Pressure Drop of Viscoelastic Fluids in the Inlet Region of a Circular Tube

抄録

In order to study the laminar flow behavior of viscoelastic fluids with a high Reynolds number, the pressure distributions in the inlet region of a circular tube were measured by using polymer solutions which were relatively stable at high shear rates. From the results obtained, it was found that the pressure drops of the viscoelastic fluids were appreciably greater than those calculated by the theoretical analysis of the non-Newtonian, inelastic fluids, and also that such greater pressure drops for the viscoelastic fluids could not be explained by the present theory in which the effect of the normal stress is taken into account as the viscoelasticity. It is considered that the disagreement above mentioned is caused by the memory property of the viscoelastic fluids. The pressure distributions were calculated by assuming that the memory effect on the wall shear stress in the inlet region can be given by the first order differential equation.