Dual-plane ultrasound flow measurements in liquid metals
Dual-plane ultrasound flow measurements in liquid metals
复制标题
液态金属中的双平面超声波流量测量
DOI：
10.1088/0957-0233/24/5/055302
复制
发表时间：
2013
影响因子：
2.4
通讯作者：
J. Czarske
中科院分区：
文献类型：
--
作者：
L. Büttner;R. Nauber;M. Burger;D. Räbiger;S. Franke;S. Eckert;J. Czarske
提出了一种用于双平面、双分量流速测量（特别是在不透明液体中）的超声测量系统。目前用于测量不透明液体中的局部流动结构的技术公开了关于单个超声探头的线性测量的相当大的缺点。为了研究随时间变化的流动模式，传统的超声技术要么受到耗时的机械移动的限制，要么受到单个探头的顺序操作的限制。本文介绍的测量系统采用四个传感器阵列，总共 100 个单个元件，无需机械移动即可进行流量测绘。由于使用基于微控制器的电子开关矩阵实现的时分复用的高效并行化方案，已经实现了几个 10 Hz 的高帧速率。测量系统的功能和性能通过旋转磁场 (RMF) 驱动的立方体内室温下的液态金属流动进行了演示。首次使用具有两个交叉测量平面的配置对一次流和二次流进行了详细且同时的研究。实验数据证实了数值模拟的预测。 RMF 突然打开后，通过帧速率为 3.4 Hz 的时间分辨测量来观察二次流的惯性振荡。实验表明，所提出的测量系统能够研究不透明液体中复杂和瞬态的流动结构。由于其能够研究局部流动结构随时间的演变，该测量系统可以为流体动力学研究提供相当大的进展，特别是在食品工业或液态金属技术中的应用。
An ultrasound measurement system for dual-plane, two-component flow velocity measurements especially in opaque liquids is presented. Present-day techniques for measuring local flow structures in opaque liquids disclose considerable drawbacks concerning line-wise measurement of single ultrasound probes. For studying time-varying flow patterns, conventional ultrasound techniques are either limited by time-consuming mechanical traversing or by the sequential operation of single probes. The measurement system presented within this paper employs four transducer arrays with a total of 100 single elements which allows for flow mapping without mechanical traversing. A high frame rate of several 10 Hz has been achieved due to an efficient parallelization scheme using time-division multiplexing realized by a microcontroller-based electronic switching matrix. The functionality and capability of the measurement system are demonstrated on a liquid metal flow at room temperature inside a cube driven by a rotating magnetic field (RMF). For the first time, the primary and the secondary flow have been studied in detail and simultaneously using a configuration with two crossed measurement planes. The experimental data confirm predictions made by numeric simulation. After a sudden switching on of the RMF, inertial oscillations of the secondary flow were observed by means of a time-resolved measurement with a frame rate of 3.4 Hz. The experiments demonstrate that the presented measurement system is able to investigate complex and transient flow structures in opaque liquids. Due to its ability to study the temporal evolution of local flow structures, the measurement system could provide considerable progress for fluid dynamics research, in particular for applications in the food industry or liquid metal technologies.