基于FMECA和FTA的机载制冷系统故障分析

发布时间：2018-07-20 14:42

【摘要】：随着时间、技术的不断发展,机载制冷系统的作用越来越显著,且机载制冷系统的不断更新换代使得其复杂程度也大大提高。机载制冷系统在运行过程中不可避免的会出现故障,为了提高机载制冷系统的可靠性和安全性,很有必要对机载制冷系统的故障进行分析、诊断。本文针对机载制冷系统,采用了故障影响模式及危害性分析(Failure Mode Effects and Criticality Analysis,简称FMECA)和故障树(Fault Tree Analysis,简称FTA)分析方法,并结合Matlab/Simulink仿真平台,对机载制冷系统进行了故障分析,主要工作内容和结论如下:(1)对机载制冷系统原理进行分析,确定系统关键部件及其之间的故障逻辑关系。按照国家军用标准,收集了相关数据;针对换热器、水分离器、活门、传感器、涡轮等制冷系统主要部件进行FMECA分析,制成FMECA表格。(2)在FMECA的基础上,运用FTA方法,建立了各部件和以座舱温度异常、座舱压力异常为顶事件的故障树模型,并对其进行故障树分析,得到了故障排序。分析结果表明,涡轮部件故障是导致座舱温度高于舒适区温度的主要原因,座舱温度低于舒适区温度归因于调节活门故障,而压力传感器故障导致了座舱压力异常。(3)搭建了机载制冷系统的仿真模型,并进行了故障仿真。根据座舱通风温度结合严酷度等级,利用部件效率对系统故障进行定义,为故障仿真提供了故障判据。对不同工况下的机载制冷系统进行仿真计算,得到单一故障时系统各部件出口参数的数据,进而建立了机载制冷系统的故障数据库。通过对各部件出口参数的监测与对比,可以快速找到故障原因和故障模式的排序,这说明以座舱通风温度作为故障判据,利用部件效率来量化不同严酷度下的故障具有可行性。
[Abstract]:With the development of technology and time, the function of airborne refrigeration system is becoming more and more important, and the complexity of airborne refrigeration system is greatly improved. In order to improve the reliability and safety of airborne refrigeration system, it is necessary to analyze and diagnose the fault of airborne refrigeration system. In this paper, the fault analysis method of airborne refrigeration system based on failure Mode effects and criticality Analysis (FMECA) and Fault Tree Analysis (FTA) is adopted, and the fault analysis of airborne refrigeration system is carried out based on Matlab / Simulink simulation platform. The main contents and conclusions are as follows: (1) the principle of airborne refrigeration system is analyzed to determine the key components of the system and its fault logic relationship. According to the national military standard, the relevant data are collected, and FMECA tables are made for the main parts of refrigeration system, such as heat exchanger, water separator, valve, sensor, turbine and so on. (2) based on FMECA, FTA method is used. The fault tree model of each component and the cabin temperature anomaly and cabin pressure anomaly as the top event is established, and the fault tree analysis is carried out, and the fault ranking is obtained. The analysis results show that turbine component failure is the main cause of cabin temperature higher than comfort zone temperature, and cabin temperature lower than comfort zone temperature is attributed to adjustment valve failure. The fault of pressure sensor leads to abnormal cabin pressure. (3) the simulation model of airborne refrigeration system is built and the fault simulation is carried out. According to cabin ventilation temperature and severity grade, the system fault is defined by component efficiency, which provides fault criterion for fault simulation. The data of the exit parameters of each component of the airborne refrigeration system under different working conditions are obtained by simulation and calculation, and the fault database of the airborne refrigeration system is established. By monitoring and comparing the exit parameters of each component, the fault causes and fault modes can be quickly found, which shows that it is feasible to use the cabin ventilation temperature as the fault criterion and use the component efficiency to quantify the faults with different severity.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V267

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