Determination of Effective Shear Rates in Rotational Viscometers With Complex Geometries

The effective shear rates of a flag and a star shaped impeller were determined in a jacketed vessel by matching the viscosity of a Newtonian fluid and the apparent viscosity of a non‐Newtonian fluid, and from the slope of a plot of (1–n) versus log (P/K N n+1 d 3 ). The results from the two methods were in good agreement. For geometries with large surface areas, the method of matching viscosities is less likely to contribute to errors.