An Application of 3-D Viscous Flow Analysis to the Design of a Low-Aspect-Ratio Turbine

Previously reported cascade test results verified and provided a calibration of the 3-D viscous flow analysis. This paper describes the subsequent AFAPL-sponsored technology program in which the 3-D viscous flow computer program was used to optimize the low-aspect-ratio stator of a high-work turbine stage. The optimization procedure, in conjunction with the radial distribution of energy extraction, led to innovative-but-realistic blading for advanced gas generator turbines. A turbine stage was tested with this stator, in conjunction with an appropriate rotor design. The total-to-total design-point efficiency — 92 percent at 1-percent tip clearance — was achieved at 31.83 Btu/lbm specific work. In addition to stage tests, separate stator tests were conducted including a measurement of total pressure loss and stator reaction torque, which provided baseline data to assess interaction effects during stage testing with stator reaction measurements “in vivo.”