Evaporation Behavior Of Droplets Research Articles

HEAT AND MASS TRANSFER MODELING OF SUBMICROMETER DROPLETS UNDER ATMOSPHERIC PRESSURE CONDITIONS

The mathematical modeling of heat and mass transfers of submicrometer droplets vaporizing in gaseous surroundings at atmospheric pressure is investigated, including the effect of equilibrium/nonequilibrium assumption at the liquid/gas interface and of surface curvature on the droplet evaporation behavior. The numerical limitations of some of the most frequently used models for academic and industrial research activities on sprays have been enlightened. Emphasis is given to the verification of the validity of the assumptions imposed when they are extrapolated outside the range of operating conditions within which they have been derived, for instance, when they are used to predict the heat and mass transport phenomena occurring in submicrometer aerosol particles.

Broadband Mie scattering from optically levitated aerosol droplets using a white LED

We describe a simple and efficient means of using a white LED source to illuminate an optically levitated aerosol droplet to enable study of broadband Mie scattering. The backscattered resonances are imaged through a spectrograph and CCD which show high resolution Mie scattering intensity distributions across a spectral range of 480 to 700 nm. The wide spectral range allows assignment of resonance mode numbers and mode orders using conventional Mie theory calculations. Accurate droplet sizing, within +/- 2 nm, is possible for water-based droplets with radii between 2 microm and 8 microm. We additionally demonstrate that the refractive index dispersion can be determined from a single refractive index value at known wavelength. Finally, morphological droplet dynamics are presented showing non-linear droplet evaporation behaviour at a temporal resolution of 100 milliseconds.