Experimental Investigation and Numerical Simulation of Spray Processes

Abstract

Summary: Acoustic levitation was investigated as a model for spray processes. The influence of different parameters on the drying process of aqueous polyvinylpyrrolidone (PVP) solutions was studied and compared to the evaporation of water. The adequacy of acoustic levitation as model for spray processes was demonstrated. Experiments with water and aqueous PVP solutions indicated no dependency of the droplet size on the drying process for droplets with a diameter between 300 mm and 1.5 mm. Particles dried in an acoustic levitator displayed good accordance of morphology with those obtained in a spray tower. Surprisingly the addition of PVP to water resulted in faster evaporation of the solvent. Mathematical models of single droplets within a spray process typically refer to spherically symmetric droplet geometries. The simulation of other morphologies and their evolution throughout the process is still very challenging. A new drying model based on a fully threedimensional meshfree approach is under development and shows good agreement to basic established models regarding the drying of a single droplet.

Southern Ocean Biogeography of Tintinnid Ciliates of the Marine Plankton

“…The first focused studies of Southern Ocean tintinnids date back to material gathered during the German South Polar expedition of 1901-1903. On the basis of the samples gathered, Hans Laackmann first briefly described a few new species of tintinnids (Laackmann 1907) and subsequently produced a monographic study, describing a large number of new species and varieties (Laackmann 1910). He was the first to note that the species "characteristic of the Antarctic," Cymatocylis and species now known as Laackmanniella, had Griffiths (2010).…”

Experimental Investigation of the Morphology Formation of Polymer Particles in an Acoustic Levitator

“…Previous results address the formation of particle morphology of different substances under defined conditions in single droplets ( e.g . aqueous solutions of salts, silica suspensions, aqueous sodium acrylate solutions or N ‐vinyl‐2‐pyrrolidone …”