The LM2500+ gas turbine, rated between 39,000 to 40,200 shaft horsepower (shp), was introduced for field service in 1998. This growth aero-derivative gas turbine is suitable for a variety of power generation applications, such as co-generation and combined cycle, as well as mechanical drive applications. At the heart of the LM2500+ 25% power increase is an up-rated derivative 17-stage axial compressor. This paper describes the aerodynamic design and development of this high pressure ratio single spool compressor for the LM2500+ gas turbine. The compressor is derived by zero-staging the highly efficient and reliable LM2500 compressor to increase the flow by 23% at a pressure ratio of 23.3:1. The aerodynamic efficiency of the compressor is further improved by using three-dimensional, custom-tailored airfoil designs similar to those used in the CF6-80C2 high pressure compressor. The compressor achieved a peak polytropic efficiency above 91 percent, meeting all its operability objectives. The technical requirements and overall aerodynamic design features of the compressor are presented first. Next, the zero stage match point selection is described and the procedure used to set up the vector diagrams using a through-flow code with secondary flow and mixing is outlined. Detailed design results for the new transonic airfoils in the compressor using three-dimensional viscous analysis are presented. The compressor instrumentation and performance test results are discussed. The performance of the zero stage is separated from that of the baseline compressor with the CF6-80C2 airfoils to show the improvement in efficiency with the new airfoils.

Typically cooling air must be metered into cavities bordering turbine disks to offset cavity air temperature rise due to windage generated by air drag from rotating and stationary surfaces and the ingestion of hot mainstream gas. Being able to estimate the minimum amount of cooling air required to purge turbine rim cavities accurately is important toward providing optimum turbine cycle performance and hardware durability. Presented is an overview of a method used to model windage rise and ingestion on a macroscopic scale. Comparisons of model results to engine test data are included.

A practical system for flow measurement in rotating seals using the injection and sampling of a tracer gas is presented. Carbon dioxide or helium is injected as a tracer into a labyrinth seal at a controlled rate and gas samples are extracted downstream for concentration measurement. Test results from a rotating labyrinth seal rig were obtained over a range of seal pressure ratios and rotor speeds in order to determine the conditions which assure optimum tracer gas mixing. Seal leakage rates calculated by tracer gas concentration are compared to venturi flow measurements.

The LM2500ϩ gas turbine, rated between 39, 000-40,200 shaft horsepower (shp), was introduced for field service in 1998. This growth aero-derivative gas turbine is suitable for a variety of power generation applications, such as co-generation and combined cycle, as well as mechanical drive applications. At the heart of the LM2500ϩ 25% power increase is an up-rated derivative 17-stage axial compressor. This paper describes the aerodynamic design and development of this high-pressure ratio single-spool compressor for the LM2500ϩ gas turbine. The compressor is derived by zero-staging the highly efficient and reliable LM2500 compressor to increase the flow by 23% at a pressure ratio of 23.3:1. The aerodynamic efficiency of the compressor is further improved by using threedimensional, custom-tailored airfoil designs similar to those used in the CF6-80C2 highpressure compressor. The compressor achieved a peak polytropic efficiency above 91%, meeting all its operability objectives. The technical requirements and overall aerodynamic design features of the compressor are presented first. Next, the zero stage match point selection is described and the procedure used to set up the vector diagrams using a through-flow code with secondary flow and mixing is outlined. Detailed design results for the new transonic airfoils in the compressor using three-dimensional viscous analysis are presented. The compressor instrumentation and performance test results are discussed. The performance of the zero stage is separated from that of the baseline compressor with the CF6-80C2 airfoils to show the improvement in efficiency with the new airfoils.