AERODYNAMIC ATOMIZATION OF POLYMERIC SOLUTIONS

A helium activated firing device was used to propel viscoelastic fluid slugs (350 cc) to Mach I velocities. Aerodynamic forces disrupt the slug which eventually transforms into a cloud of droplets that fall on the ground below. Various concentrations and types of polymethyl methacrylate (PMM A) in diethylmalonate (DEM) were disseminated. The resultant average drop size for each trial was measured and shown to significantly increase with the addition of polymer. A correlation between average drop size and fluid viscosity was not observed. Both a relative relaxation time deduced from a simple die swell experiment and the first normal stress difference N 1 correlated dissemination trials conducted at ambient temperatures. However, only the relative relaxation time correlation was consistent with breakup trials using heated fluids. Use of N 1 , for predicting particle size from dissemination tests employing heated viscoelastic fluids can produce considerable error.