Research on the Influence of Low NO_x Combustor on Combustion Pressure Oscillation in 9E Gas Turbine

9E gas turbine mainly operates in three combustion modes: primary mode, lean-lean mode and premixed mode. Portable equipment was used to monitor the combustion status and obtain the combustion pressure oscillation data under the whole working condition. Study on the patterns of combustion status was conducted by combining this data with the operational parameters and emission indicators of gas turbine. Results show that there are four abrupt change points in pressure oscillation during the process from startup to full load, corresponding respectively to the ignition moment, the grid connection moment, the moment when the combustion temperature reference reaches 898.9 ℃, and the moment when it reaches 1 077.2 ℃. The peak value of the gas turbine combustion pressure oscillation shifts as the load increases. In primary mode, the combustion pressure oscillations are dominated by lean blow out and cold tone; in lean-lean mode, they are dominated by hot tone. As the gas turbine gradually enters the stable premixed mode, hot tone decreases slightly, while cold tone increases. When the inlet air temperature rises: in primary mode, lean blow out increases significantly, cold tone decreases slightly, and hot tone shows no significant change;in lean-lean mode, hot tone decreases significantly, while cold tone and lean blow out increase; in premixed mode, hot tone increases slightly, cold tone decreases slightly, and lean blow out decreases significantly.