Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
Department of Electrical and Computer Engineering, John Hopkins University, Baltimore, MD 21218, USA.
Sensors (Basel). 2020 Mar 17;20(6):1657. doi: 10.3390/s20061657.
There is an increasing need for non-destructive, low-cost devices for real-time fluid viscosity monitoring. Therefore, in this study, a method based on structural health monitoring is adapted for monitoring fluid properties. A device is built such that an inexpensive and disposable viscosity probe be possible. The design incorporates a sensor/actuator pair using a piezoelectric material layered with copper/brass and capable of monitoring viscosity changes in low volume liquids (e.g., vacutainer vial). Experiments performed with the new device show a definite pattern of wave propagation in viscous solutions. A numerical model is built to investigate the wave propagation in the fluid. For experimental measurements, the sensor part of the device detects the generated pressure wave in fluid (e.g., air, water, glycerin) by the actuator part. The phase shift between the actuator and the sensor signals is then recorded and plotted for different concentrations of glycerin and water at room temperature. The results of this study show a direct correlation between the phase shift and varying viscosity in the ultrasonic frequency range from 6 to 9 MHz. The numerical simulation, performed utilizing acoustic modal and harmonic response analysis, results also demonstrate the same trend as the experimental results: a phase shift increases with the viscosity of the fluid.
对于实时流体粘度监测，人们越来越需要非破坏性、低成本的设备。因此，在本研究中，我们采用基于结构健康监测的方法来监测流体特性。我们设计了一种装置，使廉价且一次性的粘度探头成为可能。该设计采用了一对传感器/执行器，使用了带有铜/黄铜层的压电材料，能够监测低体积液体（例如，真空采血管）中的粘度变化。使用新装置进行的实验显示出粘性溶液中波传播的明确模式。建立了一个数值模型来研究流体中的波传播。对于实验测量，设备的传感器部分通过执行器部分检测流体（例如空气、水、甘油）中产生的压力波。然后记录和绘制传感器和执行器信号之间的相位差，以研究不同浓度的甘油和水在室温下的情况。本研究的结果表明，在 6 至 9MHz 的超声频率范围内，相位差与粘度的变化之间存在直接的相关性。利用声学模态和谐响应分析进行的数值模拟也表明了与实验结果相同的趋势：随着流体粘度的增加，相位差也会增加。
