18:1 pressure ratio axial/centrifugal compressor demonstration program

The results of a component technology demonstration program to design and test an advanced axial/centrifugal compressor for industrial gas turbine applications are presented. Objectives were to demonstrate 18:1 pressure ratio at 90% polytropic efficiency with 80% fewer parts as compared to current industrial gas turbine compressors. The compressor design approach utilizes low-aspect-ratio/highly loaded axial compressor blading combined with a centrifugal backend stage to achieve the 18:1 design pressure ratio on a single spool in only seven stages. Demonstrated design point performance was 91.5% polytropic efficiency at 14% stall margin and 70 Ibm/s flow. This represents the highest known demonstrated performance in this pressure ratio and flow class. The results are particularly significant in that they were accomplished at axial compressor aerodynamic loading levels approximately 15% above current production engine design practice.