航空发动机压气机内气液非平衡冷却特性研究

Gas-Liquid Non-Equilibrium Cooling Characteristics of Aero-Engine Compressor

关键词:  航空涡轮发动机  压气机  雾化冷却  相变蒸发  非定常脉动  快速傅里叶变换  功率谱密度

Key words:  Aero-turbine engine  Compressor  Atomization cooling  Phase change evaporation  Unsteady fluctuation  Fast Fourier transform  Power spectral density

摘要:

针对航空涡轮发动机来流雾化冷却对压气机内气动脉动的影响，考虑壁面液膜成形和运动，基于欧拉-拉格朗日多相流方法解析气液两相热质非平衡传输过程，应用快速傅里叶变换方法将压气机性能参数随旋转周期演变规律的时域脉动敏感性转化为频域功率谱密度的直观分析。结果表明，压气机内气液非平衡蒸发相变易诱发流场在时间和空间上非定常的气动脉动，雾化冷却参数与总温比呈线性关系，而与总压比和效率均呈非线性关系。在雾化量0.5%~5%和雾化平均粒径1~9μm内，较低的雾化量或较小的雾化平均粒径时，时域总压比的脉动程度更大；在较低的雾化量或较大雾化平均粒径时，时域总温比的脉动程度更强；而在较高的雾化量或较大的雾化平均粒径时，时域效率脉动程度更高。同时，雾化冷却量变化对湿压缩过程中流场的时域脉动敏感性程度大于雾化粒径变化。

Abstract:

Given the influence of the atomization cooling of the incoming flow of the aero-turbine engine on the internal airflow of the compressor， the non-equilibrium transmission process of gas-liquid two-phase on heat and mass transfer is analyzed based on the Eulerian-Lagrangian multiphase flow method. And then， the motion factor of the liquid film on the wall is considered. Moreover， the time-domain fluctuation sensitivity of the characteristic parameters of the compressor is transformed into an analysis of the frequency-domain power spectral density by the Fast Fourier Transform （FFT） method. Results show that the non-equilibrium evaporation phase transition in the compressor can easily induce the unsteady aerodynamic fluctuation of the flow field in time and space. The atomization cooling parameters have a linear relationship with the total temperature ratio and a nonlinear relationship with both total-pressure ratio and efficiency. In the range of 0.5% ~ 5% water/air ratio and 1~9μm mist particle mean size， the fluctuation degree of total-pressure ratio in the time domain is higher when water/air ratio is lower or mist particle mean size is smaller.The fluctuation degree of total-temperature ratio in the time domain is stronger when the water/air ratio is lower or atomization particle mean size is larger. The fluctuation degree of efficiency in the time domain is higher when water/air ratio is higher or mist particle mean size is larger. Simultaneously， the sensitivity of the change of water/air ratio to the time domain fluctuation of flow field during the wet compressor is greater than that of mist particle size.