Liquid-Solid Flows with Inertia and Particle Settling

含有固体颗粒的液体流在各种行业中都很重要，例如煤浆管道，水力压裂工艺和能源生产材料的加工。 例如，从生物质生产燃料涉及研磨生物质，然后将其与水混合以产生沉降的固体生物质颗粒的浆料，然后将其泵入反应器中进行进一步处理。 了解这些液-固浆料以及它们在流动中的行为将使其在加工过程中使用更少的水和能源。 类似的例子也发生在核废料的处理和储存，以及包括滑坡和沉积物搬运在内的广泛的地球物理流动中。 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。 这种惯性状态在包括上述问题在内的一系列工业问题中是重要的，以前没有研究过。 这项研究，使用定制的仪器，将提供一组实验数据，可用于帮助预测颗粒沉降，颗粒床膨胀，以及流动这些浆料所需的力。 研究的一个组成部分是学生的教育。 此外，还将创建一系列在线模块，以应对女性在科学、技术、数学和工程领域面临的挑战，以及如何使STEM学术和研究环境更具包容性。该提案的目标是使用定制流变仪研究非胶体颗粒悬浮液，并在固体体积分数和颗粒雷诺数的未知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，并且使用中性浮力或沉降颗粒的测量将覆盖颗粒雷诺数从0.1到1，400和固体分数从稀到密。 测量将包括1）中性浮力悬浮液在宽范围的流动条件下的剪切应力和碰撞颗粒压力，包括湍流悬浮液流，2）颗粒比周围流体密度大的条件下的应力和床膨胀，以及3）局部颗粒速度的两个分量，固体分数的垂直变化和颗粒碰撞。由此产生的数据集将作为一个有价值的基准模拟和模型的惯性液-固流，并将提供一个基础，了解颗粒波动的作用和过渡到湍流的颗粒流。

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.