最大Lyapunov指数用于压气机局部性能的分析

对压气机叶尖、叶根失速类型的判断有利于在设计中增加控制措施以扩大压气机稳定工作范围。压气机内部流动为复杂的非线性系统,利用非线性时间序列分析中的最大Lyapunov指数方法,分别对单级和15级低速轴流压气机稳定工作状态下不同叶高处的动态总压试验数据进行分析,发现最大Lyapunov指数较大的区域容易失速,得到了此压气机叶尖与叶根进入失速的先后顺序,与失速过程的动态总压信号利用低通滤波方法进行失速类型判断得到的结论相一致。     

压气机/风扇叶片自动优化设计的研究现状和关键技术

 着重介绍和分析了近年来快速发展的压气机叶片自动优化设计方法现状、应用特点以及关键技术。通过分析指出：自动优化设计方法设计效率高,适用于高气动性能指标压气机/风扇设计;为缩短优化时间和提高搜索效率,优化算法应首选并行遗传算法;今后在叶片参数化方法、加速流场计算方法以及提高遗传算法的搜索效率方面需进行进一步研究。     

Multi-scale nature of non-blade-order propagating flow disturbances in axial compressors

Non-blade-order flow disturbances, also referred to as pre-stall disturbances or tip flow unsteadiness, are closely related with compressor instabilities. The present work provides a comprehensive investigation on multi-scale nature of non-blade-order disturbances and the underlying flow physics in axial compressors. By applying full-annulus Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations, along with space–time correlation and spatial Fourier decomposition, to the disturbed pressure, the propagating feature of the non-blade-order disturbances is obtained. Further, a bridge between non-blade-order disturbances and the evolution of unsteady vortex has been set up. The results show that non-blade-order disturbances, featured as short-length-scale (35 modes across annulus), first appear as the occurrence of tip leakage vortex fluctuation, while the compressor still operates far from stall. Leading-edge radial vortex appears at near stall condition, and its movement induces a circumferential propagating disturbance overlaying on the one induced by oscillating tip leakage vortex. The interaction of the short-scale disturbances with a low-amplitude long-scale (of circumference) disturbance is observed, which results in disturbances with multiple scales of consecutive spatial modes, along with multiple frequency peaks in spectra. The compressor falls into stall as the circumferential nonuniform scattering of the leading-edge vortexes occurs. The densely- and sparsely-scattered leading-edge radial vortexes induce a high-amplitude long-scale (of circumference) disturbance, i.e. stall disturbance.     

多级压气机中可控扩散叶型研究的进展与展望 第一部 分可控扩散叶型的设计与发展

可控扩散叶型（CDA）的优化设计是目前国外对亚音、跨音速压气机叶型研究的主要内容之一。本文对CDA研究的必要性、CDA产生的背景、第一代CDA和考虑端部流动的第二代CDA的特点及设计方法进行了综述。CDA起源于超临界机翼翼型，通过控制吸力面的扩压过程，消除或减弱激波、降低损失、增加可用冲角范围。围绕这一设计准则和目标，提出了很多设计方法，归纳起来主要有反问题设计方法和正问题设计方法。国内对CDA的研究起步较晚，且大都集中在理论和设计方法的研究上。