A preferential vaporization model for multicomponent droplets and sprays

A multicomponent vaporization model for spray computations was developed to account for the temperature and concentration nonuniformity inside a droplet due to preferential vaporization and finite diffusion processes. The effect of internal circulation was also included using effective diffusivity. The model was validated through rigorous tests and the results agreed well with accurate finite-difference solutions for temperature temporal variations of nonvaporizing droplets and with the measured mole fraction temporal variations of bi-component droplets. The model was also applied to investigate the vaporization of solid-cone sprays and physical insights on preferential vaporization were revealed. Throughout the tests, comparisons with the widely used infinite diffusion model (limited accuracy, low computational cost) and the simplified vortex model (high accuracy, high cost) were also made. Overall, the accuracy of the present model is close to that of the simplified vortex model, while the computational cost is comparable to that of the infinite diffusion model.