航空发动机进气道出口截面喘振波的分布

Distribution of surge waves at inlet exit section for a aeroengine

关键词:  进气畸变  小波分析  喘振波  压力分布

Key words:  Air inlet flow distortion  Wavelet analysis  Surge waves  Pressure distribution

摘要:

用扰流插板使涡扇发动机进气道内产生不对称分布的总压畸变并使发动机出现喘振。在进气道出口即发动机进口截面测取两种不同转速下发动机的喘振压力波。应用小波分析奇异点理论,采用模极大值原理和高阶Daubechies小波多尺度分析,对喘振压力信号进行处理,得到发动机喘振波在其进口截面的波形分布特征。揭示了在两种转速下,喘振波在截面上的分布相似,其频率和幅值与转速成正比。截面中心部分表现为正脉冲,周围部分为负脉冲。在垂直方向上的幅值较大,而两翼较小。对该分布特征进行了分析,初步的推论为:高压压气机引起喘振,稳态压力畸变最严重的区域和未受到畸变扰动的区域,喘振波最为强烈。

Abstract:

The asymmetric distribution of total pressure distortion is produced by using disturbing inserted-board in the air inlet.When the aeroengine surges were appearing,at the inlet exit section,the surge pressure waves at two different rotating speeds were measured.The surge pressure signals were processed with wavelet analysis singularity theory with the module maximum value principle and Daubechies high-class multi-scale wavelet analysis.Their distributing characteristics were found.It shows that in case of two different rotor speeds,the surge waves distributions are similar at the same section.Their frequencies and values have direct ratios with the rotor speeds.The pressure pulses are positive in the section centre and negative at the circumference.The values of the surge waves in the area around the center vertical bisector are larger than those in the area around the diagonal diameters to its left and right.These distributing characteristics were analyzed and it shows that the surge waves are caused by the high pressure compressor.The surge waves are the strongest in the area where the steady total pressure distortion are the strongest and in the area where no distortion occurs.