Elastic Turbulence Effects on the Performance of a Miniature Viscous Disk Pump

Within the present investigation, a miniature viscous disk pump (VDP) is utilized to characterize and quantify non-Newtonian fluid elastic turbulence effects, relative to Newtonian flow behavior. Such deviations from Newtonian behavior are induced by adding polyacrylamide to purified water. The VDP consists of a 10.16 mm diameter disk that rotates above a C-shaped channel with inner and outer radii of 1.19 mm, and 2.38 mm, respectively. A channel depth of 230 μm is employed. Fluid inlet and outlet ports are located at the ends of the C-shaped channel. Within the present study, experimental data are given for rotational speeds of 1200–3500 rpm, pressure rises of 0 to 700 Pa, and flow rates up to approximately 0.00000007 m³/sec. As such, the overall intent is enhancement of fundamental understanding of the associated physical processes associated with elastic turbulence, as it is induced in liquids by polymers subject to stretching and constriction by flow strain. Different amounts of flow strain are induced by changing the rotational speed of the disc. As rotational speed increases, overall magnitudes of flow strain increase, and the polymer strings become locally more agitated. The result is growth in the local elastic stress, and development of the Weissenberg instability as the Weissenberg number increases. Overall consequences include increased mixing, increased transport levels, and larger static pressure rise magnitudes. Also considered are changes to effective viscosity from the presence of elastic turbulence.