Lamb Wave Sensor for Viscous Fluids Characterization

Abstract

This paper is a study of a new sensor for fluid characterization. This sensor is composed of a stainless steel plate in contact with a viscous material. The aim is to characterize the material viscosity by using reflected Lamb waves at the boundary interface. In order to identify the effects on the Lamb reflected modes by the viscous material, a complete study of the propagation wave in the alone plate is first presented. The propagation modes of the loaded plate are then investigated. By monitoring the mechanical impedance, the viscosity of the material in contact is extracted. In order to validate the experimental setup , the mechanical impedance variation is measured for different water-glycerol mixtures. Results are in good agreement with those obtained by other techniques in the literature.

Dilatational waves at a microstretch solid/fluid interface

“…The reason for this dominance depends on a property of the material called acoustic impedance. The acoustic impedance of a solid material is the product of the density and velocity of dilatational wave, while the acoustic impedance of viscous fluid is given by the square root of the product of density and viscosity (Chancellier et al., 2009).

Figure 1.Variation of reflection coefficient (z1 s) with angle of incidence.

Figure 2.Variation of reflection coefficient (z2 s) with angle of incidence.

Figure 3.Variation of reflection coefficient (z3 s) with angle of incidence.

Figure 4.Variation of reflection coefficient (z4 s) with angle of incidence.

Figure 5.Variation of transmission coefficient (z1 f) with angle of incidence.

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“…The reason for this dominance depends on a property of the material called acoustic impedance. The acoustic impedance of a solid material is the product of the density and velocity of dilatational wave, while the acoustic impedance of viscous fluid is given by the square root of the product of density and viscosity (Chancellier et al, 2009).…”

Piezoelectric Actuated Glass Plate for Liquid Density and Viscosity Measurement

“…It has been shown that Lamb waves are advantageous for stationary mechanical waves generated in liquid media and especially for sensing applications [28,29]. Antisymmetric Lamb waves exhibit a relatively high quality factor in liquid compared to other out-of-plane flexural modes of vibration due to a lower damping in liquid at low frequency [30].…”

PMN-PT based smart sensing system for viscosity and density measurement

“…Lu et al [3] developed out a new method that involves the application of embedded piezoelectric sensors so that monitoring can be determined by analyzing the velocity curves. Wilkie-Chancelie et al [4] designed an innovative sensor that is contacted to the viscous material and employs a reflected Lamb wave at the interface as the index to indicate the viscosity change of the material.…”

“…Piezoelectric-based sensors are considered adaptive for viscosity monitoring due to its quick-response, high-accuracy, and low-maintenance needs. Wilkie-Chancellier et al [4] used a piezoelectric plate as the sensor and applied guided wave (Lamb wave) to monitor the mechanical impedance and then obtain the viscosity of the tested material. This method was found to be valid only when the tested material is a weak fluid, that is, it should have Newtonian properties.…”