Simulation of a Governed Marine Gas Turbine in Faulty Conditions

Abstract: The gas turbine plants, thanks to their superior power density in comparison with other thermal engines (i.e. diesel engines), represent an appreciated and competitive typology of prime movers, of particular interest for the propulsion systems of high speed marine vehicles, typically based on both propeller and waterjet propulsion. Because of the high performance required by these high speed ships propulsion plants, in order to ensure the vessel safety in every foreseeable condition, it may be very useful the availability of validated and reliable gas turbines simulation mod-els, to be used not only for the performance prediction in normal operative situations, but also when the gas turbine is run-ning under faulty conditions. In the paper a gas turbine thermodynamic mathematical model, specifically developed by the authors for ship propulsion plants studies, is used for the simulation of the LM 2500 gas turbine performance variations caused by six typical faults. For a more realistic prediction of the faults consequences on the gas turbine performance, also the gas turbine governor used in typical ship propulsion plants is modelled, while the load resistance (propeller or waterjet pump) is simulated, in this application, by means of simple relations. The faulty gas turbine simulation results, relative to the main engine parameters variations, obtained for different load conditions, are presented and analysed. A gas turbine faults matrix is then generated and reported in the paper.