Experimental and Numerical Study of Spray Ignition for In-Flight Re-Light

The context of this study is the prediction of re-ignition for turbojet engines after in-flight extinction at high altitude. Experiments have been performed on a simple geometry of a combustion chamber to test ignition at ambient conditions for three positions of the spark plug. Then, the two-phase flow corresponding to the experimental configuration has been simulated with the eulerian-lagrangian code used at ONERA. In parallel, a time dependent 0-dimensional model has been developed to predict the ignition of a cluster composed of fuel droplets when it is submitted to the spark inside the combustion chamber. This model has been applied on the two-phase flow computation in three elementary volumes located close to different spark plug positions. Ignition has been tested numerically for these clusters of drops, whose characteristics are dependent of their location in the combustion chamber, as well as, of the two-phase flow configuration in the geometry. Comparisons between experimental and numerical results are presented in this paper.