FUEL LANCE COOLING FOR A GAS TURBINE WITH SEQUENTIAL COMBUSTION

摘要

A fuel lance is disclosed for injecting a gaseous and/or liquid fuel mixed with air into an axial hot gas flow flowing through a sequential combustor of a gas turbine, the fuel lance having at least one finger extending in a longitudinal direction into the axial hot gas flow of the gas turbine essentially perpendicular to the hot gas flow. The finger is configured as a streamlined body which has a streamlined cross-sectional profile. The body has two lateral surfaces essentially parallel to the axial hot gas flow. The body includes an enclosing outer wall having a longitudinally extending air plenum for the distributed introduction of air into the at least one finger. The air plenum is provided with a plurality of distributed impingement cooling holes, such that air exiting through the impingement cooling holes impinges on the inner side of the leading edge region of the body.

主权项

1. Fuel lance for injecting a gaseous and/or liquid fuel mixed with air into an axial hot gas flow flowing through a sequential combustor of a gas turbine, said fuel lance comprising:
at least one finger configured for extending in a longitudinal direction into said axial hot gas flow of a gas turbine essentially perpendicular to said hot gas flow; wherein said at least one finger is configured as a streamlined body which has a streamlined cross-sectional profile; wherein said body has two lateral surfaces arranged to be essentially parallel to said axial hot gas flow, joined at their upstream side by a leading edge and joined at their downstream side forming a trailing edge; wherein a plurality of nozzles for injecting a gaseous and/or liquid fuel mixed with air are distributed along said trailing edge; wherein means for impacting the mixing quality and reducing pressure loss in said sequential combustor are provided in the trailing edge region of said body; wherein said body includes an enclosing outer wall defining said streamlined cross-sectional profile, wherein within said outer wall there is provided a longitudinally extending air plenum for the distributed introduction of air into said at least one finger, said air plenum having a distance from said outer wall, defining a first interspace; and wherein said air plenum is provided with a plurality of distributed impingement cooling holes, such that air exiting through said impingement cooling holes impinges on the inner side of the leading edge region of said body; wherein said impingement cooling holes each have a hole diameter between 1.2 and 1.8 mm; and said impingement cooling holes are arranged at said air plenum with a pitch ratio, of the distance between said holes and the hole diameter, of between 3 and 10.