AXIAL FLOW IN A ROTATIONAL COAXIAL RHEOMETER SYSTEM 11: HERSCHEL BULKLEY MODEL

Following recent works of several authors like Huilgol, Bhattacharya etd. and Javadpour et al., this paper is to contribute further to the literature of axial flow in a rotational coaxial rheometer. We consider axial flow of Herschel Bulkley mode1 between two concentric cylinders with the inner one rotating, while the outer cylinder is held stationary. An attempt has been made to direct the analysis toward an examination of the relationship between moment (M) and angular velocity ( ) at the inner cylinder. The radial dependence of the shear stress and viscosity follows directly by our mathematical analysis with a simple numerical procedure. We describe the relationship between shear stress and shear rate and the dependence of these on axial flow rate in the annular region, for power law and Herschel Bulkley fluids