Viscoelastic Flow due to a Rotating Disc Enclosed in a Cylindrical Casing (Numerical Simulation and Experiment)

摘要

Numerical simulations by a finite-difference method have been made for a viscoelastic flow due to a rotating disc enclosed in a cylindrical casing with relatively large axial clearance. The Giesekus model, modified Giesekus model and Phan Thien-Tanner model were applied as the constitutive equations. Using particle tracking velocimetry (PTV), the effects of rheological properties on the distribution of the velocity component V_θ and the secondary flow were clarified. By comparing the experimental results with the numerical simulations the validity of the respective viscoelastic fluid models were examined. The secondary flow pattems observed by flow visualizations were character- ized by the elasticity number (=Weissenberg number/Reynolds number) . It was confirmed experi- mentally that near the rotating axis there was a place where the tangential velocity component was negative for the cases of 0.3 wt and 1 wt polyacrylamide aqueous solutions.