An ultrasonic shear wave viscometer for low viscosity Newtonian liquids

S Mastromarino,R Rook,D De Haas,E D J Verschuur,M Rohde,J L Kloosterman

doi:10.1088/1361-6501/ac200f

S Mastromarino, R Rook + Show 4 more

Open Access

https://doi.org/10.1088/1361-6501/ac200f

Copy DOI

Abstract

A method based on ultrasonic wave propagation is applied for the determination of the viscosity of low viscous liquids. A waveguide is used to remotely transmit the ultrasonic waves from a shear piezoelectric transducer into the liquid. At the solid–liquid interface, a guided wave mode, the shear mode, is used to extract the liquid viscosity. The energy of the reflected ultrasonic wave depends upon its operating frequency, the physical properties of the liquid (viscosity and density), and the waveguide (density and shear modulus). The results show that the attenuation of the waves, and thus the viscosity of the liquid, can be retrieved using this method. Measurements on water, ethanol, and mixtures of water/glycerol illustrate that the method can monitor changes in attenuation due to the viscosity of the liquid. The range of viscosities measured was between 0.8 and 60 mPa s. Compared to literature values, the relative error for these measurements was lower than 12% while the uncertainty in the measurements was lower than 5%. Besides its ability to measure low viscosities, this method offers advantages such as the capability to perform in-situ measurements of liquids in harsh environments, the omission of mechanical parts, and the possibility to handle small volumes of liquid. These features make this method suitable for low viscous liquids that are radioactive, corrosive and at high temperature.

Highlights

In many industrial applications one can find low viscosity liquids in harsh environments, such as high temperatures, high corrosion or high radioactivity
The advantage of using this falling ball viscometer is that a reference viscosity for the liquids can be obtained at the same time, under the same conditions, and with exactly the same composition as the viscosity measurements with the ultrasonic waveguide
The technique based on ultrasonic wave propagation for deriving the viscosity of liquids is a promising technique for measuring a wide range of low viscosity liquids between 0.8 and 60 mPa s

Summary

Introduction

In many industrial applications one can find low viscosity liquids in harsh environments, such as high temperatures, high corrosion or high radioactivity. The usage of ultrasound for measuring material properties started in 1949 with Mason et al who placed the transducer in direct contact with the liquid [1]. This is, not possible for measuring corrosive liquids that can destroy the piezoelectric element in the transducer. The principle used for evaluating the viscosity of liquids is based on a high frequency wave that is transmitted in a solid guide and attenuated by the shear motion within the liquid in which the guide is immersed. Shear stresses do not exist and only longitudinal waves can be transmitted [17]. When the plate is immersed in a viscous liquid, shear stresses may appear as well in the surrounding liquid and the guided waves, both longitudinal and shear, propagating in the plate can be attenuated due to viscous dissipation [10]

Methods

Results

Conclusion