Acoustic viscometer and method of determining kinematic viscosity and intrinsic viscosity by propagation of shear waves

摘要

An acoustic viscometer and method for determining both the kinematic viscosity and the intrinsic viscosity of a liquid which includes an acoustic wave generator, a transmitting piezoelectric transducer, a receiving piezoelectric transducer, and a phase-shift detector. The transmitting piezoelectric transducer is positioned so as to be in contact with the liquid and is operably connected to the acoustic wave generator. The transmitting piezoelectric transducer propagates a longitudinal wave of known frequency through the liquid. The receiving piezoelectric transducer is spaced apart from the transmitting piezoelectric transducer and detects the longitudinal wave and a corresponding shear wave propagated through the liquid. The phase-shift detector is operably connected to both the transmitting and receiving piezoelectric transducers and measures the difference in phase between the longitudinal wave propagated by the transmitting piezoelectric transducer and the longitudinal and shear wave detected by the receiving piezoelectric transducer. The difference in phase is used to determine the velocity of the shear wave, and the kinematic and intrinsic viscosities of the liquid in terms of liquid density.