Experiments on a Low-Emission Two-Stage Model Combustor for a Medium-Power Gas Turbine

This paper is the last in the series on the reasearch into the sequential combustion process in a combustor with an outlet gas temperature of 1600 – 1700°C and permissible levels of CO and NOx emissions. The results of experiments on a model sequential combustor with an outlet gas temperature of 1460°C at a rated load are presented. The possibility of increasing the temperature to 1690°C was examined. The goal was to confirm that the combustor can operate in the range from 700 to 1700°C. The combustor has two sequential burners. The values of the velocities and air and fuel flow rates in both stages are taken from the previous studies. The model combustor was tested in the following operating conditions of the gas turbine: idling, transition to low-emission operation, and full load. The emission characteristics are compared for the following three schemes of combustion: (i) the air and fuel are supplied only to the first burner, the second burner being closed; (ii) the air is supplied to both burners while the fuel is supplied only to the first burner, the second burner operating as a combustor mixer; (iii) the air and fuel in optimal ratio are supplied to both burners.