General Electric Company

Anil Gulati

Eayre Bruce Voorhees

Elwin C Bigelow

Anthony John Dean

Masayoshi Kuwata

Thomas Frank Fric

Jeffery Allan Lovett

David Graham Holmes

Richard Edwin Warren, Jr

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.

Combustors with improved dynamics

Combustion-induced instabilities are minimized in gas turbine combustors by incorporating one or more Helmholtz resonators into the combustor. First and second plates located in the head end of the combustor casing define one cavity, and a sleeve located between the casing and the liner defines another cavity. Each of the two cavities is connected to the combustion chamber by one or more throats, thus forming Helmholtz resonators. The throats of each resonator can be tubes of different lengths and/or different cross-sectional areas to provide dynamics suppression over a broad band of frequencies. The throats can also be arranged such that each throat is associated with a different portion of its respective cavity, each cavity portion having a different volume.

Dynamics free low emissions gas turbine combustor

Combustion-induced unsteady oscillations referred to as screech are suppressed in gas turbine combustors by a plurality (preferably two to six) of screech suppression members disposed in the premixers of the combustors. The screech suppression members are attached to the centerbody of the premixer and extend radially outward, nearly into contact with the inner surface of the premixer tube. The screech suppression members are uniformly spaced about the centerbody and are axially positioned at or near the end of the centerbody which is closest to the main combustion chamber. Alternatively, each screech suppression member can be attached to the inner surface of the premixer tube and extend radially inward nearly into contact with the centerbody. Possible shapes of the screech suppression members include a thick block, a thin rectangular plate, a triangular plate, a V-shaped member, and a cylindrical bar.

Screech suppressor for advanced low emissions gas turbine combustor

Lean direct injection is used in a gas turbine combustor to reduce NO.sub.x emissions. The combustor has a plurality of fuel jets for tangentially injecting fuel and a plurality of air jets for tangentially injecting air therein. The fuel jets and the air jets are preferably disposed in a common cross-sectional plane, although additional groups of fuel and air jets in other planes can be provided. The jets are all evenly spaced and alternate between fuel and air jets. All of the jets preferably point in the same circumferential direction. Alternatively, the jets can be arranged so that all fuel jets are located in a first cross-sectional plane, and all air jets are located in a second cross-sectional plane. Preferably, the fuel jets point in one circumferential direction while the air jets point in the opposite circumferential direction.

Low emission combustor having tangential lean direct injection

A V-shaped afterburner flameholder for a gas turbine engine has a plurality of rectangular tabs coextensive with and lying in the planes of the flameholder sidewalls. The tabs on opposing sidewalls alternate so as to introduce streamwise and spanwise (transverse) vortices in the flowing gas. The resultant streamwise vortices tend to reduce resonating vortex oscillations (screech) and the need for an acoustic liner to suppress such screech.

Flameholder for gas turbine engine afterburner

An afterburner flameholder for a gas turbine engine having a central diffuser cone, a generally cylindrical outer shell and fuel spray bars between the shell and cone defining an afterburner region is provided, which comprise an annular member with an asymmetric V-shaped cross section. The annular member is adapted to be secured to the engine in the afterburner region with the apex of the V facing upstream in the axial direction toward the fuel spray bars. The annular member has a first and second circular sidewall member each joined at one end forming an apex, the annular member in cross section has unequal length sidewall members. The difference in length between the distal ends of the first and second circular sidewall members is sufficient to cause spanwise vortices shed at the distal ends of the sidewall members to be out of phase when they meet downstream from the flameholder. The different lengths of the distal ends of the sidewall members results in one sidewall member extending further from the apex than the other, situating the distal ends in different planes so that spanwise vortices shed from the asymmetric sidewall members travel different path lengths and are out of phase when they meet downstream.

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Albany, NY, United States of America

Anil Gulati