Plasma Breakdown and Instabilities in the Multiphase Plasma-Gas Bubble-Liquid System

这项研究项目将研究水中气泡与大气压等离子体的相互作用-大气压等离子体是由带电离子和电子、中性原子和分子以及各种活性物种组成的物质的第四种状态。由等离子体、气体和液体组成的具有急剧性质变化的气/液系统在从水清洁到农业应用以及用于医疗的等离子体激活液体等许多应用领域有着令人难以置信的前景。尽管在理解等离子体-液体相互作用方面取得了很大进展--包括开发了第一个被称为“永远分子”的大型含氟有机化合物降解装置--但迄今为止，对多相等离子体-气泡-液体系统中的等离子体击穿机制的详细研究还很少。多相系统本身和这种系统中的电击穿机制没有被很好地理解，阻碍了等离子体-气泡-液体系统的有效使用。在该项目中进行的此类系统的探索将造福社会，可能导致新的新兴应用，以解决地下水污染、医院废水细菌污染、农场提供化肥以及在水变得越来越珍贵的时候减少灌溉所需水量等问题。尽管已经对等离子体-液体相互作用进行了广泛的研究，但这个多学科的课题仍然对科学界构成了挑战。气泡的引入引起了人们的极大兴趣，因为它在这个影响等离子体行为的多相系统中打开了另一个自由度。此外，气泡在液体中普遍存在，通过等离子体-液体界面的能量传输，可以在整个液体中产生额外的气泡。因此，气泡的行为以及气泡对等离子体形成的影响引起了整个等离子体-液体科学界的极大兴趣。该项目通过多相建模和实验相结合的方式，解决了对气泡形成、气泡与电场的相互作用、等离子体相互作用以及气泡对电击穿的影响等基本定量理解的迫切需要。以前的研究中已经观察到了电击穿后的界面不稳定性，但还没有找到对这种行为的根本解释。多相等离子体-气泡-液体模拟将全面解决这一复杂系统。该项目将探索多相等离子体-气泡-液体系统中的电击穿，将气泡的性质与电击穿条件相关联，并探索电击穿后气/液界面的不稳定性。实验和模拟的结合将使人们能够从根本上了解多相等离子体-气泡-液体系统中的故障和不稳定性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research project will study the interaction of air bubbles in water with atmospheric pressure plasma – the fourth state of matter composed of charged ions and electrons, neutral atoms and molecules, and a variety of reactive species. Gas/liquid systems with steep property changes consisting of plasma, gas, and liquid have incredible promise for many applications ranging from water cleaning to agriculture applications and plasma-activated liquids for medical use. Although much progress has been made in understanding plasma-liquid interactions - including the development of the first upscaled devices for the degradation of fluorinated organic compounds known as "forever molecules" - to date there have been only a few detailed investigations on plasma breakdown mechanisms in the multiphase plasma-bubble-liquid system. The multiphase system itself and the electrical breakdown mechanisms in such systems are not well understood, hampering efficient use of plasma-bubble-liquid systems. Exploration of such systems conducted within this project will benefit society, potentially leading to new emerging applications to solve problems like groundwater contamination, bacterial contamination of hospital wastewater, providing fertilizer on-farm, and reducing the amount of water needed for irrigation in times when water is becoming increasingly precious.Although extensive research has been performed on plasma-liquid interactions, this multidisciplinary topic still challenges the scientific community. The introduction of gas bubbles is of great interest because it opens another degree of freedom in this multiphase system that influences the plasma behavior. Furthermore, bubbles are ubiquitous in liquids, and additional bubbles can be produced throughout the liquid by energy transport at the plasma-liquid interface. Thus, the behavior of bubbles and the impact of bubbles on the formation of plasma are of great interest for the whole plasma-liquid scientific community. This project addresses the critical need for developing a fundamental quantitative understanding of the bubble – from bubble formation, the interaction of the gas bubbles with the electric field, plasma interaction, to its impact on the electrical breakdown by combining multiphase modeling and experiments. Interface instabilities after electrical breakdown have been observed in previous research, but no fundamental explanation for this behavior has been found. The multiphase plasma-bubble-liquid simulations will comprehensively address this complex system. This project will explore the electrical breakdown in the multiphase plasma-bubble-liquid system, correlate the bubble properties to electrical breakdown conditions, and explore the gas/liquid interface instabilities after electrical breakdown. The combination of experiments and simulations will enable fundamental understanding of the breakdown and instabilities in the multiphase plasma-bubble-liquid system.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.