CORRECTION OF DATA MEASURED WITH A ROTATIONAL VISCOMETER IN THE CASE OF NON-NEWTONIAN LIQUIDS

Abstract

Newtonian and non-Newtonian substances were investigated with a rotational viscometer, featuring cylinder pairs of different radius ratio. Flow-curves calculated· from the torque-angular speed data measured with the generally used relationship, valid only for Newtonian liquids, did not coincide for non-Newtonian liquids in the case of different cylinder pairs, and the deviation of the curves was the larger, the more the behaviour of the liquid differed from the Newtonian behaviour. Transforming data with Krieger-Elrod's [7] equation, the points measured with different cylinder pairs were lying along a common flow curve.