Mathematical modeling of an axial compressor in a gas turbine cycle

Marcin Plis, Henryk Rusinowski


Contemporary thermal diagnostic systems of power units require advanced computational tools, including mathematical models.
These models should have a simple structure and short computing time. These conditions are satisfied by models that
include mass and energy balances as well as additional empirical functions whose coefficients are estimated by using the
measurement results. This paper presents a simulation model of an axial compressor which forms part of a gas turbine
unit with a rated output of 125.4 MW. The model was developed with the use of a generalized compressor map, describing
the relationship between corrected air mass flow rate, pressure ratio, isentropic efficiency and corrected rotational speed.
The model encompasses the empirical formula for compressor internal efficiency, which additionally considers the effect of
variation of the angle of inlet guide vanes. The unknown values of empirical coefficients which appear in this equation were
estimated on the basis of operating data. The calculation results obtained were compared with the measurement results. The
quality of the model prediction was evaluated and conclusions were drawn.


Mathematical modelling, Gas turbine, Axial compressor, Empirical functions, Inlet guide vanes of compressor

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