Correlations to include heat transfer in gas turbine performance calculations

A modern technique is presented to include heat transfer in modular gas turbine performance calculation programs. The basically new idea is to use heat transfer correlations which present the non-dimensional heat flow in engine components dependent on the most relevant parameters of the working fluid. These are the Biot numbers in steady-state operation whereas in transient operation the Fourier number describes the additional time dependency of the heat transfer process. This integral approach to model heat transfer without describing the local phenomena in detail perfectly matches the techniques which are usually applied in performance calculation procedures. The general representation of non-dimensional heat flow is derived with a strictly theoretical approach on the basis of the governing physical relations. As an example for a more realistic engine component, the representation for turbines is derived and the resulting correlations are discussed in detail.The non-adiabatic performance calculation procedure using heat transfer correlations is applied to a twin-spool bypass engine. The results show the typical behavior in the phase of thermal stabilization after an acceleration which is known from the open literature.