CAREER: Influence of electric fields on liquid-to-solid phase change associated with clathrate hydrate formation

职业生涯：研究电场诱导水合物形成的基本机制克拉酸盐水合物是一种水基晶体固体，由困在水分子晶格中的客体分子(甲烷、二氧化碳、四氢呋喃、环戊烷等)组成。水合物可以在天然气运输、海水淡化和碳封存等许多与能源和水相关的领域中作为新的应用基础。与水合物形成相关的一个重大挑战是水合物开始形成(成核)之前需要很长的等待时间，可能从几个小时到几天不等。最近的研究表明，外加电压可以显著加速水合物的形成，并将等待时间减少数百倍或更多。这种电成核概念可以快速和受控地合成水合物，以满足上述应用，所有这些应用都需要快速形成水合物。本项目是电场诱导水合物形成机理的基础性研究。分析了电荷、电流、换热和表面化学对三种水合物形成的影响。总体而言，这项工作将在水合物和液-固相变领域做出开创性的贡献。该项目的结果有可能完全消除水合物形成的延迟，并使“按需”水合物形成成为可能。这项研究的结果将被纳入教育活动，其中包括为本科生和代表性不足的少数群体开发一门研究生水平的相变传热学课程和研究机会。本课题研究了三种水合物的电成核。在第一组研究中，将分析两种互不相容的液体中水合物的形成。环戊烷水合物的形成将通过实验和分析模型进行研究，以量化电场和界面电荷对水合物成核的作用。在第二组研究中，将分析混合液体中水合物的形成。将对四氢呋喃水合物的形成进行分析，以了解电流和生成的气泡对成核的影响。第三组研究将分析甲烷水合物的电成核作用，即水合物在高压下在液-气界面成核。该项目包括成核-测量实验、分析多物理模型和关联开发。微流控电池将被制造出来，以获得具有统计意义的电成核估计。该项目的具体成果包括对电成核速率的测量，以及对各种水合物形成的物理基础的了解。这个项目将突出电场在从根本上将成核的性质从随机改变为确定性的作用。总体而言，这项研究将使我们能够深入了解电现象对与水合物形成相关的微/中尺度热流现象的影响。

CAREER: Investigation of the fundamental mechanisms underlying electric field-induced formation of hydratesClathrate hydrates are water-based crystalline solids consisting of a guest molecule (methane, carbon dioxide, tetrahydrofuran, cyclopentane and others) trapped in a lattice of water molecules. Hydrates can be the basis of novel applications in many energy-water related areas such as natural gas transportation, desalination and carbon sequestration. A significant challenge associated with hydrate formation is the long wait time before hydrates start forming (nucleate), which can range from hours to days. Recent studies indicate that applied electrical voltages can significantly accelerate hydrate formation, and reduce the wait time by a factor of hundred or more. This electro-nucleation concept can enable rapid and controlled synthesis of hydrates for the above applications, all of which require rapid hydrate formation. This project is a fundamental study of the mechanisms underlying electric-field induced formation of hydrates. The influence of electric charge, current flow, heat transfer and surface chemistry on hydrate formation will be analyzed for three kinds of hydrates. Overall, this work will lead to seminal contributions in the fields of hydrates and liquid-to-solid phase change. The results of this project have the potential of completely eliminating the delay in hydrate formation, and enabling "on-demand" hydrate formation. Results from this research will be integrated into educational activities, which include the development of a graduate level course on Phase Change Heat Transfer and research opportunities for undergraduates and under-represented minorities. This project studies the electro-nucleation of three kinds of hydrates. In the first set of studies, hydrate formation from two immiscible liquids will be analyzed. Cyclopentane hydrate formation will be studied via experiments and analytical modeling to quantify the role of electric fields and interfacial charge on hydrate nucleation. In the second set of studies, hydrate formation from miscible liquids will be analyzed. Tetrahydrofuran hydrate formation will be analyzed to understand the influence of electric current and the resultant bubble generation on nucleation. The third set of studies will analyze electro-nucleation of methane hydrates, wherein hydrates nucleate at a liquid-gas interface at elevated pressures. This project includes nucleation-measurement experiments, analytical multiphysics modeling, and correlation development. Microfluidic cells will be fabricated to obtain statistically meaningful estimates of electro-nucleation. Specific outcomes of this project include measurements of electro-nucleation rates, and an understanding of the physics underlying the formation of various hydrates. This project will highlight the role of electric fields in fundamentally changing the nature of nucleation from stochastic to deterministic. Overall, this research will enable an in depth understanding of the influence of electrical phenomena on micro/mesoscale thermo-fluidic phenomena associated with hydrate formation.