Collaborative Research: Droplet breakup in homogenous turbulence: model validation through experiments and direct numerical simulations

合作研究：均匀湍流中的液滴破碎：通过实验和直接数值模拟进行模型验证

• 批准号: 2201707
• 负责人: Michael Olsen
• 金额: $ 40.66万
• 依托单位: Iowa 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: 2022-02-15 至 2025-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2201707&HistoricalAwards=false
• 关键词: Collaborative; Research; Droplet; breakup; homogenous

The breakage of liquid droplets in a turbulent fluid flow is an important phenomenon in numerous engineering, scientific, and environmental applications. For example, many chemical and pharmaceutical processing techniques involve droplets breaking as components mix and react. Droplet breakage is also important in environmental applications such as the dynamics of oil spills and their cleanup, and in the leakage of underground storage tanks into water sources. Scientists and engineers have worked to develop computational techniques to predict complex fluid processes such as those listed above. A key component of these computational techniques are models that accurately describe droplet breakage and its dependence on flow parameters such as turbulence intensity and droplet properties such as viscosity, surface tension, diameter, and density. This project will conduct a series of experiments to measure droplet breakage under highly controlled conditions. Data from the experiments will be used to improve droplet breakage models.This project will investigate effects of turbulence intensity and fluid properties on droplet breakage by performing detailed experiments and using these data to improve and validate droplet breakage models. In the experiments, individual droplets will be injected into a flow chamber that has been designed to generate a uniform turbulent field. The turbulent field will be characterized using particle image velocimetry. High-speed movies will be captured of the droplet as it is deformed and then broken by the turbulence. The experiments will be repeated for different droplet diameters and fluids, and large ensembles of droplet breakage movies will be analyzed statistically to yield data on the droplet breakup process, including droplet size and shape. Moreover, because the timing of successive images in the movies will be known, droplet breakage event timings and frequencies can be determined by analyzing each image sequence. Graduate and undergraduate students will work on this project. Local high-school students will be recruited to participate as part of the research team through the Ames (Iowa) High School Enhanced Learning Program.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.

液滴在湍流流动中的破碎是许多工程、科学和环境应用中的重要现象。 例如，许多化学和药物加工技术涉及当组分混合和反应时液滴破裂。液滴破碎在环境应用中也很重要，例如石油泄漏的动力学及其清理，以及地下储罐泄漏到水源中。 科学家和工程师们一直致力于开发计算技术来预测复杂的流体过程，如上面列出的那些。这些计算技术的一个关键组成部分是精确描述液滴破碎及其对湍流强度等流动参数和粘度、表面张力、直径和密度等液滴特性的依赖性的模型。 该项目将进行一系列实验，以测量高度控制条件下的液滴破碎。 本项目将通过详细的实验，研究湍流强度和流体性质对液滴破碎的影响，并利用这些数据来改进和验证液滴破碎模型。在实验中，单个液滴将被注入到设计用于产生均匀湍流场的流动室中。湍流场的特点是使用粒子图像测速。 高速电影将被捕获的液滴，因为它是变形，然后打破了湍流。将针对不同的液滴直径和流体重复实验，并且将对液滴破碎电影的大集合进行统计分析，以产生关于液滴破碎过程的数据，包括液滴尺寸和形状。此外，因为电影中的连续图像的定时将是已知的，所以可以通过分析每个图像序列来确定液滴破裂事件定时和频率。研究生和本科生将在这个项目上工作。通过艾姆斯（爱荷华州）高中增强学习计划，当地高中学生将被招募参加研究团队。该奖项反映了NSF的法定使命，并被认为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来支持。

项目成果

Turbulent droplet breakage probability: Analysis of fitting parameters for two commonly used models

湍流液滴破裂概率：两种常用模型的拟合参数分析

• DOI: 10.1016/j.ces.2022.118311
• 发表时间: 2023
• 期刊: Chemical Engineering Science
• 影响因子: 4.7
• 作者: Ravichandar, Krishnamurthy;Olsen, Michael G.;Dennis Vigil, R.
• 通讯作者: Dennis Vigil, R.

Fitting parameter estimations for droplet breakage rate models

• DOI: 10.1063/5.0173987
• 发表时间: 2024-01
• 期刊: Physics of Fluids
• 影响因子: 4.6
• 作者: Krishnamurthy Ravichandar;R. D. Vigil;Michael G. Olsen