Measurement of the limiting viscosity with a rotating sphere viscometer



The rotating sphere viscometer is found to be a superior method of measuring the viscosity at zero shear rate of moderately viscous non-Newtonian fluids. The effects of inertia and container walls are studied experimentally. The shear stress-shear rate relationship is found to be linear at the low shear rates studied; thus yielding the limiting viscosity. This measured value of the limiting viscosity can be used in empirical models that are applicable over a wide range.