Analysis of Gas Turbine Combustor Exhaust Emissions: Effects of Transient Inlet Air Pressure

Gas turbine combustors are often subjected to combustion instabilities because of variability of operating conditions, affecting components, and altering exhaust emissions. Herein, the analysis focuses on simulating numerically the non-premixed combustion as unsteady flamelet combustion and detailed kinetic mechanism. The goal is analyzing exhaust gases under unsteady inlet airflow conditions to define operation guidelines. The numerical approach is validated using data from the literature for nonperturbed cases. Three periodical perturbations of different amplitude show differences with the nonperturbed case. Besides emission of exhaust gases, the temperature field is sensitive to airflow inlet conditions. According to the simulation results, a strong dependence of temperature and pressure in primary and dilution zones of combustor exists on the inlet air pressure condition. Emissions of flue gases like CO and NOx respond to combustor thermal behavior showing high sensitivity to inlet air pressure as well. Results indicate that moderate pressure oscillations may derive into flashback effects. Air inlet pressure perturbations affect combustion in gas turbine can combustor. Numerical simulations show modified exhaust gases, temperature, and turbulence at outlet. Effects lead to increase-reduce the emissions of CO2, CO, and NOx. The results may help to define operation guidelines toward enhanced designs to reduce emissions. Temperature fields for perturbed and under perturbed pressure change drastically.image (c) 2023 WILEY-VCH GmbH

Automated summary

Gas turbine combustors are prone to combustion instabilities due to changes in operating conditions and components, which can affect exhaust emissions. This study focuses on numerically simulating non-premixed combustion to analyze exhaust gases and temperature fields under unsteady inlet airflow conditions. The results show that the temperature and pressure in the combustor are highly sensitive to the inlet air pressure condition, and emissions of flue gases like CO and NOx are also affected. The study suggests that pressure oscillations can lead to flashback effects and impact the combustion and emissions in gas turbine combustors.