气泡体积监测气泡速度监测

The ABS Acoustic, Bubble Spectrometer ®© is an acoustics based device that measures bubble size 

distributions and void fraction of bubbles in liquids. The initial efforts to develop the technology were funded by the National Science Foundation. Continued developments were funded by institutions and companies in both public and private sectors, including Department of Energy, Oak Ridge National Laboratories, and many other companies. The ABS Acoustic Bubble Spectrometer®© is under constant development, driven by new applications and by the request of customers using the instrument to address their specific applications.

ABS声学气泡监测仪（可用于监测气核）是用以监测液体中气泡的体积数密度分布和含气率的声学原理设备。该项科技最初由美国国家科学基金会投资，后续则得到了美国国家能源部和橡树岭国家实验室，以及其他企业的支持。在越来越多的应用和客户需求的驱动下，ABS声学气泡监测仪仍在不断地更新，用以解决客户的特定应用问题。

（设备简图，注：不含电脑）                   （监测高压过程的水听器）

Principle : 

原理：

The device extracts the bubble population from acoustical measurements made at several frequencies. It consists of a set of two transducers/hydrophones connected to a computer. A data acquisition board controls the hydrophones' signal generation and acquisition. The PC is also used for analysis of the data and provides, using Dynaflows software, the sound speed and attenuation as a function of frequency.

该设备从多组频率的声学测量中提取出气泡的数量。它由一组连接到计算机的两个传感器/水听器组成。一个数据采集装置会控制水听器的信号生成和获取。依托Dynaflow软件，以声音的速度和衰减作为频率的函数，电脑被用于分析和展示数据，

The bubble population can be obtained from these measurements by a solution of two Fredholm Integral Equations of the first kind. These equations are ill-posed and are a challenge to solve - especially when the data has noise. In our research, we developed novel algorithms that are able to accurately solve these equations using a constrained optimization technique.

通过解两种Fredholm积分方程，可以从这些测量中得到气泡的数量。这些方程式是不适定的，当数据有噪音的时候，获得结果更是一个挑战。在我们的研究中，我们开发了一种新的算法，能够利用约束优化精确地求解这些方程

The instrument can provide the data in near real time, thus making it suitable for process applications. The bubble distributions from the ABS Acoustic Bubble Spectrometer®© have been validated by comparison with micro-photography.

该仪器可以实时提供数据，从而使其适合于过程应用。并通过与微摄像技术，对比验证了ABS声学气泡监测仪的气泡体积数密度分布结果。

（系统简图）

Advantages:

优势

Compared to optics based devices, ABS Acoustic Bubble Spectrometer ®© is easy to use. In addition, the acoustic technique is very sensitive to bubbles and is not fooled by the presence of particulate matter which are not readily distinguishable from optics.

与光学设备相比，ABS声学气泡监测仪更易于使用。此外，声学技术对气泡非常敏感，并且不会被颗粒物质的存在所干扰，这些物质以光学手段并不容易区分。

Applications:

应用

The device can be used in a wide variety of two-phase flow applications where knowledge of the bubble size distribution and the volume fraction and/or area of contact between the gas and the liquid is important. Major areas of application are in oceanography, controlled laboratory testing, and industrial flows. Possibilities for further application are in the field of bio-medical instrumentation.

该装置可广泛应用于各种两相流应用，尤其是在需要了解气泡体积数密度分布和气体与液体的体积分数和/或接触面积的应用中。应用的主要领域是海洋学、受控实验室检测和工业流动。进一步还有可能应用在生物医学仪器领域。

Aeration:

曝气：

Bubble counting has potential uses in monitoring aeration in areas such as sewage treatment. Another potential use is in the area of fish farming, where fish species can be categorized by the size of their swim bladders. Use of the present acoustic techniques would permit measurement of the numbers and size of fish in a given volume.

在污水处理等领域，气泡计数有其潜在的用途。另一种可能的用途是在鱼类养殖领域，在那里，鱼种可以根据鱼鳔的大小来分类。利用现有的声学技术，可以测量给定体积内鱼类的数量和大小。

Oceanography:

海洋学

Gas bubbles are generated in large numbers in the upper ocean layers, and have a significant effect on ocean acoustic properties. Bubbles strongly modify the sound speed and make the ocean acoustically dispersive. The modeling of the ambient sound-spectrum in the ocean requires the bubble size distribution as input. Knowledge of the amount and location of gas exchange is also required in ocean-atmospheric studies including the carbon-cycle, study of the balance of greenhouse-gases, the oxygenation of oceans and its role in the food-chain, etc.

气泡在上层海洋中大量产生，对海洋声学特性有显著的影响。气泡显著地改变了声音的速度，使海洋在声学上分散了。海洋中环境声谱的建模要求气泡大小的分布作为输入。在海洋大气研究中也需要了解气体交换的数量和位置，包括碳循环，研究温室气体的平衡，海洋的氧化作用以及它在食物链中的作用等等。

Cavitation and Multiphase Flow:

空化与多相流

Micro-bubbles act as nuclei for cavitation inception. Cavitation is a process in which cavities grow and implode violently in a liquid, occur in flows following a pressure drop, or in the presence of an acoustic field. Cavitation has a strong erosive effect on nearby boundaries such as valves, gates, pumps, propellers and fluid-machinery, and is a significant noise source. Knowledge of the sizes of bubbles in a medium along with knowledge of the flow/sound-field can be used to predict the likelihood of cavitation and provide important information for improving design. Naval architects now require information on bubble population under field conditions for the design of propellers so that conditions in the field can be related properly to conditions in the laboratory. Cavitation tunnels as well as turbine and power plant equipment users, which perform measurement of void-fraction/bubble population to determine optimal and safe operating conditions, should thus find use for the device.

微气泡是空化现象的核心。空化是一种过程，在这种过程中，空化气泡在液体中的生长和溃灭，会在压力下降后发生，或在声场出现时发生。空化对附近的边界有很强的侵蚀作用，如阀门、门、泵、螺旋桨和流体机械，并且是一个重要的噪声源。了解介质中气泡大小的知识和了解流动/声场的知识，可用于预测空泡的可能性，并为改进设计提供重要的信息。海军建筑师现在要求在现场条件下的气泡数量，以设计螺旋桨，以便该现场的条件能够与实验室条件相吻合。空化隧道以及涡轮和电厂设备用户，通过对空分/气泡数量的测量来确定合适、安全的操作条件，从而为设备找到合适的使用方法。