In this lesson we will cover the LM2500 design and operating characteristics, and discuss how these features affect overall operation of a gas turbine platform. Today's operational gas turbine engines use the open Brayton cycle. . Atmospheric air provides the working mass. . The mass is drawn from the atmosphere and compressed. . Heat is added by mixing fuel with the compressed air and igniting the mixture. .
Work is extracted by expanding the hot gases through a turbine. .
In the combustor section, fuel is added through fuel nozzles and combustion occurs. . A two stage high pressure turbine on the exhaust end of the combustor drives the compressor. . The combination of the compressor, combustor, and high pressure turbine are often called the gas generator. . The exhaust from the high pressure turbine passes through a low pressure turbine which extracts the work required to drive the main reduction gear and ultimately the ship's propeller. . The IGVs and the first six stages of stator vanes are variable in that they pivot on their mounting points to control the amount of air flowing through the compressor. .