Research On Simulation Of Marine Gas Turbine Based On Bond Graph

Marine gas turbine works in the marine environment,its working conditions are harsh.In the course of marine gas turbine operation in the event of failure,it will cause great economic losses and may result in casualties.Because gas turbine is more expensive,it is not allowed to carry out fault experiments on actual gas turbine injection failures.For safety and economy reasons,the simulation model of gas turbine is established by computer simulation,and the dynamic characteristics of gas turbine are analyzed.Thus,it is especially important to carry out some research on fault simulation.A three-shaft gas turbine is taken as the research object in this paper,and a bond graph model of the marine gas turbine is established by using bond graph theory,which provides a new method for dynamic modeling of gas turbines in engineering and also expands a new application fields for bond graph theory.Then,the research on the gas turbine fault simulation is carried out based on the marine gas turbine bond graph model.Finally,a marine gas turbine simulation verification platform is developed.And the main contents include the following aspects:(1)Some basic concepts commonly used in bond graph theory,the basic components of bond graph and the causality of bond graph are studied.After that,some problems existing in the basic elements of bond graph are analyzed,and the concept of multi-bond graphs and pseudo-bond graphs is derived,which provides a theoretical basis for the next gas bond graph modeling.(2)A bond graph model of marine gas turbine,a bond graph model of fuel system and a control system model are established on the bond graph modeling software 20-sim based on bond graph theory.Then,according to the coupling relationship of gas turbine engine,fuel system and control system,the closed-loop connection of these models is realized,and the bond graph model of marine gas turbine is established.Finally,the model simulation results are compared with the experimental data of gas turbine,and the results show that the error is within 7% range.Thus,some simulation studies are carried out by using the model in this paper.(3)Firstly,research on the degradation of salt fog fouling in the compressor is carried out.It is considered that the degradation of salt fog fouling of the marine gas turbine mainly occurs on the low-pressure compressor.A degenerative simulation of salt fog fouling of the compressor is proposed,which can be used to establish salt fog degradation factor model.Then,the effects of load,ambient temperature,inlet pressure loss and salt fog deposition rate on the degradation of gas turbine performance are simulating analyzed.The degradation law of marine gas turbine performance parameters under different operating conditions and different scale depositions was obtained.Finally,a method to estimate the operating cost of marine gas turbines is proposed,which can estimate the transient changes and cumulative changes of operating costs caused by salt spray fouling in a certain cleaning cycle.In addition,four kinds of typical faults,that is,a single gas line fault of a gas turbine body,a gas line combination fault of a gas turbine body,a single fuel system fault,and a coupled fault of a gas turbine body and a fuel system,are also simulated to obtain various fault characteristics.(4)Through the transformation of the ship gas turbine bond graph model,a marine gas turbine simulation verification platform is designed under the LabVIEW development environment.The hardware,human-computer interaction interface and the program panel of the platform are designed.After that,the simulation and simulation data transmission function of the platform in normal state,degenerate state,typical fault state are verified,which proves that there is no conversion error in the process of converting the ship gas turbine bond graph model into marine gas turbine simulation and verification platform,and meets the required functional requirements.Thus,the platform provides a verification environment for engineering applications such as gas turbine health assessment,fault diagnosis and trend forecasting.