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

该研究项目将研究水中气泡与大气压等离子体的相互作用-由带电离子和电子，中性原子和分子以及各种反应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体/液体系统对于从水清洁到农业应用和用于医疗用途的等离子体活化液体的许多应用具有令人难以置信的前景。虽然在理解等离子体-液体相互作用方面取得了很大进展-包括开发用于降解被称为“永久分子”的氟化有机化合物的第一个升级设备-迄今为止，在多相等离子体-气泡-液体系统中对等离子体击穿机制的详细研究很少。 多相系统本身和在这样的系统中的电击穿机制还没有很好地理解，阻碍了等离子体-气泡-液体系统的有效使用。 在本项目中进行的对这种系统的探索将造福社会，可能导致新的新兴应用，以解决诸如地下水污染、医院废水的细菌污染、农场提供肥料以及在水变得越来越珍贵的时候减少灌溉所需的水量等问题。虽然已经对等离子体-液体相互作用进行了广泛的研究，这一多学科课题仍然是科学界面临的挑战。气泡的引入引起了极大的兴趣，因为它在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，气泡在液体中是普遍存在的，并且通过等离子体-液体界面处的能量传输可以在整个液体中产生额外的气泡。因此，气泡的行为和气泡对等离子体形成的影响是整个等离子体-液体科学界的极大兴趣。 该项目解决了开发气泡的基本定量理解的关键需求-从气泡形成，气泡与电场的相互作用，等离子体相互作用，到其对电击穿的影响，结合多相建模和实验。电击穿后的界面不稳定性在以前的研究中已经被观察到，但还没有找到对这种行为的基本解释，多相等离子体-气泡-液体模拟将全面解决这个复杂的系统。本计画将探讨多相电浆-气泡-液体系统中的电击穿现象，将气泡特性与电击穿条件相关联，并探讨电击穿后的气/液界面不稳定性。实验和模拟的结合将使多相等离子体-气泡-液体系统的故障和不稳定性的基本理解。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。

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.