Numerical Simulation and Experimental Investigation of Methane-Air Non-Premixed Strongly Swirling Combustion in a Novel Asymmetric Semi-Confined Combustor

Abstract

In this paper, a novel asymmetric non-premixed combustor with well-defined geometric boundary is provided to enhance air/fuel mixing and improve flame stability. A comprehensive numerical model, which coupled with large-eddy simulation using a modified Sub-grid scales kinetic energy model and second-order moment combustion model using a simplified four steps chemical reaction mechanism, for non-premixed combustion in a semi-confined space is established. The results show that four isolated vortices characterized by the features of strongly rotating and tangential shear stress are formed in the corner region of combustor. With the increases of inlet gas velocity, the flame blow off do not happen and the average temperature in the combustor remain mostly uniform low and well distributed. Combustion intensity, vortex structures forming and shedding which involves turbulent mixing, chemical reaction and flame propagation is affected by the strongly swirling flow field structure.