Siemens Westinghouse Power Corporation

Westinghouse Electric Corporation

Mitchell O Stokes

David J Amos

William Richard Ryan

David T Foss

Mehran Sharifi

A gas turbine combustor is provided having a nozzle housing adjacent to a main combustion zone, a diffusion fuel pilot nozzle, at least one main nozzle extending through the nozzle housing and attached thereto, and a parabolic pilot cone projecting from the vicinity of an injection port of the pilot nozzle. The parabolic pilot cone has a diverged end adjacent to the main combustion zone, and a parabolic profile forming a pilot flame zone adjacent to the injection port and the diverged end. The increased volume of the pilot flame zone provide a more stable pilot flame. The more stable pilot flame and leaner fuel/air mixture reduce NO.sub.x /CO emissions. A second gas turbine combustor is provided having a fluted pilot cone. The fluted pilot cone has an undulated diverged end adjacent to the main combustion zone forming a pilot flame zone adjacent to the injection port and the undulated diverged end. The undulated diverged end of the fluted pilot cone creates turbulence in the main combustion zone. The turbulence results in greater interaction between main and pilot combustion zones, consequently reducing NO.sub.x /CO emissions.

Pilot cones for dry low-NO.sub.x combustors

An annular premix section that reduces NO.sub.x and CO emissions of a gas turbine combustor by providing a more homogeneous fuel/air mixture for main stage combustion is provided. A gas turbine combustor according to the present invention includes a nozzle housing, a main fuel nozzle, and a main fuel swirler. A main combustion zone is located adjacent to the nozzle housing. The main fuel nozzle extends through the nozzle housing and is attached to a nozzle housing base. The tip of the main fuel nozzle is located downstream of the nozzle housing base. The main fuel swirler surrounds a portion of the main fuel nozzle, with a downstream end of the main fuel swirler located downstream of a main fuel injection port and upstream of the main fuel nozzle tip. The main fuel swirler is adapted to receive a flow of compressed air and to mix a fuel with the flow of compressed air to form a fuel/air mixture flow. An annular premix section, adjacent to the downstream end of the main fuel swirler, is adapted to receive and expand the fuel/air mixture flow. A contraction zone is located downstream of the premix section and upstream of the main combustion zone. The contraction zone is adapted to increase the velocity of the fuel/air mixture flow into the main combustion zone.

Annular premix section for dry low-NO.sub.x combustors

A main stage fuel mixer that reduces NO.sub.x and CO emissions of a gas turbine combustor by providing a more homogeneous fuel/air mixture for main stage combustion is provided. A gas turbine combustor according to the present invention includes a nozzle housing having a nozzle housing base, a plurality of main nozzles, and a main stage fuel mixer. A main combustion zone is located adjacent to the nozzle housing. Each main nozzle extends through the nozzle housing and is attached to the nozzle housing base. The main stage fuel mixer has a plurality of inlets, each of which is adapted to receive a flow of gas, and an outlet adjacent to the main combustion zone. The main stage fuel mixer has a plurality of transition ducts, each associated with one inlet. Each transition duct provides fluid communication from the inlet associated with the transition duct to the outlet.

Main stage fuel mixer with premixing transition for dry low No.sub.x

A fuel mixer for a gas turbine combustor is provided. The fuel mixer has a substantially cylindrical body with a flared end and a tapered end. The flared end is adapted for receiving compressed air and for channeling the compressed air into the fuel mixer. The fuel mixer has a fuel/air mixing disk disposed within the body proximate the flared end. A disk axis of the fuel/air mixing disk is substantially parallel to the axis of the fuel mixer body. The fuel/air mixing disk has a plurality of holes parallel to the disk axis. The fuel/air mixer reduces NO.sub.x and CO emissions in a gas turbine combustor by providing more evenly distributed fuel/air mixtures without increasing the risk of flame holding or flashback.

Fuel/air mixing disks for dry low-NO.sub.x combustors

A combustor for a gas turbine having primary and secondary combustion zones. The combustor has primary gas fuel spray pegs for supplying a lean mixture of gaseous fuel to the primary combustion zone via a first annular pre-mixing passage and secondary fuel spray bars for supplying a lean mixture of fuel to the secondary combustion zone via a second annular pre-mixing passage. The fuel spray bars are aerodynamically shaped and a row of fuel discharge ports are formed on opposing sides of the spray bar. A pair of mixing fins project outwardly from the spray bar sides. The fins create turbulence in the air flow that ensures adequate mixing of the fuel and air. The fins have sufficient height and are displaced sufficiently far from the fuel discharge ports so that although the turbulence has not dissipated by the time the air flow reaches the fuel discharge ports, the zone of recirculation located downstream from the fins does not extend to the fuel discharge ports. This ensures that the spray bars will not act as flame holders and cause combustion to occur prematurely within the pre-mixing passage.

Growing community of inventors

Orlando, FL, United States of America

Mitchell O Stokes