Development and Validation of a Combustion Model for a Fuel Cell

A low-emissions power generator comprising a solid oxide fuel cell coupled to a gas turbine has been developed by Rolls-Royce Fuel Cell Systems. As part of the cycle, a fraction of the unreacted fuel (the off-gas) and oxidizer streams is reacted in a burner, which is the main source of pollutant formation. In this thesis a computational model of the burner has been developed which captures the formation of NOx and the oxidation of CO. This model gives accurate predictions at low computational cost, making it suitable for use as a design tool in future burner design optimization through parametric studies. A key factor in increasing computational efciency was the development of a reduced H2/CO/N2 kinetic mechanism; from a starting mechanism of 30 species to 10 and 116 reactions to 6. The results of laminar opposed-ow diffusion ames have been used to validate the reduced mechanism. Several different turbulent combustion models have been evaluated by creating an interface between the reduced kinetic mechanism and the commercial CFD solver FLU-ENT. Comparison of model predictions with well-characterized turbulent syngas ames