Modeling And Fault Simulation Of Propellant Filling Equipment

Propellant filling system, which provides fuel and oxidant for rocket engine, is an important composition of test-bed. In order to ensure and improve its reliability and security, it is urgent to collect fault characters, which are used for accurate and effective fault detection. However, as the real fault data are very limited, it is considered that fault mode analysis based on fault simulation is a feasible research method.In this paper, the research based on object-oriented modeling method, is carried out on the moduar modeling and fault simulation of liquid rocket engine propellant filling system. The main contents of this thesis include:(1) The concept and principle of object-oriented modeling method are described in detail, and the overviews of modeling platform Dymola and language Modelica are covered.(2) Based on the understanding of real physical constitutions of filling system, the work of modular decomposition is done with the idea of modular modeling.(3) For pneumatic and hydraulic sub-system of the filling system, there build modules of real compenents including sources, medium, transport lines and otherwise in the order of first mathematic formulas and then Modelica sentences. These modules compose two model libraries-pneumatic library Gas and hydraulic library Liquid, from where we can take modules to build model of the whole filling system in terms of"parts model-sub-system model-system model". And then parameters are set appropriately and the model is made to simulate, the simulation precision is checked after that by contrasting simulation results and real test data.(4) Based on the normal ones, models under the conditions of leak and block are simulated, during which three methods for fault simulation are summarized: adding/ detracting modules, modifying modules and setting parameters of modules. By using of these methods, data library of fault simulation can be established.The simulation results show that normal and fault simulations of the filling system based on object-oriented modeling are efficient. This method has great significance for consummating fault mode liabrary and improving the security of liquid rocket launching test.