At ONERA Fauga-Mauzac center, a new air-breathing propulsion test setup, Prométhée-LACOM, has been recently developed. In this paper, both non-reacting and reacting two-phase flows were investigated. In reacting two-phase flow, simultaneous OH-PLIF and Mie scattering imaging were implemented in order to characterize the flame structure. The different behaviours observed in this study seem to support the existence of spray combustion regimes. Moreover, statistical analysis were performed on the spatial distribution of droplets and indicated that the centre-to-centre inter-droplet distance (nearest neighbour) could be described by means of a Log-Normal distribution.