Ultrasonic methods for measuring liquid viscosity and volume percent of solids

Abstract

This report describes two ultrasonic techniques under development at Argonne National Laboratory (ANL) in support of the tank-waste transport effort undertaken by the U.S. Department of Energy in treating low-level nuclear waste. The techniques are intended to provide continuous on-line measurements of waste viscosity and volume percent of solids in a waste transport line. The ultrasonic technique being developed for waste-viscosity measurement is based on the patented ANL viscometer. Focus of the viscometer development in this project is on improving measurement accuracy, stability, and range, particularly in the low-viscosity range (<30 cP). A prototype instrument has been designed and tested in the laboratory. Better than 1% accuracy in liquid density measurement can be obtained by using either a polyetherimide or polystyrene wedge. To measure low viscosities, a thin-wedge design has been developed and shows good sensitivity down to 5 cP. The technique for measuring volume percent of solids is based on ultrasonic wave scattering and phase velocity variation. This report covers a survey of multiple scattering theories and other phenomenological approaches. A theoretical model leading to development of an ultrasonic instrument for measuring volume percent of solids is proposed, and preliminary measurement data are presented.