A method of predicting the performance of axial flow turbines using a digital computer to develop performance maps

Abstract

A theoretical method of predicting the performance of subsonic, axial flow, multistage turbines is presented together with the digital computer program for computing all the dimensionless performance parameters required to completely define turbine performance. A small two stage turbine, for use in space vehicles, was used to demonstrate the application of the method. A complete set of performance maps were drawn and analyzed. The dimensionless performance parameters for any given flow condition could be obtained from the maps. The computer program proved to be extremely flexible and useful. The effect of blade row redesign could be easily determined. Comparison of the extremely limited amount of open cycle test data with program results showed that the method would provide a design engineer the means of predicting the performance of a given turbine design. The accuracy of such a prediction was shown to depend greatly upon the estimation of rotor tip clearances and the measurement of flow areas corresponding to the clearance. The computer program provides a means for trial and error determination of the rotor tip clearances when operating at high temperatures if accurate test data is available. Although the computer program was written in Fortran language for the Control Data Corporation 1604 Computer at the U.S. Naval Postgraduate School, it should be compatible with most computer installations through out the country.