A step further in gas turbine dynamic simulation

Abstract

Non-proprietary gas turbine transient performance models that deal with volume dynamics in the open literature usually do not consider heat transfer effects and friction existing in the volume walls. Such models are more than satisfactory for the analysis of aero gas turbines because the associated volumes of their components are inherently small and therefore treated as adiabatic, frictionless and passing low Mach number flows. When focusing upon gas turbines with heat exchangers, such as those working on regenerative cycles, on the other hand, these simplifying hypotheses may not be valid. The analysis model suggested in this work takes account of non-adiabatic volume dynamics with friction and high Mach number flows. The model is applied to the study of a regenerative-cycle gas turbine, through which the need for a more complete analysis model is demonstrated. The result of the study showed that the regenerator cold section volume has a greater influence on the dynamics than the hot section volume, this causing the power output. Friction has little influence on the dynamic response but causes a decrease in the steady state power output, as expected. Heat exchange also reduces the power output and lowers the transient engine surge margin.