Elongational response of viscoelastic fluids in tubeless-siphon experiment

Abstract

The tubeless-siphon (Fano) flows of four solns. of polyacrylamide (PAA Dow Separan AP - 30), viz. 0.6, 0.8, 1.0, 1.2% in 50/50 mixts. by wt. of glycerin and water are exptl. studied. A tubeless-siphon app. has been set up to evaluate elongational flow. The test fluid is sucked up into a nozzle by a vacuum system. A two dimensional momentum balance involving the free-surface geometry is applied with inertia effects included in the anal. Free-body diagrams for the nozzle holder and the fluid are considered to relate the applied external force to the total stress tensor components; various forces could be applied and measured. The velocity profile may be obtained by means of photographing the fluid column and measuring the flow rate. To consider the effect of nozzle diam., two nozzles are used. Data of liq.-column profile and computed elongational viscosity based on the anal. using exptl. results are given graphically. [on SciFinder (R)]