Effect of injection angle of primary and secondary holes on the mixing and combustion in a can type combustor using CFD

Abstract

Combustion is one of the vital process in power generation system and so is the combustor in a Gas Turbine. The performance of combustor has greater impact on the efficiency of the cycle, as a result combustor has always been on the prime focus for researchers to improve the efficiency of gas turbine. The present study is focused on numerical analysis, using ANSYS FLUENT, of combustion performance using slotted swirler with swirl angle of 45°. In this study, considering the importance of primary and dilution injection on combustion performance, the injection angle is varied 60° to − 60° from normal to the liner wall. Furthermore, the curvature of primary and dilution hole is formed in the form of nozzle and diffuser having convergence and divergence angle of 30° and 45°. Because of high swirling effect (S = 1.32), RSM (7 equations) turbulence model is used along with Non-Premixed combustion mechanism by generating β-PDF table. The performance is determined by the mass fraction of CO2 at outlet. Higher the mass fraction of CO2 at outlet, signifies better combustion. From the study it is reflected that the slotted swirler have better combustion performance than non-slotted swirler whereas variation of injection angle suggests, injection at 30° clockwise is more suitable. Also, primary injection done through nozzle channel (convergence angle of 45°) and dilution injection through diffuser channel (divergence angle of 45°) results in most efficient combustion performance.