PLIF IMAGING OF FUEL-VAPOR SPATIAL DISTRIBUTION AROUND A MONODISPERSE STREAM OF ACETONE DROPLETS: COMPARISON WITH MODELING

摘要

Planar laser-induced fluorescence measurements of fuel-vapor concentration around a monodisperse stream of acetone droplets is presented. Droplets were injected in a confinement at different temperatures and the influence of parameters such as droplet diameter, droplet spacing, and temperature of the surrounding gas on droplet evaporation were characterized. Radial and axial profiles of fuel-vapor concentration were obtained for different experimental conditions, and results indicate that the spatial distribution of fuel vapor around droplets depends on the aforementioned parameters. The halation phenomenon is identified as a potential bias for fuel-vapor measurements in the vicinity of droplets and a strategy is proposed to prevent its influence. The application of the technique for fuel-vapor measurements in real sprays is also discussed. Experiments were compared with different simplified theoretical droplet evaporation models. Numerical results show the necessity of including corrections for forced convection and droplet spacing in the droplet evaporation modeling and also the need to consider the variation of gas-phase velocity with radial distance to droplets.