Two-phase flow measurements in coaxial jets (water and tenside aqueous solutions - air) with similar velocities and injector geometry to the VULCAIN engine were the main purposes of this study. Firstly, a fiber optic device determined the Liquid Presence Probability (LPP = 1 - void fraction) in the dense part of the jet. Secondly, the Phase Doppler Particle Analizer (PDPA) technique measured diameters and velocities of liquid particles. The following results were obtained . i) radial and axial Liquid Presence Probability distributions present a characteristic behaviour of the dense phase in the near field, more evident for initial liquid velocity ≥ 15 m.s-1, ii) the dilute spray region (LPP ≤ 0.1) exhibits phase slipping and contains little volume of the injected liquid.