Validation of a CFD Model for the Simulation of Combustion in a Bluff Body Test Case

This thesis project consists of the development of a combustion model able to replicate the functioning of a bluff body burner, characterized by a non-premixed flame and run with a mixture of CH4 and H2 (50% by volume), by means of a CFD (Computational Fluid Dynamics) software called CONVERGE. The project is a new starting point in the creation of a reliable model for a real turbine combustor and so enlarge the field of application of the abovementioned software, now mainly used for modelling internal combustion engines. The whole thesis project has been carried out at the CFD company Convergent Science GmbH in Austria and all the experimental data has been provided by the Aerospace, Mechanical and Mechatronic department of the University of Sidney, that has collected them using LDV technique. The project itself deals with the whole development and validation of the model, from the geometry to the combustion models (FGM and SAGE) and the reaction mechanisms (CRECK Mechanism), in order to fit perfectly the reactions accomplished by the oxidation of the fuel in air. The thesis can be subdivided in three main parts: the first one is a review of all the fluid dynamics governing equations, used by the software to figure out the results of each simulation, and a short description about the innovative system of automatic mesh generation typical of CONVERGE; the second part consists of the illustration and description of all the results obtained with the non-reactive flow case, i.e. the model run without combustion; the third and last part deals with the most interesting and difficult part of the project, i.e. the reacting flow, taking into account the combustion process, the temperature and velocity fields, and the analysis of the various combustion products, compared with the experimental data.