涡喷发动机尾气静电监测及气路故障特征

利用涡喷发动机试车台和新研制的小型涡喷发动机完成了一系列静电监测实验,获取了涡喷发动机尾气静电信号特性,并通过分析静电信号特征证实了尾气静电监测技术对发动机气路部件机械故障的监测.研究发现发动机尾气静电信号的细微变化与发动机工况相关,通过分析第102试车阶段的静电信号发现活动率水平出现了与发动机工况同步变化的情况,验证了活动率水平是一种可作为表征尾气中微小颗粒的带电情况的特征参数；在102～108试车阶段中,发动机出现了燃烧室内壁积炭、燃烧室内壁轻微烧蚀和气路润滑油泄漏故障,根据静电信号的统计分析以及大时间尺度的趋势分析,发现活动率水平、正(负)事件率可作为预警参数来反映因这些故障而导致尾气静电整体水平的变化.

Exhaust gas electrostatic monitoring and gas path fault feature for turbojet engine

Some experimental stages of electrostatic monitoring explorative experiments which used the engine test bed and a certain small turbojet engine were conducted. The characteristics of electrostatic signal of the turbojet engine's exhaust gas were obtained, and the electrostatic monitoring technology's ability of monitoring the engine gas path mechanical faults was verified.Then,the result of the next research shows that electrostatic signal of the turbojet engine's exhaust gas may change a little with the engine conditions.There are some evidences obtained by the analysis of the electrostatic signal in stage 102 showing that the activity level changes with the engine conditions,and the activity level is a characteristic parameter of the charged micronized particles in the turbojet engine's exhaust gas.In the process of engine test from stage 102 to stage 108,there were some faults such as engine combustion chamber carbon deposition fault,mild ablation breakdown and lub oil leaking in gas path.There were some changes in electrostatic whole level of engine's exhaust gas which can be found by analyzing signal statistical and long time domain to make characteristic parameters of the electrostatic signal like active level and positive (negative) event rate as early-warning parameters corresponding with these faults.