Abstract:
Two new methods for the simulation of gas turbine fuel systems, one based on
an inter-component volume (ICV) method, and the other based on the iterative
Newton Raphson (NR) method, have been developed in this study. They are able
to simulate the performance behaviour of each of the hydraulic components such
as pumps, valves, metering unit of a fuel system, using physics-based models,
which potentially offer more accurate results compared with those using transfer
functions. A transient performance simulation system has been set up for gas
turbine engines based on an inter-component volume (ICV). A proportional-
integral (PI) control strategy is used for the simulation of engine control systems.
An integrated engine and its control and hydraulic fuel systems has been set up
to investigate their coupling effect during engine transient processes. The
developed simulation methods and the systems have been applied to a model
turbojet and a model turboshaft gas turbine engine to demonstrate the
effectiveness of both two methods. The comparison between the results of
engines with and without the ICV method simulated fuel system models shows
that the delay of the engine transient response due to the inclusion of the fuel
system components and introduced inter-component volumes is noticeable,
although relatively small. The comparison of two developed methods applied to
engine fuel system simulation demonstrate that both methods introduce delay
effect to the engine transient response but the NR method is ahead than the ICV
method due to the omission of inter-component volumes on engine fuel system
simulation. The developed simulation methods are generic and can be applied to
the performance simulation of any other gas turbines and their control and fuel
systems.
A sensitivity analysis of fuel system key parameters that may affect the engine
transient behaviours has also been achieved and represented in this thesis.
Three sets of fuel system key parameters have been introduced to investigate
their sensitivities, which are, the volumes introduced for ICV method applied to
fuel system simulation; the time constants introduced into those first order lags tosimulate the valve movements delay and fuel spray delay effect; and the fuel
system key performance and structural parameters.
