计了一种特定尺寸的静电传感器,并将其装配在涡扇发动机低压涡轮出口附近的尾喷管管壁,以民用涡扇发动机为静电传感器载体及监测对象开展静电监测实验.以一个完整性能试车过程为周期,采集周期内的尾气静电信号.进一步对静电信号和发动机性能参数进行数据对比分析,同时对测试过程中异常状态下活动率水平(AL)和负事件率(NER)进行计算.实验验证了航空发动机静电监测技术具备机载化的可行性,实验结果表明:正常状态下静电信号电压幅值大小约为5mV,静电水平跟随运行功率变化并呈正相关性;静电传感器对尾气中存在的异常颗粒具有良好的监测效果,在发动机富油状态下静电信号的活动率水平和负事件率分别达到14pC及8%.
A kind of electrostatic sensor with specific size was designed and assembled on exhaust nozzle in wall of turbofan engine nearby the low pressure turbine, and the civil turbofan engine was served as electrostatic sensor carrier and monitoring object in exhaust electrostatic monitoring experiment. The whole performance test process was taken as test period, and exhaust electrostatic signal was fully acquired during the test period. Data processing and contrastive analysis of electrostatic signal data and aero engine performance pa rameters were taken, meanwhile the activity level (AL) and negative event rate (NER) of abnormal signal in the test period were calculated, and reason of the abnormity was analyzed. This experiment verified the feasibility of airborne installing for electrostatic monitoring technology. Results show that, the electrostatic signal is about 5mV in normal condition, electrostatic level changes with the operating power and has an obvious positive correla tion trend; electrostatic sensor has great effects on monitoring abnormal particle in exhaust,the AL and NER can reach 14pC and 8% in fuel-rich combustion condition.