Evaporation of liquid droplets containing small solid particles

Abstract

Evaporation of a liquid droplet containing small solid particles (slurry droplets) is analyzed in a quasi-steady approximation. The developed model takes into account effects of compressibility and filtration of a gas-vapor mixture within the porous shell. It is shown that in the case of small temperature differences in the neighborhood of a slurry droplet at the second stage of drying (evaporation through a porous shell), the regime of slow evaporation and saturation (negligibly small drying rate) occurs. In the case of high temperature differences in the neighborhood of a slurry droplet at the second stage of drying, the pressure of the gas-vapor mixture within the porous shell significantly increases leading to the fragmentation of a porous shell. The comparison of the proposed model with the diffusion model, which neglects the Stefan's flux shows that the diffusion model incorrectly describes evaporation of a slurry droplet at the final stage of drying.