Laminar Flow of Power Law Fluid Foods in Concentric Annuli

摘要

The flow of power law fluids for isothermal, laminar flow in concentric annuli was investigated experimentally and numerically. Similar to the results of Russel & Christiansen (1974, Indust. Engng Chem. Process Des. Develop. 13, 391-398) it was observed that plots of the natural logarithm of a reduced shear stress at the outer wall of the annulus vs the natural logarithm of a reduced pseudo-shear rate were identical to those for tube flow. However, in contrast to the findings of Russel & Christiansen (1974), the y intercepts and the slopes of these plots were found to be equal to In K' and n, respectively. Frederickson & Bird's (1958, Indust. Engng Chem. 50, 347-352) solution was found to be in perfect aggreement with the numerical solution in every case. The Hanks & Larsen (1979, Indust. Engng Chem. Fundamentals, 18, 33-35) equation also agreed very well with the numerical solution. The Russel & Christiansen (1974, Indust. Engng Chem. Process Des. Develop., 13, 391-398) method gave an absolute mean error of 3.6% against the numerical results for pressure drop.