EXTERNAL CLUSTER COMBUSTION OF BINARY-FUEL DROPS

A model describing external sheet combustion of a cluster of drops has been developed for clusters of binary-fuel drops. The binary-fuel is assumed to be a solvent-solute combination in which the solute is much more volatile than the solvent whose initial mass fraction within the mixture is larger than that of the solute. Both the ignition timing a nd location are calculated using criteria previously derived; for the range of air/fuel mass ratios considered, ignition always occurs aroun d the cluster. Following ignition, an internal dash dame burns all the oxygen within the cluster. An external sheet dame ensues fueled by va por released from the cluster. Results show that drop interactions are important in modifying the amount of fuel burnt. It is only for small initial cluster velocities and for large air/fuel mass ratios that th e external flame behaves approximately like a classical diffusion dame in that it almost burns all the fuel released from the cluster. For a ll other conditions, the amount of fuel burnt is smaller than that rel eased from the cluster. These conclusions are independent of the initi al solute mass fraction and of the Arrhenius ignition parameters havin g assumed them identical for solvent and solute.