Magnetic Resonance Imaging of two-phase systems

直接或间接地，人类无时无刻不在遇到气泡和喷雾：通过驾驶柴油车或乘坐公共汽车(柴油喷雾)，通过使用来自水力/热力/核电站的电力(气泡侵蚀水电站涡轮机，是冷却系统中的活性腐蚀剂)，或者通过吃蔬菜(最有可能用杀虫剂喷雾处理)。无论你是设计一个大规模喷洒盐水以对抗全球变暖的地球工程项目，还是建造一个从藻类中生产生物燃料的鼓泡塔反应堆，了解涉及气泡和水滴的过程都是至关重要的。为了加深这种理解，有必要对喷雾中的气泡流动和液滴进行可靠的定量测量。在气泡流和喷雾研究中常用的测量技术是基于光学的。然而，由于气泡和液滴都反射光线，光学技术在高气泡和高喷雾密度下变得无效。该项目建议使用核磁共振成像(MRI)来研究泡状流和喷雾。MRI通常被用作临床诊断手段，由于其作为一种非侵入性的、固有的三维方法的优势，它也正在稳步成为材料研究的基本工具，它可以对各种物理和化学参数敏感，并且不需要任何光学透明度。在鼓泡流中，将开发测量微泡尺寸、流动度和气泡诱导混合的新技术，并在鼓泡塔原型上进行评估。在喷雾研究中，将在核磁共振扫描仪内建立喷雾室。将研究用核磁共振研究液滴蒸发、大小、速度和其他参数的新方法，以便在以前用其他方法无法进入的区域进行极短时间尺度的成像。

Directly or indirectly, humans encounter bubbles and sprays all the time: by driving a diesel car or riding a bus (diesel fuel sprays), by using electricity from hydro/heat/nuclear plants (bubbles erode hydroplant turbines and are active agents of corrosion in cooling systems) or by eating vegetables (most likely treated with insecticide sprays). Whether you design a geo-engineering project to spray salt water on a massive scale to fight global warming or build a bubble column reactor to produce biofuel from algae, an understanding of processes involving bubbles and droplets is of fundamental importance. To develop that understanding, reliable, quantitative measurements of bubbly flows and droplets in sprays are necessary. Commonly employed measurement techniques in studies of bubbly flows and sprays are optics-based. However, as both bubbles and droplets reflect light, optical techniques become ineffective at high bubble and spray densities. This project proposes to use Magnetic Resonance Imaging (MRI) for studies of bubbly flows and sprays. Commonly employed as a diagnostic modality in clinics, MRI is also steadily becoming an essential tool in studies of materials because of its advantages as a non-invasive, inherently 3-dimensional method which can be sensitive to a wide variety of physical and chemical parameters and which does not require any optical transparency. In bubbly flows, new techniques of measuring microbubble sizes, mobility and bubble-induced mixing will be developed and evaluated on bubble column prototypes. In spray research, a spray chamber will be built inside an MRI scanner. New approaches to study droplet evaporation, size, velocities and other parameters with MRI will be investigated, permitting imaging at very short time scales in the regions previously inaccessible by other methods.