Autoignition of sprays in a cylindrical combustor

In this work, the physical characteristics of autoignition phenomena of liquid fuel sprays injected into hot and stagnant air, has been investigated. Eulerian (gas)/Lagrangian (droplets) formulations were adopted to analyze the two-phase flow in a confined 2D axisymmetric cylindrical combustor. The unsteady governing equations were solved considering two-phase interactions together with the particle source in cell (PSI-cell) model, which accounts for the finite rates of transports between phases. Instead, an infinite conduction model was adopted for the vaporization of droplets. The results have shown that the process of the autoignition is governed by droplet heating, vaporization, mixing and chemical reaction. The onset of ignition was determined by an incipience of the rapid increase in the maximum reaction rate. The effect of initial gas temperature on ignition delay time was found to be dominant, followed by the initial droplet size. However, it was also found that the injection angle as well as the injection velocity plays some role in affecting the ignition delays.