持在液体和固体的惯性都很重要的条件下进行液固流动的独特实验。这一惯性体系在包括上述问题在内的一系列工业问题中都很重要，以前从未被研究过。这项研究使用定制的仪器，将提供一组实验数据，这些数据可以用来帮助预测颗粒沉降、颗粒床膨胀和流动这些浆液所需的力。研究的一个组成部分是对学生的教育。此外，还将创建一系列在线模块，以解决女性在科学、技术、数学和工程领域面临的挑战，以及如何使STEM的学术和研究环境更具包容性。该提案的目标是使用定制的流变仪研究非胶体颗粒悬浮，并在尚未探索的固体体积分数和颗粒雷诺数参数范围内产生丰富的实验数据集。该装置在同心圆柱体之间产生流动，使用中性浮力或沉降颗粒进行测量将覆盖从0.1到1,400的颗粒雷诺数和从稀释到稠密的固体分数。测量内容包括：1)在各种流动条件下，中性浮力悬浮液的剪应力和碰撞颗粒压力，包括湍流悬浮流；2)颗粒密度高于周围流体时的应力和床层膨胀；3)局部颗粒速度的两个分量，固体分数的垂直变化，以及颗粒碰撞。得到的数据集将作为惯性液-固流模拟和模型的宝贵基准，并将为理解颗粒涨落的作用和颗粒流中向湍流的转变提供基础。

Flows of liquids that contain solid particles are important in a wide variety of industries, with examples that include coal slurry pipelines, hydraulic fracturing processes, and the processing of materials for energy production. For example, the production of fuel from biomass involves grinding the biomass, then mixing it with water to create a slurry of settling, solid biomass particles that are then pumped into a reactor for further processing. Understanding these liquid-solid slurries and how they behave in flow will enable the use of less water and energy in their processing. Similar examples occur in the handling and storage of nuclear wastes, and in a wide range of geophysical flows including landslides and sediment transport. This award will support unique experiments on liquid-solid flows under conditions where the inertia of both the liquid and the solid are important. This inertial regime is important in a range of industrial problems including those above and has not been previously studied. This research, using a custom-built instrument, will provide a set of experimental data that can be used to help predict particle settling, particle bed expansion, and the forces required to flow these slurries. An integral part of the research is the education of students. In addition, a series of online modules will be created to address challenges facing women in the fields of science, technology, mathematics, and engineering and how to make STEM academic and research environments more inclusive.The goal of the proposal is to study non-colloidal particle suspensions using a custom-built rheometer, and to produce a rich experimental data set in an unexplored parameter regime of solid volume fraction and particle Reynolds number. The apparatus generates flow between concentric cylinders, and measurements using either neutrally-buoyant or settling particles will cover particle Reynolds numbers from 0.1 to 1,400 and solid fractions from dilute to dense. Measurements will include 1) the shear stress and the collisional particle pressure for neutrally-buoyant suspensions over a wide range of flow conditions, including turbulent suspension flows, 2) the stresses and bed expansion for conditions in which the particles are denser than the surrounding fluid, and 3) two-components of the local particle velocities, the vertical variation in solid fraction, and particle collisions. The resulting data set will serve as a valuable benchmark for simulations and models of inertial liquid-solid flows, and will provide a basis for understanding the role of particle fluctuations and the transition to turbulence in particulate flows.