One-Dimensional Analysis of Double Annular Combustor for Reducing Harmful Emissions

The number of aircraft flights worldwide has increased steadily since the introduction of air transportation to the public. Accordingly, environmental issues caused by the exhaust gases of aircraft engines have emerged. In particular, international organizations have crafted emission regulations since gases exhausted during takeoff and landing have been identified as the direct cause of air pollution near airports. Nitrogen oxides (NOx) produced at high combustion temperatures and carbon monoxide (CO) due to incomplete combustion affect the performance of the combustion chamber. Therefore, annular combustors comprising two annular zones have been developed to reduce the emissions of these two substances, which occur under different conditions. Parameters that should be considered when modifying a conventional single annular (SAC) to a double annular combustor (DAC) are discussed herein. In this paper, an optimization algorithm for obtaining the main design parameters of the DAC is presented to minimize NOx and CO emissions and an operation solution for reducing carbon monoxide emission is identified. A thermodynamic model of a high-bypass turbofan engine (PS-90A) is used to establish the inlet and outlet conditions of the combustor. Analysis results show that NOx emissions can be effectively reduced by adjusting the design parameters and CO emissions can be significantly decreased by partially turning off the fuel supply based on the engine cycle.