ISS: Uncovering transient dynamics and equilibrium states of particle aggregates in fluids

国际空间站：揭示流体中颗粒聚集体的瞬态动力学和平衡状态

• 批准号: 2224469
• 负责人: Raul Cal
• 金额: $ 91.48万
• 依托单位: Portland State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2224469&HistoricalAwards=false
• 关键词: ISS; Uncovering; transient; dynamics; equilibrium

Pollen deposition, paleoecology, algae growth linked to water quality, plastic pollution, and storm transported sea salt in bodies of water are at first examples of particles in fluid-gas interfaces. After a certain time, when and if particles sediment, the dynamics change and the involved processes can become those of a fluid-saturated granular media. Of particular interest for this proposal are externally vibrated particle-laden fluids that are used to segregate different particle sizes and materials, or to fluidize the granular material and thus improve its flow characteristics such as particulate transport and enhanced heat transfer. This project aims at exploring and quantifying transient dynamics of particles in an interface and bulk fluid in the absence of gravity and leading to improved aggregation models. The proposed research represents an important step forward towards the understanding of aggregation of particles in a bulk fluid and gas/fluid interface where times scales are relatively large and the effects are relatively small on Earth. This can aid the improvement of models of these transport phenomena in the overall balance of particle transport processes constantly occurring on Earth. This project is structured such to have a broader impact on the participating students and the broader public.A systematic experimental exploration of aggregation dynamics of particles in an unforced and forced interface and bulk fluid will be pursued. New knowledge and understanding about how these forces affect particle agglomeration rates in the absence of gravity will be created. To elucidate aggregation at liquid-gas interfaces and in a bulk fluid free from gravitational effects, a set of experiments to be performed on the International Space Station is proposed. Drop tower experiments at Portland State University will be performed to narrow parameters relevant to the study to inform relatively long experiments on the International Space Station under zero gravity in collaboration with ZIN Technologies. This project has three main objectives: 1.) Experimentally disentangle the effects on particles of capillary immersion from capillary floating and study the long-term particle dynamics of fluid saturated granular media through a zero-g environment unforced and subjected to an external harmonic forcing; 2.) Quantify collective effects promoted by agglomeration/clustering, particle-fluid and/or particle-particle interactions in a forced and unforced zero-g environment; and 3.) Develop agglomeration models truly representing effects in the absence of gravity on inertial particles. Broader impact activities are coordinated as: 1.) STEM training at the graduate and undergraduate level by a.) Leveraging existing programs at Portland State University as well as b.) Providing experiences to interface with partner company ZIN Technologies and NASA astronauts; and 2.) Oregon Museum of Science and Industry science communication training program will provide an important opportunity for the graduate student and post-doctoral researcher to effectively communicate their science with the broader public.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

花粉沉积、古生态学、与水质相关的藻类生长、塑料污染以及风暴在水体中输送的海盐是流体-气体界面中颗粒的第一个例子。经过一定的时间，当颗粒沉降时，动力学变化和所涉及的过程可以成为流体饱和颗粒介质的动力学变化和所涉及的过程。对于该提议特别感兴趣的是外部振动的载有颗粒的流体，其用于分离不同的颗粒尺寸和材料，或者用于分散颗粒材料，从而改善其流动特性，例如颗粒输送和增强的热传递。该项目旨在探索和量化在没有重力的情况下界面和本体流体中颗粒的瞬态动力学，并改进聚集模型。拟议的研究是朝着理解大量流体和气体/流体界面中颗粒聚集的重要一步，其中时间尺度相对较大，对地球的影响相对较小。这可以帮助改进这些传输现象的模型，在地球上不断发生的粒子传输过程的总体平衡中。本项目旨在对参与的学生和公众产生更广泛的影响。将对颗粒在非受迫和受迫界面和体相流体中的聚集动力学进行系统的实验探索。将创造关于这些力如何在没有重力的情况下影响颗粒团聚率的新知识和理解。为了阐明在液-气界面和在不受重力影响的散装流体中的聚集，提出了一套将在国际空间站上进行的实验。将在波特兰州立大学进行落塔实验，以缩小与研究有关的参数，为与ZIN技术公司合作在国际空间站上进行的零重力下的相对较长的实验提供信息。 该项目有三个主要目标：（1）。实验研究了毛细浸没和毛细漂浮对颗粒的影响，研究了零重力环境下流体饱和颗粒介质在无外力和外力作用下的长期颗粒动力学行为; 2.）量化在受迫和非受迫零g环境中由聚集/聚类、颗粒-流体和/或颗粒-颗粒相互作用促进的集体效应;以及3.）发展凝聚模型，真实地反映在没有重力的情况下对惯性粒子的影响。更广泛的影响活动协调如下：1.）在研究生和本科阶段的STEM培训。利用波特兰州立大学和B的现有课程。）提供与合作伙伴公司ZIN Technologies和NASA宇航员对接的经验; 2.）俄勒冈州科学与工业博物馆的科学传播培训计划将为研究生和博士后研究人员提供一个重要的机会，以有效地与更广泛的公众传播他们的科学。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。