Fault Simulation And Software Development Of Liquid Rocket Propulsion System Based On Modelica

Some key technologies involved in the design and health monitoring for pressure- fed propulsion system of liquid rocket have been comprehensively studied. These include the modeling and simulation of propulsion system based on Modelica, the construction of fault mode library, fault injection based on product, redundancy validation of propulsion system and single fault isolation. The results can provide some guidance in the design of propulsion system.Firstly, to solve the problem of muilti-domain and strong nonlinear for propulsion system simulation, some highly replaceable and stable component models are built. The models are validated compared with experimental data. For the design of width and gas type choice for a new liquid rocket propulsion system, some simulation is conducted. The simulation results domenstate:(1) Helium is a n ideal pressure gas with higher pressure efficience.(2) Increasemet in the temperature of the gas can reduce the dosage of the gas, but in another way will level the temperature of the tank. The choice of the temperature should consider the structure of the tank and the volume of the bottle together.(3) Increasement in the width can impel the rise of the tank considerably, but will cause more weight. The effective way is to increase the width in some way.Secondly, due to the isolation of fault injection and product and lack of multi faults injection, retaining the traditional FMEA characteristic and considering the trigger mechanism, a new fault type is presented and a n XML file representing fault mode is constructed. Based on the extendable annotation of Modelica, the construction between the fault mode and fault model is realized. Using the technology of MWorks searching and DOM mechanism, fault injection is realized.Thirdly, to solve some real engineer problem, structure of fault simulation platform is presented. Based on the structure, fault mode library and fault simulation module is designed. By fault simulation, redundancy validation for a new pressure system is done and the results demonstate the reasonability of the scheme. Moreover, for another pressure system, fault isolation based on fault simulation is explored and laid a good foundation for fault diagnose and sensor configuration.