Steam-Cooled Gas Turbine Casings, Struts, and Disks in a Reheat Gas Turbine Combined Cycle: Part II—Gas Generator Turbine and Power Turbine

Abstract

High-cycle pressure-ratio (38–42) gas turbines being developed for future aircraft and, in turn, industrial applications impose more critical disk and casing cooling and thermal-expansion problems. Additional attention, therefore, is being focused on cooling and the proper selection of materials. Associated blade-tip clearance control of the high-pressure compressor and high-temperature turbine is critical for high performance. This paper relates to the use of extracted steam from a steam turbine as a coolant in a combined cycle to enhance material selection and to control expansion in such a manner that the cooling process increases combined-cycle efficiency, gas turbine output and steam turbine output.