Air fuel mixer for gas turbine combustor

摘要

An apparatus for premixing fuel and air prior to combustion in a gas turbine engine, including: a linear mixing duct having a circular cross-section defined by a wall; a centerbody located along a central axis of the mixing duct and extending substantially the full length of the mixing duct, the centerbody having a plurality of orifices therein to inject fuel into the mixing duct with an axial velocity component; a fuel supply in flow communication with the centerbody orifices; an outer annular swirler located adjacent an upstream end of the mixing duct and including a plurality of circumferentially spaced vanes oriented so as to swirl air flowing therethrough in a first direction; an inner annular swirler located adjacent the mixing duct upstream end and including a plurality of circumferentially spaced vanes, the vanes having an outer radial portion having a leading edge and a trailing edge oriented so as to swirl air flowing therethrough in a second direction opposite the first swirl direction by the outer annular swirler vanes and an inner radial portion with a leading edge and a trailing edge oriented so as to provide a boundary layer of air substantially along the centerbody; and, a hub separating the inner and outer annular swirlers to permit independent rotation of an air stream therethrough. The outer annular swirler may also include vanes having an inner radial portion with a leading edge and a trailing edge oriented so as to swirl the air flow therethrough and an outer radial portion having a leading edge and a trailing edge oriented so as to provide a boundary layer of air substantially along the mixing duct wall. High pressure air is injected from a compressor into the mixing duct through the inner and outer annular swirlers and fuel is injected into the mixing duct so that the high pressure air and the fuel is uniformly mixed therein, whereby minimal formation of pollutants is produced when the fuel/air mixture is exhausted out the downstream end of the mixing duct into a combustor and ignited.