Coupled study of the film and spray on a basic annular prefilming airblast atomizer
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.
Electropneumatic actuators are more and more used in industrial applications. Due to nonlinear phenomena, for many applications, high accuracy can only be obtained when using nonlinear control laws. These strategies allow to get high performances but often need the knowledge of all state variables. Then, there is a real interest to design observers in order to estimate state from the measurements of only one of the chamber pressures in the actuator and carriage position. This paper focuses on a comparison between two nonlinear observers for a half-meter stroke electropneumatic unsymmetrical cylinder controlled by two three-way servodistributors: a high gain observer and a sliding mode one. Simulations are made with a fluid power systems dedicated software, AMESim.