CHARACTERIZING AIRFLOW IN THE ANNULAR COMBUSTOR DIFFUSER OF AN AVIATION GAS TURBINE ENGINE

Abstract

In the combustor of aviation gas turbine engines, the diffuser’s role is to reduce the airflow velocity (generated from the compressor) to restrain the pressure loss. Characterizing the airflow in the diffuser is essential for further studies on the processes occurring in the combustor such as fuel atomization, mixing, and combustion. This paper has successfully developed a 3D simulation model using Star CCM+ to characterize airflow in an annular combustor diffuser equipped in a gas turbine engine. The results obtained from this study show that this diffuser reduces airflow velocity by 65%, increases static pressure by 2%, whereas the total pressure slightly reduces (the maximal reduction is 0.8% in the emergency regime) in comparison with the conditions at the compressor outlet. The amount of air directly supplying into the burner attains about 20%, in which the amount of air passing through the swirler makes up 9% of the total amount under the nominal regime.