Characterizaton of Spray-Drying Nozzles at Industrially Relevant Conditions

Publication Reference: 
Author Last Name: 
Nasser Ashgriz, Siyu (Jerry) Chem, Isaac Jackiw
Report Type: 
Research Area: 
Particle Formation
Publication Year: 

Executive Summary

This project sought to develop physically realistic models for atomization processes relevant to particle

production, such as in spray-drying processes, with a focus on high viscosity and non-Newtonian fluid

atomization. The goals of this work were to generate a spray database and to develop understanding and

correlations for the accurate pilot-to-production scaleups. We divided the work to focus on two nozzle

types: pressure-swirl, and two-fluid nozzles. The followings were achieved in the present reporting period.

Database was generated for two pilot scale nozzles.

• Droplet size distributions and near-nozzle images are obtained for the two pilot scale nozzles.

• Water (inviscid fluid), glycerin/water solution (Newtonian fluid), CMC/water solution (non-

Newtonian polymeric fluid) are used as test fluids.

• Mass flow rate, spray angle and liquid sheet breakup lengths are measured for each case.

• Droplet size distributions are measured at 80mm downstream from the nozzle exit.

• Near nozzle images are taken from the nozzle exit to where the ligaments are formed.

Pressure-swirl nozzles: The following correlation is developed for high viscosity fluids.

For high viscosity and polymeric fluids, increasing the orifice diameter can result in a decrease in SMD.

The droplet size distribution of high viscosity and polymeric fluids has a bimodal distribution, with a minor

and a major peaks (modes). A mixture of two lognormal distributions fits the volume distribution of all

testing conditions. The minor peak (mode) of the size distribution represents the long tail of the volume

distribution and it corresponds to droplets of less than 10 μm. These small droplets are mainly generated