TRANSIENT DEFORMATION AND EVAPORATION OF DROPLETS AT INTERMEDIATE REYNOLDS-NUMBERS

The early life histories of isolated n-heptane droplets injected into 1000 K air at 1 and 10 atm with initial Reynolds and Weber numbers of 100 and 2, respectively, are reported. A numerical model is used to pr edict the transient droplet shape, and the velocity, pressure, tempera ture and concentration fields in both phases. Initially spherical drop lets show strongly damped oscillations at frequencies within 25% of th e theoretical natural frequency of Lamb (1932). Circulation within the droplets is responsible for the observed strong damping and promotes the formation of prolate shapes for surfactant-free droplets. The comp uted heat and mass transfer rates are well predicted by existing quasi -steady correlations.