In this paper, we present the time-dependent axisymmetric numerical simulation of a n-heptane evaporating spray, and investigate the droplet-vortex interactions which determine the structural and dynamic characteristics of a spray jet flow. The spray is formed between a droplet-laden healed nitrogen jet and a coflowing air stream. A detailed, multidimensional, two-phase algorithm is developed for the simulation. Monodisperse spray is introduced into the large vortex structures that are generated by the buoyancy-induced hydrodynamic instability of the heated jet. Results focus on the two-way interactions between vortical structures and droplets, and the dynamics of both non-evaporating and evaporating sprays. The vortex structures cause droplets to disperse radially outward, and this in turn determines the fuel vapor distribution and also modifies the vortex dynamics. Thus, the dynamics and structural characteristics of evaporating sprays are strongly influenced by the two-way transient interactions. The effects of initial droplet size, injection location, and liquid-to-gas mass loading ratio on these interactions are investigated. These studies indicate that the effect of dispersed phase on gas phase is negligible for mass loading ratio less than 0.5. At higher mass loading ratios, the dispersed phase modifies the dynamics of vortex structures but not the time-average behavior for non-evaporating spray, while for evaporating spray it influences both the dynamics and the time-averaged behavior. It is also found that the spray injection characteristics have strong influence on the processes of droplet-vortex interactions.