Combustors with improved dynamics

摘要

A combustor comprises an outer combustor casing defining a plurality of circumferentially adjoining combustion chambers. Each combustion chamber comprises a dome at an upstream end and an outlet at a downstream end. A plurality of pre-mixers are joined to the combustor dome of each respective combustion chamber. The pre-mixers comprise a duct having an inlet at one end for receiving compressed air, an outlet at an opposite end disposed in flow communication with the combustion chamber and a swirler disposed in the duct adjacent the duct inlet for swirling air channeled therethrough. A fuel injector is provided for injecting fuel into the pre-mixer ducts and for mixing with the air in the ducts for flow into the combustion chamber to generate a combustion flame at the duct outlets. A portion of the pre-mixers comprise an altered flameholding capability so as to distribute the resulting combustion flames from the respective portion of the pre-mixers axially downstream with respect to the non-altered pre-mixers so as to reduce the dynamic pressure amplitude of the combustion flames.