One way to increase efficiency and reduce pollution in transport and energetic domain is designing fuel injectors with better atomization. In this work, experiments were performed on a prefilming airblast atomizer often used in gas turbine engines. For this purpose, a new injector was designed to visualize the prefilming zone and the primary atomization together. The flow configuration corresponds to an annular liquid film sheared by inner high velocity airflows. High speed Shadowgraphy was used to observe film and spray, liquid film frequency, wave velocity and wave deformation, primary breakup regime. Finally, a link between liquid film and the primary atomization are shown first qualitatively and after quantitatively. KeywordsAtomization, liquid film, annular geometry, airblast, prefilming IntroductionOne way to increase efficiency and reduce pollution in transport and energetic domains is designing fuel injectors with better atomization properties [1]. Prefilming airblast atomizers often used in gas turbine engines, offer advantages in terms of atomization quality over a wide range of fuel flow rates. Nevertheless, spray formation mechanisms due to the disintegration of a liquid film are still not completely known. This type of injector is often studied in a planar geometry separately. In this context, we propose an experimental study on the liquid film and the spray for a basic annular prefilming airblast. The paper starts by presenting the experimental set-up designed at IMFT (Institut de Mécanique des Fluides de Toulouse). The destabilization and the atomization of the liquid film have been studied with high speed shadowgraphy method. Then the liquid film is characterized with its different regimes, frequencies of waves, wave velocities and wave deformations. Furthermore observations are made on the regimes of sprays, the possible dependence between the liquid regime and breakup modes. And to finish the preservation between conditions of film near the injector exit and the initial conditions about the primary atomization.