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.

当气泡上升到水面并破裂时，细菌和病毒等颗粒物可能会从受污染的水源中雾化，形成喷射水滴。这些喷射液滴中的细菌浓度高得惊人，比来源浓度高出 1000 倍。这种富集可能是由于气泡在上升时清除颗粒而发生的。 如果是这样，富集程度应取决于气泡破裂前颗粒与气泡的距离。 然而，仅基于这些想法的预测与现有数据集不一致。该项目的目标是揭示决定封装在这些液滴中的各种类型和尺寸颗粒的富集因子的流体动力学。研究结果对于与健康和环境相关的各种问题可能很重要。具体来说，该研究将从机械角度理解特定病原体在特定大小的喷射液滴中的富集程度。这些信息对于预测接触受污染水源的人的感染风险以及确定适当的缓解策略至关重要。此外，病毒和其他海洋衍生颗粒在喷射液滴中的传输会对云的形成产生影响，这与全球气候模型相关。此外，微塑料等其他海洋颗粒物的传输是一个重要的环境问题，了解颗粒物富集对于估计空气-水界面的传输速率至关重要。该项目还将为幼儿教育教师和工程研究生提供使用水滴和气泡作为途径的机会，以提高教育工作者和年轻学习者对 STEM 过程的可见性和可及性。数十年的研究探索了上升的气泡如何清除受污染水源中的悬浮颗粒，并将颗粒与气泡一起带到水面。同样，重要的研究也探索了气泡在破裂时如何产生喷射液滴，部分原因是这些喷射液滴中的颗粒对健康和环境产生的影响。然而，人们对气泡破裂过程中颗粒如何输送到喷射液滴中的了解有限。这种理解对于预测喷射液滴中观察到的浓度增加至关重要，也是该项目的目标。通过直接实验、数值模拟和适当维度化的机械模型的结合，将研究封装颗粒的微观流体动力学。将特别注意那些可能通过清除而带到表面但由于其尺寸、物理性质和位置而未被封装的颗粒。通过对封装过程进行建模，可以预测无法进行实验或具有潜在危险的颗粒物的气溶胶液滴浓缩程度。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。

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