Ultrasonic particle scrubbing with drops.

1336632PI：Sayor这个项目是研究如何结合使用超声波和喷雾来提高对微米级颗粒的清除能力。在污染控制和矿山粉尘控制等应用中，喷雾被广泛用于降低空气中的颗粒物水平。然而，使用喷雾剂很难将微米级的颗粒物从空气中去除，因此即使在大力喷洒的情况下，这些微米级的颗粒物仍然存在。当声波与物体相互作用时，就存在声辐射力。在这项工作中，来自超声波的声辐射力被用来迫使颗粒和水滴相互接触，从而从空气中清除或清除这些颗粒。其目标是对微米级的颗粒进行更大程度的清除，而不是使用超声波。关于声辐射力有几种理论，但这些理论之间有很大的分歧。这是一个重要的问题，因为在没有理论的情况下，任何利用声学来改进颗粒清除的尝试都将被迫依赖于耗时的试验和错误方法。因此，这个项目的第一步是通过实验验证和修正理论。这本身就将是一个重大的结果。这一结果也将被用来指导该项目的进一步实验，以展示如何最好地利用超声波改进喷雾对微米级颗粒的清除。该项目的一个特别重要的目标将是确定是否应将声辐射力配置为同时作用于颗粒和液滴，迫使它们进入一个小区域，从而增加对颗粒的清除，或者替代地(或另外)使用声辐射力使颗粒相互结合，使它们更容易被移除。大约一微米大小的颗粒(大约是人类头发直径的五分之一)对人类的肺部健康非常危险。这令人担忧有两个原因。首先，在这个范围内的颗粒很难被人体排斥。大于一微米的颗粒往往会被阻塞在咽部和上呼吸道系统，而小于一微米的颗粒在进入肺部后可能会被呼出。然而，直径约一微米的颗粒往往会一直进入我们肺的肺泡区，然后停留在那里。水喷雾通常用来帮助消除空气中的颗粒物。例如，被称为湿式洗涤器的装置被用于烟囱，以降低颗粒污染物的水平。然而，由于技术原因，水喷雾不太擅长去除尺寸在微米量级的颗粒，这导致了第二个令人担忧的问题，即喷雾擅长去除远大于或小于微米的颗粒，而不是微米量级的颗粒。因此，微米大小的颗粒物会导致肺损伤，喷雾剂不能很好地将它们挡在我们呼吸的空气之外。在这个项目中，超声波(声波在人类听力范围之外)被用来提高喷雾确实从空气中去除颗粒物的能力。通过使用高强度超声波，颗粒和喷雾液滴可以被推到彼此非常接近的位置，使液滴能够以一种原本不会发生的方式去除危险的颗粒。这项工作的潜在重要性在于，它可能会在烟囱、汽车和卡车排气系统、采矿车辆的驾驶室以及地下矿山中实施。这样，该项目开发的技术可能被用来降低空气中的颗粒物水平，从而降低哮喘、肺癌和慢性阻塞性肺病等肺部疾病的发生率。

1336632PI: Saylor This project is an investigation of how ultrasonics and sprays can be used together to improve the scavenging of micron-scale particles. Sprays are widely used to reduce the level of particles in air in applications such as pollution control and dust control in mines. However micron scale particles are very difficult to remove from the air using sprays, and so significant levels of these micron scale particles exist even when sprays are vigorously implemented. An acoustic radiation force exists whenever a sound wave interacts with an object. In this work the acoustic radiation force from ultrasonic waves is used to force particles and drops to come into contact with each other thereby scavenging, or removing, these particles from the air. The goal is to cause greater scavenging of micron-scale particles than would have existed without the use of ultrasonics. Several theories for the acoustic radiation force exist, however there are significant disagreements between these theories. This is a significant issue, since without a theory, any attempts to improve the scavenging of particles using acoustics will be forced to rely on a time-consuming trial and error approach. Accordingly, the first step in this project is to experimentally validate and correct a theory. This will be a significant result in and of itself. This result will also be used to guide further experimentation in this project to show how to best improve scavenging of micron-scale particles by sprays using ultrasonics. An especially important goal of this project will be to determine if the acoustic radiation force should be configured to act on both particles and drops, forcing them into a small region, thereby increasing the scavenging of particles, or alternatively (or in addition), to use the acoustic radiation force to make the particles combine with each other, causing them to more easily be removed. Particles that are on the order of one micron in size (about one-fiftieth of the diameter of a human hair) are very dangerous to the pulmonary health of human beings. This is of concern for two reasons. Firstly, particles in this range are very difficult for the human body to reject. Particles larger than a micron tend to be blocked in the pharynx and upper respiratory system, while particles much smaller than a micron may be exhaled after entering the lung. However, particles that are about one micron in in size tend to make it all the way into the alveolar region of our lung, and then stay there. Water sprays are often used to help eliminate particles from the air. For example, devices called wet scrubbers are used in smokestacks to reduce the level of particulate pollutants. However, due to technical reasons, water sprays are not very good at eliminating particles that have a size on the order of a micron, leading to the second point of concern which is that sprays are good at removing particles that are much larger than or much smaller than a micron, but not those on the order of a micron. Hence, micron size particles can cause lung damage, and sprays are not very good at keeping them out of the air that we breathe. In this project, ultrasonic sound waves (acoustic energy just outside of the range of human hearing) are being used to improve the ability of sprays do remove particles from the air. By using high intensity ultrasound, particles and spray drops can be pushed into close proximity to each other, enabling the drops to remove the dangerous particles in a way that would not otherwise occur. The potential importance of this work is that it may be implemented in smoke stacks, automobile and truck exhaust systems, the cabs of mining vehicles, and in underground mines. In this way, the technology developed in this project may be used to reduce the level of particles in the air, thereby reducing the incidence of lung ailments such as asthma, lung cancer and COPD.