航空发动机尾气静电带电机理分析与试验研究

Mechanism and Experimental Study on Aero-Engine Exhaust Electrostatic Charging

航空发动机工作时燃烧室内发生复杂的物理化学变化，生成大量带电粒子，导致发动机尾气静电带电；理论分析了发动机喷流尾气中带电粒子产生演化过程和带电影响因素，讨论对比了多种测试原理与传感器方案，确立了非接触式静电感应测试方案，研制了共轴喇叭状静电传感器和静电监测系统，开发了自动测试软件并对某型航空发动机进行了机载尾气静电带电试验研究，验证了测试平台的有效性，成功获得了大量喷流尾气静电信号；研究结果表明：航空发动机正常工作时喷流尾气中带电粒子总体显正极性，平均体电荷密度约为0．077nC／m^3，发动机等效充电电流为2．26nA。

Complex physical and chemical reactions in combustion chamber while aero-engine＇ s working will generate a large number of charged particles, causing the aero--engine electrification. The formation and evolution of charged particles is investigated using a theoretical model. Particular emphasis is placed on the comparative analysis （contrast analysis） of electrostatic testing principle and sensor scheme. A special electrostatic sensor, an electrostatic monitoring system, and an automatic monitoring software platform are developed. The efficiency of the platform is shown by the field test on a certain type of aircraft, which provides a large amount of exhaust gas electrostatic signal. Study results indicate that the starting and stopping process of aero-engine will produce significant electrostatic signal, the polarity of aero-engine normal exhaust gas＇ s charged particles is positive, the average volume charge density is 0. 077nC/m^3 , the equivalent charging current is 2. 26hA, the corona discharge frequency caused by aero-engine exhaust electrification is 14kHz.