Collision of a vortex with a vaporizing droplet

Three-dimensional interactions between an advecting vortex tube and a vaporizing droplet, described by the Navier-Stokes, energy, and species equations, cause fluctuations in the droplet heating and vaporization, manifested by temporal and time-averaged variations in the droplet Nusselt and Sherwood numbers. Stefan flux not only inhibits the droplet heating, it also 'blocks' the influence of vortex collision on the droplet interface inhibiting Nusselt number perturbations. The Stefan flux has a primary effect on the Nusselt number and a secondary one on the Sherwood number. Fluctuations in Sherwood number can be significant in magnitude and exhibit self-similarity in both the temporal and time-averaged response. Derived correlations are demonstrated to be valid for at least three common fuel droplets (n-heptane, n-octane, n-decane). Furthermore, they quantify the effect of vortex collision on the droplet vaporization and compliment the accepted correlations for droplets in axisymmetric hows. It follows that, in spray combustion systems, vortical structures could significantly affect transport mechanisms, vaporization rates, and local mixture ratios. (C) 2000 Elsevier Science Ltd. All rights reserved.