Dynamics of Air/Water Two-phase Flows in Environmental Hydraulics

了解空气/水两相流动的动力学在包括环境水力学在内的许多科学和工程领域具有重要意义。由于流动的复杂性以及测量设备、计算能力和现场研究的困难，我们在这一领域的知识仍然有限。拟议的研究将利用阿尔伯塔大学现有的优良实验室设施，对水射流在空气中的破碎进行实验研究和数值模拟，并通过将水射流落入水池进行空气卷吸和质量传递。将开展一系列研究项目：(1)针对不同几何形状的单喷流和多喷流，进行水喷流在空气中的破碎研究。测量了水滴破碎后的特性，并对射流破碎过程进行了数值模拟。(2)研究下沉射流在水池中形成的气泡的动力学，测量气水传质的量。这些研究的结果将被推广和发展用于工程用途。(3)将就一种新的工程设计进行额外的探索性研究，以改善氧气和利用水射流防止桥梁在极端洪水事件中坍塌。*拟议的研究将为4名博士生和5名夏季本科生提供极好的培训机会。这项研究将允许开发实用工具，包括用于各种工程应用的数值模型，例如改善大坝溢洪道的设计，以防止气体过饱和和鱼类死亡(即气泡病)，以及下水道系统的通风和气味控制。这项研究还将使我们能够设计有效的注氧系统，以提高河流和湖泊以及废水处理设施中的溶解氧水平。**

Understanding the dynamics of air/water two-phase flows is of fundamental importance in many areas of science and engineering, including environmental hydraulics. Our knowledge in this area is still limited due to the complex nature of flows as well as limitations in measurement devices, computing power and field study difficulties. The proposed study will take advantage of the excellent laboratory facilities available at the University of Alberta to conduct experimental studies and numerical modeling of water jet breakup in air and air entrainment and mass transfer by falling water jet into water pools. A number of research projects will be conducted: (1) Water jet breakup in air will be studied for single jets of different geometries and multiple jets. The characteristics of the water drops after their breakup will be measured, and numerical modeling of the jet breakup process will be conducted. (2) The dynamics of air bubbles in a water pool generated by a plunging jet will be studied, and the amount of air/water mass transfer will be measured. The results of these studies will be generalized and developed for engineering use. (3) Additional exploratory studies will be conducted on a novel engineering design for improving oxygenation and utilizing water jets for preventing bridge collapse during extreme flood events.***The proposed research will provide excellent training opportunities for four PhD students and five summer undergraduate students. This research will allow the development of practical tools including numerical models for various types of engineering applications, such as design improvement for dam spillways to prevent gas supersaturation and fish kill (i.e., bubble diseases), ventilation and odour control in sewer systems. This research will also allow us to design effective oxygen injection system to improve dissolved oxygen levels in rivers and lakes as well as in wastewater treatment facilities. **