A LES-LEM Study of Preferential Diffusion Processes in a Partially Premixed Swirling Combustor With Synthesis Gases

A lean partially premixed swirling combustor with synthesis gases is studied using large-eddy simulation (LES). The simulation used the linear-eddy mixing (LEM) model to close the unclosed subgrid scalar flux. Several terms resulting from the LES filter are not modelled but directly resolved considering their unique length and time scales, such as the molecular diffusion, scalar mixing and chemical reaction processes. The validation results show that the code and the chemical mechanism used in the present work do have reliable accuracy. With this model, the effects of preferential diffusion process on lean partially premixed swirling combustion are investigated and the results show that the characteristics of flow and combustion dynamics can be profoundly affected. The obtained results are expected to provide helpful information for the design and operation of syngas gas turbine combustor systems.