The Aircraft Pneumatic System Modeling And Studying On Fault Mechanism

The Air Pneumatic System is widely distributed. The aim of The Air Pneumatic System of aircraft is to supply high temperature and high pressure air to down stream system, to meet the flight crew, passengers and equipments with the normal living condition,besides normal needs. Due to the special status of The Air Pneumatic System in aircraft, the research of The Air Pneumatic System has increasingly been noticed by people home and abroad. However, these studies are more about temperature regulation system modeling and low pressure fault analysis of The Air Pneumatic System, which are rare about the components of The Air Pneumatic System and the entire system modeling and failure simulating. So it is rather essential to have the research on modeling and fault simulation of The Air Pneumatic System.The modeling and fault simulation for the Air Pneumatic System has been built based on the mathematical models of the components in Air Pneumatic System to realize simulation and mechanism analysis for fault system. Based on the modeling and fault simulation research of air cycle machine, according to the law of conservation of energy and equation of momentum and force balance, the mathematical models of the heat exchanger, compressor,turbine and air cycle machine integral mathematical model are established. Using SIMULINK,the failure symptoms and dynamic curves of the main parameters in the conditions of part failure, such as the Flow Control Valve(FCV), heat exchanger and ram air door, are given and discussed in detail. The agreement of the simulation result and the result in the airline fault collection manual indicates that the ACM model is a valuable reference to the technicians for diagnosis. And then summarize the experience and methods of the air cycle machine modeling and fault simulation research to built the mathematical models of the high pressure valve, the overpressure valve, the pressure regulating valve, the fan air valve, the precooler, as well as the whole Air Pneumatic System, Using SIMULINK, the failure symptoms and dynamic curves of the main parameters in the conditions of part failure, such as the pressure regulating valve, fan air valve and transducer, are given and discussed in detail. The result indicates that these methods are correct and has great application value in future.