A method to extend flamelet manifolds for prediction of NOx and long time scale species with tabulated chemistry

摘要

Numerical simulation is currently used to help design low NOx devices for aircraft engines. In order to improve the prediction of pollutant species, combustion models based on tabulated chemistry have been commonly used in recent years. However, the short time scales of usual flamelet manifolds can lead to errors concerning the NO prediction in post flame area, as shown in this paper. Thus, a new method is proposed to extend the manifold in order to describe the evolution of species with a long characteristic time. This method is tested in the framework of 0D-1D computations. The use of the extended manifold is shown to be necessary to correctly predict the evolution of NO concentration in burnt gases. As an example, the extended and classical manifolds were compared in the framework of 2D simulations of an industrial-like combustor, showing an evident difference on the NO levels predicted in the outlet section.