COUPLED EVAPORATION AND TRANSPORT EFFECTS IN COUNTERFLOW SPRAY DIFFUSION FLAMES

A new theoretical study of counterflow spray diffusion flames is prese nted. The fuel is introduced into the system in the form of liquid dro plets suspended homogeneously in an inert environment. Analytic soluti ons are developed for the entire range of injection velocities, includ ing large rates of injection for which asymptotic expansions based on the reciprocal of the injection velocity are involved. The sensitivity of flame position and temperature to combined transport, vaporization and liquid fuel spray-related and injection rate effects is analyzed in a comprehensive study of calculated results. These results were obt ained assuming an infinite chemical Damkohler number so that the flame appears as a thin front. Additional numerically computed results with finite rate chemical kinetics show that the presence of the spray of vaporizing droplets tends to make flame extinguishment easier and igni tion more difficult than in the single gas-phase counterflow diffusion flame situation.