Modeling of internal two-phase flow field inside a turbojet combustion chamber application to in-flight re-light

摘要

The study presented in this paper is conducted in the frame of turbojets combustion chambers optimization by the increase of efficiency and the reduction of polluting emissions. The operating critical conditions at high altitude make it more difficult to control both the ignition and the re-light process after an accidental in-flight flameout. In this context, a numerical model has been developed to predict the behavior of a two-phase kernel when submitted to the electrical spark's discharge inside the combustor. This model is based upon the resolution of the mass species and energy conservation equations linked with the state equation of the gas; it takes account of the various physical and chemical phenomena involved, such as the fuel-drops vaporization, the chemical kinetics and the turbulent transfers. The turbulent two-phase flow field corresponding to an experimental combustion chamber of simple geometry has been computed using an Enlerian-Lagrangian approach and then the kernel's ignition model has been applied to determine numerically an optimal location for the spark-plug. This paper presents in detail the kernel's ignition model and some results of its application that are compared with experimental results.