Non-Newtonian viscosity measurements in the intermediate shear rate range with the falling-ball viscometer

摘要: Abstract An attempt to use the falling-ball experiment measure non-Newtonian viscosity in intermediate shear rate range was successfully accomplished by combining direct experimental observations with a simple analytical model for average and at surface of sphere. The data aqueous solutions Carbopol-960, carboxymethyl cellulose, polyethylene oxide polyacrylamide obtained from viscometer gave good agreement those other viscometers, confirming general applicability approach. In experiments highly viscoelastic terminal velocity observed be dependent on time interval between dropping successive balls. This time-dependent phenomenon used determine characteristic diffusion times concentrated polyacrylamide. These values were, turn, compared characteristics relaxation determined Powell-Eyring model. program revealed that has very limited utility measurement steady polymer solutions.