Greenwood Margaret Stautberg, Bamberger Judith Ann
Pacific Northwest National Laboratory, Richland, WA 99352, USA.
Ultrasonics. 2002 Aug;39(9):623-30. doi: 10.1016/s0041-624x(02)00372-4.
An on-line sensor to measure the density of a liquid or slurry, based on longitudinal wave reflection at the solid-fluid interface, has been developed by the staff at Pacific Northwest National Laboratory. The objective of this research is to employ shear wave reflection at the solid-fluid interface to provide an on-line measurement of viscosity as well. Both measurements are of great interest for process control in many industries. Shear wave reflection measurements were conducted for a variety of liquids. By analyzing multiple reflections within the solid (only 0.63 cm thick-similar to pipe wall thickness) we increased the sensitivity of the measurement. At the sixth echo, sensitivity was increased sufficiently and this echo was used for fluid interrogation. Shear wave propagation of ultrasound in liquids is dependent upon the viscosity and the shear modulus. The data are analyzed using the theory for light liquids (such as water and sugar water solutions) and also using the theory for highly viscous liquids (such as silicone oils). The results show that, for light liquids, the shear wave reflection measurements interrogate the viscosity. However, for highly viscous liquids, it is the shear wave modulus that dominates the shear wave reflection. Since the density is known, the shear wave velocity in the liquid can be determined from the shear wave modulus. The results show that shear wave velocities in silicone oils are very small and range from 315 to 2389 cm/s. Shear wave reflection measurements are perhaps the only way that shear wave velocity in liquids can be determined, because the shear waves in liquids are highly attenuated. These results show that, depending on the fluid characteristics, either the viscosity or the shear wave velocity can be used for process control. There are several novel features of this sensor: (1) The sensor can be mounted as part of the wall of a pipeline or tank or submerged in a tank. (2) The sensor is very compact and can be located within the process stream. (3) The sensor can interrogate and characterize very attenuative liquids or slurries because the sensor operation depends upon reflection at the interface between the solid and the fluid, rather than on transmission through a liquid. (4) The sensor performance is not affected by fluid flow rate, entrained air, or vibration.
太平洋西北国家实验室的工作人员开发了一种基于固体 - 流体界面处纵波反射来测量液体或浆液密度的在线传感器。本研究的目的是利用固体 - 流体界面处的剪切波反射来实现粘度的在线测量。这两种测量对于许多行业的过程控制都非常重要。对多种液体进行了剪切波反射测量。通过分析固体（仅0.63厘米厚，类似于管壁厚度）内的多次反射，我们提高了测量的灵敏度。在第六次回波时，灵敏度得到了充分提高，并且该回波被用于流体检测。超声在液体中的剪切波传播取决于粘度和剪切模量。使用轻液体（如水和糖水）的理论以及高粘性液体（如硅油）的理论对数据进行了分析。结果表明，对于轻液体，剪切波反射测量可检测粘度。然而，对于高粘性液体，主导剪切波反射的是剪切波模量。由于密度已知，液体中的剪切波速度可由剪切波模量确定。结果表明，硅油中的剪切波速度非常小，范围在315至2389厘米/秒之间。剪切波反射测量可能是确定液体中剪切波速度的唯一方法，因为液体中的剪切波会高度衰减。这些结果表明，根据流体特性，粘度或剪切波速度均可用于过程控制。该传感器有几个新颖的特点：（1）传感器可作为管道壁或罐体壁的一部分安装，或浸没在罐体内。（2）传感器非常紧凑，可放置在工艺流程中。（3）该传感器可检测和表征高度衰减的液体或浆液，因为传感器的操作取决于固体与流体界面处的反射，而不是通过液体的传输。（4）传感器性能不受流体流速、夹带空气或振动的影响。
