Water Spray in Atmospheric Pressure Electrical Discharge Plasma

[0932481]该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。液体（例如水）与等离子体（通常是电离气体）的相互作用出现在广泛的技术应用和自然现象中，包括关节镜手术的液相放电、肾结石治疗的碎石、伤口愈合和消毒、纳米颗粒合成、等离子体辅助燃烧、化学分析的微传感器、闪电放电、使用等离子体致动器的高压电力传输和气流控制中的腐蚀。气液等离子体中的等离子体化学反应这一相对未开发的领域也可能对气液化学反应重要的工业重要应用产生广泛影响（例如，空气污染研究和控制以及甲醇或氢和其他燃料等有用化学品的生产）。这项工作将重点研究气相放电，将微米大小的小水滴喷射到等离子体中，因为这种方法已被证明在启动各种化学反应（包括过氧化氢的形成）方面具有潜在的非常节能的潜力。等离子体相互作用的分析，特别是在这种系统中与小水滴引发的化学反应，对于发展我们对等离子体与冷凝液体的理解至关重要。这项工作将集中在两种一般情况下：1)反应产物，包括过氧化氢、氧和氢，来自纯水与Ar和O2载体气体；2)由甲烷和带有Ar载体的水滴形成甲醇。第一种情况对于在等离子体中引发的所有羟基自由基反应都至关重要，而第二种情况在生产液体燃料的能源领域具有重要意义，它提供了一个具有相当好表征的反应途径和机制的气液反应的例子。拟议的工作将使用一系列实验技术，包括气溶胶粒径测量、流动可视化、发射光谱和化学分析，以加深我们对像羟基自由基这样的反应性化学物质是如何由流入等离子体反应器的水滴形成的理解。将对耦合到等离子体化学反应的输运进行数学建模。利用分子动力学的基本分析也将进行，以研究电子与冷凝水表面的基本相互作用，并协助解释实验研究。该项目预计将导致有关气液环境中的等离子体如何导致反应物质形成以及它如何影响上述一些应用的基础知识的发展。在跨学科和国际化的环境下，对化学、机械和电气工程领域的本科生、博士生和博士后进行高等教育和培训，并对化学工程领域的一名年轻教师进行指导。

0932481LockeThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The interaction of liquid (e.g., water) with plasma (typically an ionized gas) occurs in a wide range of technological applications and natural phenomena including liquid-phase electrical discharge for arthroscopic surgery, lithotripsy for kidney stone treatment, wound healing and disinfection, synthesis of nanoparticles, plasma-assisted combustion, microsensors for chemical analysis, lightning discharges, corrosion in high-voltage electrical transmission and air flow control using plasma actuators. The relatively unexplored field of plasma-chemical reactions in gas-liquid plasma may also have a broad impact in industrially important applications where gas-liquid chemical reactions are important (e.g., air pollution study and control and the production of useful chemicals such as methanol or hydrogen and other fuels). This work will focus on studying a gas-phase electrical discharge with a spray of small micron-size water droplets into the plasma because this approach has been shown to be potentially very energy efficient for initiating a variety of chemical reactions, including the formation of hydrogen peroxide. Analysis of plasma interactions, particularly the chemical reactions initiated in such systems with small droplets of water, is vital to developing our understanding of plasma with condensed liquids in general. This work will focus on two general cases of 1) reaction products, including hydrogen peroxide, oxygen, and hydrogen, from pure water with Ar and O2 carrier gases and 2) formation of methanol from methane and water droplets with Ar carrier. The first case is of fundamental importance for all hydroxyl radical reactions initiated in the plasma and the second, while of significant importance in the energy field for production of liquid fuels, provides an example of gas-liquid reactions with reasonably well characterized reaction pathways and mechanisms. The proposed work will use a range of experimental techniques including aerosol particle size measurements, flow visualization, emissions spectroscopy, and chemical analysis to develop our understanding of how reactive chemical species like hydroxyl radicals are formed by water droplets flowing into a plasma reactor. Mathematical modeling of the transport coupled to the plasma chemical reactions will be conducted. Fundamental analysis using molecular dynamics will also be conducted to study the basic interactions of electrons with condensed water surfaces and to assist in interpretation of the experimental studies. This project is expected to lead to the development of fundamental knowledge on how plasma in gas-liquid environments leads to the formation of reactive species and how it affects some of the applications mentioned above. Advanced education and training of undergraduate students, PhD students, and a postdoctoral researcher in chemical, mechanical, and electrical engineering in an interdisciplinary and international environment will be conducted, and the mentoring of a young faculty member in chemical engineering will be accomplished.