The Prediction of Off-Design Characteristics of Axial and Axial/Centrifugal Compressors

A COMPUTERIZED METHOD is described for constrtucting loss models for axial compressor blade rows, both as a function of inlet gas direction and Mach number, with gas-path and cascade geometry required as input.

A mean line off-design prediction of the compressor characteristics is obtained by stacking the stage characteristics derived from these loss models. By calibrating the computer program calculations against measured test results a high degree of success in predicting the performance of modified and/or new designs has been achieved. Predictions covering the complete operating range from ground idle to maximum cruise conditions are possible for up to 16 stages, including the effects of variable stators and interstage bleed.