Research On Method And System Of Electrostatic Monitoring For Gas Path Faults Of Aero Engine

The gas path components with high failure rate are owing to work in high temperature, high-pressure environment for long time. The failures of gas path components are the main reason for serious accident. The health management system of aero-engine is with a strong demand for the new condition monitoring techniques such as gas path electrostatic monitoring technology being certain hotspot. There is a core research subject throughout the paper which is the research of gas path electrostatic monitoring of their failure in aero-engine. Some themes are carried out to undertake the core research subject, such as electrostatic sensor design theory, electrostatic signal preprocessing methods and parameters, the simulation experiments include rub and hot end component faults, the online monitoring method for abnormal state gas path, fault monitoring methods and application and so on.The main work and results of the thesis are as follows:(1)According to the principle of multi-charge electrostatic induction of charged particles in gas path, it is being the theoretical framework to guide the design and manufacture of an electrostatic sensor including a functional model of the electrostatic sensor, measuring circuit and physical measurement mode. Three species of electrostatic sensors are designed and successfully applied to aero-engine during the hundreds of hours experiment in test bed. The formation of electrostatic monitoring system for gas path faults implements in continuous on-line monitoring test engine gas path component status and alerts gas path faults, which can set the necessary supporting information to the commissioning officers who can take the termination of the test and troubleshooting.(2)The preprocessing methods for electrostatic signal makes the foundation to calculate the characteristic parameters for electrostatic monitoring system for gas path faults. The research of calculation method for electrostatic charge signal solves the problem being continuous online calculation of electrostatic charge signal. The comprehensive study of the electrostatic signal feature extraction method using the measured aviation turbojet engine monitoring signal obtains the formation for characteristic parameters to reactive the level of gas path electrostatic change.(3)The studies of electrostatic monitoring is based on some fault simulation for gas path faults in aero-engine. The aero-engine rubbing fault simulation is designed and manufactured by ourselves for electrostatic monitoring experiment station, which carried electrostatic monitoring experiment of multi-blade- casing rubbing fault simulation, the whole rubbing fault, local rubbing faults. Using the self-developed hot end component failure simulation equipment carried out the engine smoke electrostatic monitoring experiments, combustion fault simulation experiments, the hot end components ablated block fault simulation experimental, and analyzed the hot end component failure can influence changes in signal characteristics by the electrostatic parameters.(4)The first time electrostatic monitoring experiments of aviation turbojet engine gets a lot of the raw data of electrostatic monitoring signal which can extract the root mean square value from the electrostatic voltage signal as a single parameter to establish a healthy baseline model. Because of the problem that the electrostatic level change with the aero engine operating conditions, it creates aero engine electrostatic health baseline model group with multiple conditions. In order to solve the problem that engine existing individual differences in the level of the gas path electrostatic for the causes such as manufacture or use, it carry out the study of the adaptive electrostatic baseline health, proposing adaptive electrostatic methods, health baseline update adaptive update policy being followed, which help achieve the electrostatic monitoring of gas path with abnormal conditions under great timescales.(5)The study of multi-parameter adaptive healthy baseline model is applied in electrostatic monitoring of gas path faults during the durability test procedure of aero engine. The detail change variation of the electrostatic signal characteristic parameters corresponding with the oil leaking in gas path, combustion chamber carbon deposits, abnormal sound of aero engine are researched according to the fault signal obtained in testing process. The study of the early warning strategy during the fault monitoring process reduces the amount of computation and hardware resource requirements for electrostatic monitoring system for gas path faults. The effects of maintenance activities on the level of gas path electrostatic is researched and explored the possible to evaluate the effect of maintenance activities based on the analysis of the gas path electrostatic and the charge of the electrostatic signal characteristic parameters when there were some maintenance activities such as replacing the seal, removing combustion chamber carbon deposits.