EVALUATION OF TURBINE CHARACTERISTICS FOR LOW-SPEED AND LOAD

A method for the evaluation of complete characteristics down to speed lines near zero and to extreme load numbers is presented, starting fro m measured speed lines in the upper speed range and measured isolated points at low speed or blocked rotor. For this purpose turbine charact eristics are used with reduced flow and load numbers especially suitab le for extrapolation and also proved for performance synthesis calcula tions of gas turbines. Different from parameters conventionally used f or characteristics all parameters are steady even for pressure increas e. The Mach number influence disappearing at low speed allows the extr apolation towards lower speeds. For the use in existing programs the c haracteristics can be reconverted to the conventional form. There are not covered reverse speeds and flows as well as Reynolds number effect s.