Measurement of Liquid Viscosity and Density Using Single Piezoelectric Resonator with Two Vibration Modes

Abstract

We report the results of an experiment on measuring the viscosities and densities of several liquids using a single piezoelectric sensor, since only the numerical results obtained by finite element analysis were reported in our previous paper. The novelty of the sensor is that the viscosity and density can be inferred simply by measuring resonance frequencies in liquid for the vibration in the tangential and normal directions with respect to the contact surface between the sensor and the liquid, while the method suggested as reference requires measurements of resonance frequency and damping of a single vibration mode. By comparing the viscosities and densities measured by the proposed and conventional methods using food oil, the densities were found to correspond to the values measured using a weight meter with an error within 1% and the viscosity was evaluated to be higher than that measured using a viscometer with an error within 10%. The results suggest the possibility of measuring liquid density and viscosity by the proposed method.