Two-phase fuel droplet burning in weightlessness

Using multicomponent and multi-phase fuels is one of the methods for increasing effectiveness of rocket engines. In developing different compositions one should guarantee a stable fuel burning process in weightlessness. The present study is aimed at developing physical and mathematical models, allowing to consider the effect of multiphase fuel (hydrocarbon liquid + solid combustible material) on the conditions of ignition and modes of propagation of combustion in poly-dispersed non-uniform mixtures. In this case, the combustion of different droplet fractions occurs in different modes: the volatile fraction evaporates and burns in the gas-phase mode, and the solid fuel fraction reacts with the oxidizer in the heterogeneous mode. The effect of the presence of a solid fraction in droplets reacting in a heterogeneous regime on the evaporation rate of the volatile fuel component is studied. The effect of tightness due to the presence of other drops on the evaporation rate of each drop is taken into account. The results of computational modeling of flame propagation during ignition of poly-dispersed mixture of liquid hydrocarbon fuel droplets with solid fine carbon particles are presented. •The mathematical model for two-phase droplet burning is developed.•The effect of multi-phase fuel (hydrocarbon liquid + solid combustible material) on droplet combustion is studied.•In the presence of condensed fuel in the droplet, the evaporation of the liquid is faster.•Increase of average density of dispersed mixture brings to the growth of flame propagation velocity.•Characteristic time for dispersed mixture burning out non-monotonously depends on initial density.