ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Fall of Spherical Particles through a Carreau Fluid
P. Doleček, H. Bendová, B. Šiška, and I. Machač
Department of Chemical Engineering, Faculty of Chemical Technology,
University of Pardubice, CZ-532 10 Pardubice
Received: 29 March 2004
Abstract: Numerical solution of Hill’s variational principles is presented for the estimation of upper and lower bounds to the drag coefficient correction function necessary for the determination of terminal velocity of spherical particles falling in purely viscous fluids obeying the four-parameter Carreau viscosity model. Some calculated data of the drag coefficient correction functions are compared with the corresponding experimental data. In the experiments, terminal falling velocities of spheres in aqueous solutions of polyalkylene glycol Emkarox HV 45 doped with a small amount (0.06 mass % and 0.08 mass %) of polyacrylamide Praestol 2935 were measured. At the same time, viscosity function measurements and oscillation dynamic tests of liquids were performed using rheometer RS 150 (Haake).
It was found that due to the liquid elasticity the experimental values Xexp of the drag coefficient correction function are beyond the calculated interval of upper and lower bounds and are higher than the upper bound Xu. However, terminal velocities of spheres falling in the test fluids with similar properties can be roughly estimated using the upper bound Xu for determination of a sphere drag coefficient.
Full paper in Portable Document Format: 586a397.pdf
Chemical Papers 58 (6) 397–403 (2004)