Ultrasonic Characterization of Newtonian and Non-newtonian Fluids

Viscous liquid causes a loss of acoustic energy for acoustic wave propagation through the liquid. From an acoustical point of view, Glycerin being Newtonian is a more complex medium as it is heterogeneous, anisotropic and viscoelastic. Non-Newtonian liquids like PEG-SiO2, DMF-SiO2 solutions show shear-dependent nonlinear Viscosity. Apparent molar adiabatic compressibility ( ), as well as bulk moduli (K) and apparent molar volumes ( ) of different glycerin-water solutions, are evaluated in the present investigation. At the lower concentration region for glycerin-water solutions apparent molar adiabatic compressibility ( ) varies linearly with the independent variable either molality or m1/2. The pulse-echo method has been followed to measure attenuation coefficient and sound velocity in these liquids at room temperature. This sound velocity has been compared with the measurement from high precision density and velocity meter (Anton Paar DSA 5000 M for the same temperature. The measurement technique has been reported to quantify adiabatic compressibility as 10% glycerin in water was found to be 41.1×10-11 Pa-1 (K=2.43GPa) including 1.86dB/cm/MHz of attenuation, less compared to pure water but the ultrasonic absorption coefficient (μa ≈ 0.53) of 10% glycerin in water is nearer to pure water whereas the Non-Newtonian fluids show higher attenuation (>3dB/cm) and higher absorption (μa≈0.6).