Abstract: A new method for liquids viscosity measurement is proposed. Magnetostrictive sensor is employed for exciting ultrasonic torsional guided wave in a metal rod probe. The guided wave energy attenuation coefficient measurement model(attenuation model) and velocity measurement model(velocity model) are numerically analyzed. The advantages of attenuation model are highlighted, and the influence of its three parameters including operation frequency, probe material property and rod diameter are investigated. The parameters of the magnetostrictive sensor-based measurement system are optimized to meet the requirements of precisely measuring the liquids with a given viscosity range. The attenuation coefficient of a optimal sensing system must be equal to 1 Np or in the range of 0.5-5 Np. The viscosity of glycerine-water solutions with different concentrations(mass fractions) are measured based on attenuation model. The experimental results are well agreed with the results obtained from traditional measurement method and theoretical model prediction curves. That is, the proposed method can be applied for measuring viscosity of liquids.

Key words: viscosity;ultrasonic guided wave;magnetostrictive sensor