Particle Dispersion in Turbulent Sprays
Abstract
A scheme was devised to inject individual tagged droplets into a turbulent spray. The droplets were tagged with a laser dye. The bulk of the spray in the jet was created with micro air blast atomizers that formed an aerosol with a narrow size distribution. Particle Imaging Velocimetry (PIV) was implemented with a novel solid state high voltage switch to control the Pockel cell of a YAG laser. The PIV results showed that the micro atomizers yielded well behaved initial conditions for the spray. Dispersion measurements of a tagged fluorescent droplet indicated that the spray had an impact on the dispersion phenomenon if any swirl were imparted to the flow; with precisely aligned injectors the effect of the spray on particle dispersion was very small, suggesting that the turbulence modulation was not important under well controlled conditions. Droplet Lasing Spectroscopy was applied successfully to measurements of vaporization rates of droplets in non-reacting and in burning droplet streams. The results represented a significant extension of the lasing principle to more realistic spray conditions. Instantaneous vaporization rates were measured in a burning droplet stream where the technique was found to yield accurate data. A particle Large Eddy Simulation (PLES) sub model was implemented into a hybrid spectral finite difference solution procedure for the Navier Stokes equation. A semi-analytical Poisson solver was established that was accurate and fast. The PLES method showed encouraging results in jet simulations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 08, 1998
- Accession Number
- ADA358486
Entities
People
- Ian M. Kennedy
- Wolfgang Kollmann
Organizations
- University of California, Davis