An Investigation of Distortion Indices for Prediction of Stalling Behavior in Aircraft Gas Turbine Engines

TR Number



Journal Title

Journal ISSN

Volume Title


Virginia Polytechnic Institute and State University


The ability of twelve distortion indices to predict stalling behavior in aircraft gas turbine engines was investigated using J85-GE-13 turbojet engine data, TF30-P-3 turbofan engine data, and modified T64-GE-6B compressor test-rig data. The indices were tested for correlation capability with constant speed loss in stall pressure ratio, constant mass loss in stall pressure ratio, and engine speed where appropriate. Predictive indices/models were compared directly with experimental data. In addition, the concept of including the effects of compressor dynamic response by modifying the inlet total pressure profile rather than the index was investigated. This was done by evaluating the accuracy of parallel compressor theory and two simple AP/P indices first using measured inlet total pressure data and then using modified or "effective" inlet total pressure profiles. A procedure was developed for deriving the effective inlet total pressure distribution from the measured distribution.