涡喷发动机对湍流型动态压力畸变频率响应的实验研究

 一、研究与分析方法 本实验在地面台架上的一台涡喷发动机上进行。图1为试验装置前段及挡板装置简图。挡板用以产生较强的湍流型动态压力畸变,而压气机出口测点的动态压力P₂*与进口环面相应半径上测点的动态压力P₁*则构成相关分析的输出与输入信号。动态压力测量采用Kulite微型固态压阻式传感器,并经放大系统,由磁带机记录下在湍流型动态压力畸变工况时发动机进入漂移型喘振的压力信号过程,试验后通过磁带机回放压力脉动数据,并在信号分析仪上处理。为了得到准确的喘前压力脉动数据,直接以喘振发生时的P₂*激烈下降作为同步外触发信号，并采用负向时间延迟来控制喘前数据采集，从而保证了喘前信号的可靠性。

EXPERIMENTAL INVESTIGATION ON FREQUENCY RESPONSE OF A TURBOJET ENGINE TO TURBULENCE-TYPE DYNAMIC DISTORTION

The inlet and exit fluctuating pressure signals of a compressor prior to "drift surge"are investigated by correlation and spectral analyses. It is found that the stochastic process of fluctuating pressure is no more stationary near the inception of the "drift surge". The surge of the tested engine under the, dynamic distortion is caused by rotating stall. The whole unsteady operating time for the engine to get into surging is about 5 seconds and the process is characterized by rotating stall cell spreading forwards from the rear stage over the whole annular passage of the compressor. It is worth notice that the tested engine is sensitive to pressure fluctuations with certain frequencies prior to the surge, but strict conclusion needs further experimental investigation.