Numerical investigation of the local and global supersonic combustion characteristics of ethylene fuel

Abstract

In supersonic combustors, cavities play an active role in the process of fuel injection and flameholding. This study numerically investigates the influence of chemical kinetics on the local and global heat release predictions of supersonic combustion of ethylene. To this end, three-dimensional compressible, turbulent, Favre-averaged Navier-Strokes reacting-flow calculations have been carried out with a single-step chemistry model and a multi-step chemistry model. The reacting flow calculations have been performed with and without the presence of an inclined cavity in a model supersonic combustor. The heat release patterns obtained using the single-step and multi-step chemistry are compared. Furthermore, the heat release patterns are correlated with the variation of reaction rates involved in different chemistry models. In addition, the overall performance metrics such as mixing efficiency and combustion efficiency are used to draw inferences on the nature (whether mixing- or kinetic-controlled) and the completeness of the combustion process. The predicted values of the dimensionless wall static pressure are compared with experimental data reported in the literature. The calculations show that not only the multi-step chemistry model predicts the heat release better than single step chemistry, but also, the intricate details of the combustion process inside the combustor configurations.