A new instrument to perform simultaneous measurements of density and viscosity of fluids by a dual vibrating-wire technique

Abstract

A preliminary presentation of a new vibrating-wire instrument for the simultaneous measurement of the viscosity and density of fluids, over wide ranges of temperature and pressure, is made. The new equipment has the capability of measuring modes of oscillation, either in a forced mode or free decay. A theoretical description of both modes enables the simultaneous measurement of the viscosity and density of the fluid, either from an analysis of the resonance curve, or the transient response of the sensor. The consistency of the two approaches, under the same working conditions, and quality of the measuring system, have been assessed with toluene as the test fluid. It is concluded that the new equipment improves the forced mode of operation described earlier and adds a new flexibility to the vibrating-wire method.