Measuring and modeling particle enrichment in jet drops from bursting bubbles

测量和模拟气泡破裂喷射液滴中的颗粒富集度

• 批准号: 2114489
• 负责人: James Bird
• 金额: $ 33.85万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2114489&HistoricalAwards=false
• 关键词: Measuring; modeling; particle; enrichment; jet

Particulates, such as bacteria and viruses, can be aerosolized from contaminated water sources when air bubbles rise to the surface of the water and pop, forming jet drops. The concentration of bacteria in these jet drops can be surprisingly high, up to 1000 times more concentrated than in the source. This enrichment may occur because the bubble scavenges particles as it rises. If so, the degree of enrichment should depend on how close particulates are to the bubble immediately before it pops. However, predictions based solely on these ideas are inconsistent with existing data sets. The goal of this project is to uncover the fluid dynamics that determines the enrichment factor for various types and sizes of particles that are encapsulated into these droplets. The results could be important to a variety of problems related to health and the environment. Specifically, the research will lead to a mechanistic understanding of the extent that a particular pathogen is enriched in a particular-sized jet drop. This information is critical to predicting the risk of infection to people exposed to contaminated water sources and to determining appropriate mitigating strategies. Furthermore, the transport of viruses and other marine-derived particles in jet drops has an impact on cloud formation, which is relevant to global climate models. Additionally, the transport of other marine particulates such as microplastics is an important environmental concern, and an understanding of particulate enrichment is critical to estimate transfer rates across the air-water interface. This project will also provide opportunities for early childhood education teachers and engineering graduate students to use drops and bubbles as a pathway to increase the visibility and accessibility of STEM processes to educators and young learners.Decades of research has explored how rising bubbles can scavenge suspended particulates in a contaminated water source and bring the particulates along with the bubble to the water surface. Similarly, significant research has explored how bubbles can create jet drops as they rupture, motivated in part by the impact that particles within these jet drops can have on health and environment. However, there is limited understanding of how particulates are transported into jet drops during the bubble rupture process. This understanding is critical to predict the enhanced concentrations observed in jet drops and is the objective of this project. Through a combination of direct experiments, numerical simulations, and appropriately dimensionalized mechanistic models, the microscale fluid dynamics by which particles are encapsulated will be investigated. Particular attention will be given to particles that may be brought to the surface by scavenging, but not encapsulated due to their size, physical properties, and location. By modeling the encapsulation process, the degree to which aerosol droplets are concentrated can be predicted for particulates for which experiments are unfeasible or potentially hazardous.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.

当气泡上升到水和流行的表面并形成喷气液时，可以从受污染的水源中燃烧颗粒物，从污染的水源中燃烧。这些喷射液中细菌的浓度可能令人惊讶地高，浓度高达1000倍。这种富集可能是因为气泡清除颗粒时会升高。 如果是这样，那么富集的程度应取决于颗粒在弹出之前与气泡紧接的近距离。 但是，仅基于这些想法的预测与现有数据集不一致。该项目的目的是揭示确定封装在这些液滴中的各种类型和大小的颗粒的富集因子的流体动力学。结果对于与健康和环境有关的各种问题可能很重要。具体而言，这项研究将导致对特定病原体富含特定大小的喷射液的程度的机械理解。这些信息对于预测暴露于受污染的水源的人的感染风险和确定适当的缓解策略至关重要。此外，喷气液中病毒和其他海洋来源的颗粒的运输对云形成有影响，这与全球气候模型有关。另外，其他海洋颗粒（例如微塑料）的运输是一个重要的环境问题，对颗粒富集的理解对于估计整个空气水界面的转移速率至关重要。该项目还将为早期的儿童教育教师和工程研究生提供机会使用滴水和气泡作为增加对教育工作者和年轻学习者的STEM过程的可见性和可访问性的途径。研究的十年来探讨了升起的气泡如何清除污染的水源中的颗粒物，并将颗粒物与气泡一起带到水面上。同样，重要的研究探索了气泡在破裂时如何产生喷射液，部分原因是这些喷射液中的颗粒对健康和环境会产生的影响。但是，在气泡破裂过程中，对颗粒如何将颗粒输送到喷射液滴的了解有限。这种理解对于预测喷射液滴中观察到的增强浓度至关重要，并且是该项目的目的。通过直接实验，数值模拟和适当尺寸的机械模型的结合，将研究封装颗粒的显微镜流体动力学。特别关注可能通过清除可能带到表面的颗粒，但由于其大小，物理特性和位置而不会封装。通过对封装过程进行建模，可以预测，对于实验是不可行或潜在危险的颗粒物，可以预测气溶胶液滴的浓缩程度。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来支持的。

项目成果

Enrichment of Scavenged Particles in Jet Drops Determined by Bubble Size and Particle Position

• DOI: 10.1103/physrevlett.130.054001
• 发表时间: 2023-02-03
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Dubitsky, Lena;Mcrae, Oliver;Bird, James C.
• 通讯作者: Bird, James C.

Effects of Salinity Beyond Coalescence on Submicron Aerosol Distributions

• DOI: 10.1029/2022jd038222
• 发表时间: 2023-05
• 期刊: Journal of Geophysical Research: Atmospheres
• 作者: L. Dubitsky;M. D. Stokes;G. Deane;J. Bird