چكيده به لاتين
Abstract:
The gas turbine possesses remarkable capabilities in generating electric power and mechanical driving force in industrial applications and propulsive force in aerospace applications. Bond graph-based modeling approach which is structured according to the energy transfer between system components can be evaluated as a means for gas turbine modeling.
In this thesis, the performance modeling of an industrial gas turbine and associated systems is carried out using bond graph approach. In the first step, the bond graph technique is implemented to provide the models for gas turbine components. In the second step, the bond graph model is developed by considering two gas turbine subsystems including the electric starter and clutch systems in order to evaluate the ability of bond graph approach for modeling new systems related to the gas turbine. In the section of validating the transient results, the bond graph simulation outputs of industrial gas turbine are compared with the model of GSP software for a specific loading profile. In this evaluation, the performance of bond graph and GSP models with regard to the estimation of CAMF, NGG and EGT is compared. The maximum amount of error, i.e. 2.17 %, occurred for the EGT case. This implies the appropriate accuracy of simulation for the transient case. The results of the steady-state modeling of industrial gas turbine are validated with those of the experiments on gas turbine. To assess the simulation results, the turbine loading profile in different temperature conditions as determined by the turbine manufacturer are utilized in the model. The bond graph model with an average error of 0.74 % had an acceptable accuracy in predicting the mass flow out of the gas turbine. The average error of estimating the turbine thermal efficiency in the loading range of 50 – 100 % is about 2.25 %. Moreover, in the third step, modeling of an aero gas turbine including the turbojet engine and its start system as well as its application in JetQuad is developed and validated. Regarding the aero engine, the simulation results of the turbojet bond graph model and its electric starter system are compared with engine experimental test results. For this purpose, an experimental platform of a small turbojet engine is provided. A monitoring system is then developed for the purpose of extracting data from the engine so as to record experimental data. Finally, the engine steady-state and transient simulation results are evaluated against the experimental findings, indicating adequate accuracy of model behavior in approximating the parameters of RPM and EGT.
Keywords:
Industrial gas turbine, bond graph approach, modular modeling, aerial engine (turbojet engine), electric starter system, Jet Quad system, clutch system.
