The Effect of Glycerol-Based Suspensions on the Characteristics of Resonators Excited by a Longitudinal Electric Field

Abstract

This study examines the effect of suspensions based on pure glycerol and diamond powder with different concentrations on the characteristics of resonators with a longitudinal electric field. We used two disk resonators made of the quartz and langasite plates with round electrodes on both sides of the plate and resonant frequencies of 4.4 and 4.1 MHz, operating in shear and longitudinal acoustic modes, respectively. Each resonator was mounted on the bottom of a 30 mL liquid container. During the experiments, the container was filled with the suspension under study in such a way that the resonator was completely immersed in the suspension, and the frequency dependences of the real and imaginary parts of the electrical impedance of the resonator were measured. As a result, the shear modulus of the elasticity and shear coefficient of the viscosity of the studied suspensions were determined. The material constants of the suspensions were found by fitting the theoretical frequency dependences of the real and imaginary parts of the electrical impedance of the resonator to the experimentally measured ones, which was calculated using Mason’s equivalent circuit. As a result, the dependencies of the density, shear modulus of elasticity, shear viscosity coefficient, and velocity of the shear acoustic wave on the volume concentration of the diamond particles were constructed.

Determination of Electrical and Mechanical Properties of Liquids Using a Resonator with a Longitudinal Electric Field

“…The main characteristics of piezoelectric resonators include the values of the resonant frequency of the parallel and series resonances and the maximum values of the real parts of the electrical impedance and admittance [20,27]. It is well known that these characteristics strongly depend on the electrical and mechanical parameters of contacting liquid [16,20,[23][24][25][26][27]. Figure 3 (Keysight Technologies, Santa Rosa, CA, USA).…”

“…The main characteristics of piezoelectric resonators include the values of the resonant frequency of the parallel and series resonances and the maximum values of the real parts of the electrical impedance and admittance [20,27]. It is well known that these characteristics strongly depend on the electrical and mechanical parameters of contacting liquid [16,20,[23][24][25][26][27]. Figure 3 The dependences presented in Figure 3 show that with an increase in the conductivity of the liquid from 1.4 to 123 µS/cm, the parallel resonance frequency of the quartz resonator monotonically increases for all "water-glycerol" mixtures.…”

“…For the calculation of the frequency dependencies of the electrical impedance of a piezoelectric resonator without liquid loading, we used the method based on the equivalent electromechanical scheme of Mason [29]. Since this method is described in detail in [27], we provide only brief information here. Using the equivalent scheme of Mason and the pointed above method, the frequency dependences of the real and imaginary parts of the electric impedance of the free resonator were calculated.…”

“…As for the material of the electrodes, we will assume that it is isotropy, and the elastic module and viscosity coefficient can be represented as C 66 e and η 66 e . In this calculation, the above-pointed material constants of quartz and electrodes were taken from the literary sources [27]. Then, in order to determine the true material constant of quartz and electrodes, the calculated frequency dependences of the real and imaginary parts of the electrical impedance were fitted to the experimental ones.…”

“…But, it is obvious that by measuring only one parameter of the resonator, one cannot extract information about the above-mentioned parameters of the liquid. The possibility of the resonators excited by a longitudinal electric field for determining the viscosity coefficient and elastic modulus of a liquid was demonstrated in [27]. It was shown that using these resonators, one can determine the longitudinal and shear elastic modules as well as the longitudinal and shear viscosity coefficients of the suspensions based on glycerol and diamond microparticles.…”