Flow Prediction of Complex Fluids in a Circular Pipe by Utilizing a Velocity-Profiling-Assisted Rheometer
Kohei Ohie, Taiki Yoshida, Yuji Tasaka, Yuichi Murai
Abstract
Flow prediction of complex fluids in a circular pipe was conducted using a velocity-profiling-assisted rheometer. As application examples, shear-rate-dependent stress and viscosity of carboxymethyl cellulose and polyacrylamide aqueous solutions and rice porridge were evaluated. Carboxymethyl cellulose is a well-known thickener for foods and cosmetics; the latter two examples represent complex fluids that are outside the scope of application of a standard torque-type rheometer because the PAM solution causes shear-localization problems and the porridge includes O(1 mm) size dispersions. The obtained flow curve in shear rate range of O(10–1–101 s–1) was used to predict laminar flow in a pipe under a steady pressure gradient, which is an industrially applicable target. The predicted velocity profiles were in good agreement with experimental results measured in a pilot pipeline, where the maximum relative error of flow rate was less than 10% for all test fluids. This suggests that the application of the rheological evaluation to flow prediction has high industrial practicality to complex fluids which are out of application of the standard rheometer.