DISPERSION OF EVAPORATING DROPLETS IN A SWIRLING AXISYMMETRIC JET

摘要

The effects of swirl and vaporization on droplet dispersion are investigated in the near region of a two-phase, swirling, heated jet. Simulations are based on the numerical solution of time-dependent, axisymmetric gas-phased equations. Droplets' trajectories are tracked by using a Lagrangian approach. For all of the swirl cases investigated, the droplet dispersion exhibits a nonmonotonic behavior, with the maximum dispersion occurring near Stokes number (St) unity. As the swirl intensity is increased, the radial dispersion of both nonevaporating and evaporating droplets is significantly enhanced. We atribute this dispersion enhancement to two factors:1) increased vortex pairing interactions caused by swirl and 2) transfer of gas-phase swirl momentum to droplets.