Published 12 issues per year
ISSN Print: 1044-5110
ISSN Online: 1936-2684
Indexed in
MEASUREMENT OF THE EVAPORATION RATES OF CLOSELY SPACED FLOWING DROPLETS BY OPTICAL CAVITY RESONANCES
ABSTRACT
The evaporation of liquid droplets in sprays can be altered by interactions between closely spaced particles. We discuss a nonintrusive optical measurement technique that is based on the optical cavity resonances of the droplets to determine droplet sizes and evaporation rates. The addition of small amounts of Rhodamine 6G laser dye into ethanol or ethanol/ acetone mixture droplets allows the droplets to lose at discrete wavelengths that correspond to the spectral positions of the droplet-cavity resonances. Measurements of the cavity resonance shift as the droplet evaporates permits determination of droplet size changes with a sensitivity of 1 nm in droplet radius change for droplets with a radius of 40 μm. We have determined the variation in evaporation rates among the leading and trailing droplets within a single segmented flowing stream, as well as between adjacent droplets that are flowing within a closely spaced 3 × 3 square array of continuous streams. Qualitative fluorescence images of the vapor produced by a continuous single stream of flowing acetone droplets demonstrate the existence of a vapor trail generated by the leading droplets flowing at 10 m/s.
-
Hartings Justin M., Cheung Janice L., Chang Richard K., Temporal beating of nondegenerate azimuthal modes in nonspherical microdroplets: technique for determining the distortion amplitude, Applied Optics, 37, 15, 1998. Crossref
-
Miller R.S., Harstad K., Bellan J., Evaluation of equilibrium and non-equilibrium evaporation models for many-droplet gas-liquid flow simulations, International Journal of Multiphase Flow, 24, 6, 1998. Crossref
-
Horender S., Sommerfeld M., Evaporation of Nearly Monosized Droplets of Hexane, Heptane, Decane and Their Mixtures in Hot Air and an Air/Steam Mixture, International Journal of Spray and Combustion Dynamics, 4, 2, 2012. Crossref
-
Lemoine Fabrice, Castanet Guillaume, Temperature and chemical composition of droplets by optical measurement techniques: a state-of-the-art review, Experiments in Fluids, 54, 7, 2013. Crossref