Accession Number : AD0851905

Title :   Propulsion System Flow Stability Program (Dynamic). Part X. Explicit Stall Prediction Model - Theory and Comparison of Computed and Experimental Results.

Descriptive Note : Final technical rept. 20 Jun 67-30 Sep 68 on Phase 1,

Corporate Author : NORTH AMERICAN ROCKWELL CORP LOS ANGELES CA LOS ANGELES DIV

Personal Author(s) : Jansen, W. ; Smith, G. E.

Report Date : DEC 1968

Pagination or Media Count : 137

Abstract : In a jet engine, surge is in general initiated by disturbances generated by such mechanisms as unsteady inlet flow conditions, combustion instabilities, and rotating stall in the compressor. In this study the phenomenon of rotating stall was analyzed with the emphasis on the development of a prediction method, and the results show that in the absence of combustion instabilities and unsteady inlet flow conditions, a successful link between the occurrences of rotating stall and surge can be established. The problem of predicting the occurrence of rotating stall in a multistage compressor is subsequently treated theoretically. The theoretically derived equations are then used to predict the surge conditions in a number of single and multistage compressors for which test data are available. The agreement between the predicted and measured operating conditions at which rotating stall occurs is very good for single rotor cases. For the multistage compressors it was not only found that the correlation between the calculated occurrence of rotating stall and the measured surge condition is good, but also that the locations at which rotating stall is first calculated to occur correspond closely to those found by experiments. The analysis has been expanded to include the effects of inlet flow distortions. However, no comparisons with experimental results have been made to validate the results. Suggestions for future studies have been indicated. (Author)

Descriptors :   (*TURBOFAN ENGINES, AXIAL FLOW COMPRESSORS), (*AXIAL FLOW COMPRESSORS, AERODYNAMIC CHARACTERISTICS), (*TURBOJET INLETS, FLOW SEPARATION), MATHEMATICAL MODELS, STALLING, PREDICTIONS, PERFORMANCE(ENGINEERING), ENGINE SURGE, GAS FLOW, STABILITY, AIRCRAFT ENGINES, GAS TURBINES, THEORY.

Subject Categories : Fluid Mechanics
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE