Development of extensional viscosity measurement method on low viscos polymer solution with an abrupt contraction flow

Polymer solution shows complex behaviors, which are merits and demerits in industries. For a molding process, a fiber spinning process and a turbulent drag reduction system, concentrated or dilute polymer solutions are used. In these processes, characteristics of extensional viscosity should be important. For example, increments of extensional viscosities due to polymers are considered as one of the reasons for the drag reduction occurrence. In this study, we propose a simple technique to measure the extensional viscosity of Newtonian and non-Newtonian fluids in abrupt contraction flows. The abrupt contraction flow was realized by connecting a syringe and a thin glass tube under a polarizing microscope. The syringe was filled with Newtonian and non-Newtonian fluids, and a syringe driver control to push the fluids out. The force to push the syringe was measured by a load cell to calculate the pressure added to the flow. Extensional viscosity was calculated by considering the pressure losses in the abrupt contraction flows. Water was measured as a Newtonian fluid, and polymer solution was measured as a non-Newtonian fluid. Extensional viscosity of the polymer solution measured in this study qualitatively shows the reasonable characteristics. © 2013 The Japan Society of Mechanical Engineers.