Theory of Azeotropic Gasification of Miscible Multicomponent Droplets

Abstract

Analytical studies of quasi-steady and spherically-symmetric gasification of miscible multi-component droplets in a quiescent ambient are presented. Emphasis is placed upon identifying conditions where azeotropic gasification (defined as gasification with time-invariant droplet compositions) may occur. It is shown that if differences between gas-phase species diffusivities are negligible, azeotropic gasification states correspond to thermodynamic azeotropic states. These thermodynamic azeotropic states are at the partial pressure of the droplet components in the gas phase at the liquid surface; ignoring insoluble gas-phase components, the gas and liquid compositions at the gas-liquid interface are the same. When gas-phase preferential species diffusion is significant, azeotropic gasification states are shifted away from thermodynamic azeotropic states. Theory suggests that under special circumstances, gas-phase preferential diffusion may induce azeotropic gasification or volatility reversal for droplets that do not form a ther-modynamically azeotropic mixture.

Key words:

• Azeotrope
• combustion
• droplet
• gasification
• miscible
• multicomponent.

Additional information

Notes on contributors

B. D. SHAW

Present address: Department of Mechanical, Aeronautical and Materials Engineering, Universily of California, Davis. CA 95616-5294, U.S.A.