Theoretical and experimental advances on the transient, convective, multicomponent droplet vaporization are reviewed, with particular emphasis on the internal heat, mass, and momentum transport processes and their effects on the bulk vaporization characteristics. Whereas these processes have only small quantitative effects on single--component droplet vaporization, they can modify qualitatively the vaporization behavior of a multicompoent droplet. Depending on the intensity of convective transport through internal circulation, liquid-phase mass diffusion or the volatility differentials among the various components can become the rate-limiting factor. The generation of internal circulation through the surface shear induced by external gas streams is discussed. Some potentially interesting and practically important research problems are identified.
Tn many chemical power plants the fuel is introduced inthe form of a spray. The droplets subsequently vaporize as they are dispersed in the reactor. Frequently chemical reactions are initiated prior to the complete vaporization of the droplets, and the flame will then propagate through a mixture consisting of fuel vapor, fuel droplets, and other gaseous components, including the oxidizer. Both direct and indirect studies on the performance of various types of engines indicate that the resulting combustion characteristics depend significantly on the amount and the sizes of the fuel droplets that are present when active chemical reactions are initiated. Hence studies on spray vaporization and combustion are of 0-8412-0383-0/78/33-166-003$06.50/0